Binary composites of (m-t) BiVO 4 /g-C 3 N 4 as an efficient S-scheme photocatalyst for bromocresol green degradation under visible light

Binary composites of (m-t) BiVO 4 /g-C 3 N 4 as an efficient S-scheme photocatalyst for bromocresol green degradation under visible light | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Binary composites of (m-t) BiVO 4 /g-C 3 N 4 as an efficient S-scheme photocatalyst for bromocresol green degradation under visible light Pooja Mohan, Srinivas Mallapur, C P Prathibha, Rajesh B M, Sakthivel Kandaiah, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7580004/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Jan, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Abstract Design and fabrication of heterojunction comprising the vanadates and g-C 3 N 4 has drawn significant interests from the prospect of full-scale utilization of solar energy. In this context, the present work attempts the simple annealing step for the heterojunction formation between BiVO 4 and g-C 3 N 4 . Strikingly, BiVO 4 adopted pure monoclinic phase, which partially transformed to mixed monoclinic and tetragonal upon combination with g-C 3 N 4 . Such an intricate ternary phase was confirmed by X-ray diffraction technique and optical response measurements revealed the light absorption capacity in the significant portion of solar light. The electrochemical analysis confirmed the extended lifetime for the photogenerated charge carriers. The photocatalytic activity was investigated for the degradation of bromocresol green and composite performance exceeded compared to their pure phase counterparts. The radical scavenging experiments and alignment of band gap edges substantiated the formation of S-scheme heterojunction between BiVO 4 /g-C 3 N 4 . It was proposed that the bulk recombination of charge carriers in BiVO 4 was greatly hindered due to the formation of homojunctions between the different crystal polymorphs of BiVO 4 . On the other hand, interfacial charge carrier transfer process emerging from the interfacial electric field between BiVO 4 and g-C 3 N 4 prompted for the S-scheme charge carrier transfer pathways. Mixed phase S-scheme heterojunction electrochemical measurements Charge carriers Photocatalysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Researchers have focused a lot of attention on semiconductor photocatalysts in recent decades because of their ability to remove organic dyes from contaminated water.[ 1 , 2 ] Among the variety of visible light responsive catalysts, the Bismuth series photocatalysts have garnered a lot of interest because of their distinct physical and chemical characteristics as well as their broad spectrum of light absorption regions.[ 3 , 4 ] Graphitic carbon nitride (g-C 3 N 4 ), bismuth trioxide (Bi 2 O 3 ), tungsten oxide (WO 3 ), cadmium sulfide (CdS), and bismuth vanadate (BiVO 4 ) are well-known visible-light photocatalysts with polymorphs that have attracted a lot of interest due to their crystalline phase-dependent photocatalytic efficacy.[ 5 ] Zircon tetragonal (zt-BiVO 4 ), tetragonal (ts-BiVO 4 ), orthorhombic (o-BiVO 4 ), and monoclinic (m-BiVO 4 ) scheelite are a few polymorphs of BiVO 4 .[ 6 , 7 ] Among these, polymorphs, monoclinic BiVO 4 has the best photo harvesting property due to the relatively narrow band gap (2.4 eV), whereas tetragonal BiVO 4 with 2.9 eV band gap mainly reposes to UV light stimulation.[ 8 , 9 ] The BiVO 4 can be prepared by different routings, such as microwave–assisted synthesis,[ 10 , 11 ] ultrasonic–assisted process,[ 12 ] electrospun,[ 13 , 14 ] multistep ion exchange approach,[ 15 ] hydrothermal method[ 16 , 17 ] and metal–organic decomposition.[ 18 ] These techniques have been used to create BiVO 4 in the shapes of stars, tubes, flowers, sheets, spheres, leaves, and fibers. Narrow band gap and non-toxicity are features of n-type monoclinic BiVO 4 , a typical bismuth oxide. However, a single photocatalyst cannot ensure both strong oxidation and reduction capabilities by having an active visible light response, and vice versa, making it very hard to achieve both of these requirements at once. Furthermore, the low conduction band potential of BiVO 4 hinders the transmission of photogenerated electron-hole pairs and makes it challenging to capture photogenerated electrons, which contributes to the low yield of photogenerated electrons. This suggests that BiVO 4 could be a material of promise for creating composites with significantly enhanced photocatalytic activity. Consequently, efficient methods for accelerating the separation of photogenerated electron-hole pairs need to be developed. A good substitute for heterojunction fabricating is g-C 3 N 4 , which has a multilayer structure, is straightforward to regulate, and exhibits chemical stability. Furthermore, the enormous specific surface area and 2D planar conjugate structure of g-C 3 N 4 allow it to be employed as a huge scaffold for anchoring a variety of platforms. Furthermore, the lamellar structure of g-C 3 N 4 sets it apart from other organic π-conjugated materials. The energy levels of BiVO 4 and g-C 3 N 4 were found to have well-matched overlapping band structures. The combination of g-C 3 N 4 and BiVO 4 can meritoriously prevent the recombination of photogenerated electron-hole pairs and form g-C 3 N 4 /BiVO 4 heterojunctions with excellent ability to photogenerated electron-hole pair transfer and separation. To realize this goal, effective bulk separation of photogenerated charge carriers within semiconductor photocatalysts is a crucial prerequisite.[ 19 ] Moreover, it has been demonstrated that step-scheme (S-scheme) heterojunctions can promote spatial charge separation at the surface level.[ 20 ] In contrast to conventional Z-scheme photosystems, the S-scheme structure's internal electric field, band bending, and coulombic attraction can enhance photocatalytic performance and encourage charge transfer, for instance, the heterojunctions of CsPbBr 3 /TiO 2, [ 21 ] TiO 2 /CdSm,[ 22 ] TiO 2 /In 2 S 3 [ 23 ], BiOBr/C 3 N 4 [ 24 ], CeO 2 /PCN [ 25 ] and Ag 2 WO 4 /WO 3 .[ 26 ] In this work, we report the construction of BiVO 4 /g-C 3 N 4 S-scheme heterojunctions are prepared via a facile solid-state method. The photocatalytic performance of the prepared catalysts was evaluated for the degradation of bromocresol green (BCG). The prominent results were obtained for heterostructures due to the significantly improved light response and interfacial charge transfer efficiency. In addition to increasing the light response range, the coupling of BiVO 4 and g-C 3 N 4 semiconductors provide a driving force for the separation and transfer of photo-generated electron-hole pairs. Enhanced photocatalytic activity correlated with rate constant, photonic efficiency and electrochemical measurements were discussed in detail. The trapping experiment was conducted to investigate the role of free radicals during the degradation process. 2. Experimental procedure 2.1 Materials Bismuth nitrate pentahydrate Bi(NO 3 ) 3 .5H 2 O), ammonium meta vanadate (NH 4 VO 3 ), ammonium hydroxide (NH 4 OH), hydrogen peroxide (H 2 O 2 ), sodium sulphate (Na 2 SO 4 ), isopropyl alcohol (IPA), para benzoquinone (p-BQ), ethylene diamine tetraacetic acid (EDTA), nitric acid (HNO 3 ), Melamine (C 3 H 6 N 6 ), Bromocresol green (C 21 H 14 Br 4 O 5 S), ethanol and de-ionised water were used during the experiment. 2.2 Preparation of BiVO 4 BiVO 4 was prepared by dissolving 3.959 g Bi(NO 3 ) 3 .5H 2 O and 0.9451 g NH 4 VO 3 in 200 mL of HNO 3 . The resultant mixture was continuously stirred for 2 h to get a homogeneous yellow colour solution. 4M NH 4 OH was slowly added to the mixture to adjust the pH 9, resulting in a yellow-orange colour precipitate and further continued stirring for 1h to form the product. The final product was then dried for 24 hours at 70°C after being centrifuged and washed three times with distilled water and ethanol to get rid of any leftover substances. Further, the product was calcined at 500°C for 5 h in a muffle furnace.[ 27 ] 2.3 Preparation of g-C 3 N 4 The direct heating of Melamine at 550°C for 2 h in a semi-closed alumina crucible, resulting in the g-C 3 N 4 . A low ramping rate of 10°C was maintained. After cooling down naturally to ambient temperature, the yellow g-C 3 N 4 was obtained in powder form.[ 28 ] 2.4 Preparation of Heterojunction BiVO 4 /g-C 3 N 4 composites BiVO 4 /g-C 3 N 4 composites were prepared by mixing a certain amount of BiVO 4 and g-C 3 N 4 and grinding thoroughly in an agate mortar for 5 minutes, further calcined at 500°C for 2 h. 0.1 g of BiVO 4 mixed with 0.9 g of g-C 3 N 4 results in the 0.1BiVO 4 /0.9 g-C 3 N 4 and named as BVG-1 similarly for the 0.3BiVO 4 /0.7 g-C 3 N 4 and 0.6BiVO 4 /0.4 g-C 3 N 4 are designated as BVG-3 and BVG-6 respectively. The characterization details, photoelectrochemical performance and photocatalytic experiment details were amended in the supplementary material S1, S2 and S3. 3. Results and discussion 3.1. Structural and morphological analysis The PXRD patterns of BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 were shown in Fig. 1 . BiVO 4 PXRD peaks at 2θ values 18.9° (110), 28.9° (121), 30.7° (040), 34.6° (200), 35.1° (002), 40.10° (211), 42.4° (015), 45.8° (240), 47.2° (042), 50.21° (220) and 53.3° (161) these planes confirm the monoclinic scheelite structure (JCPDS NO 98-901-2063). The two diffraction peaks at 13.4° (100) and 27.9° (002) confirm the tetragonal phase of g-C 3 N 4 (JCPDS 87-1526).[ 29 , 30 ] Interestingly, the new peaks at 2θ values 23.4° (200) and 31.9° (112), which is attributed to the zircon tetragonal phase of BiVO 4 (JCPDS-00-014-0133), after integrating with g-C 3 N 4 in three heterostructures. These characteristic diffraction peaks confirm that three crystal phases of m-BiVO 4 , (t) BiVO 4 and tetragonal g-C 3 N 4 exist in the BVG-1, BVG-3 and BVG-6 composites.[ 31 , 32 ] The average crystallite size was calculated by using Scherer’s formula and the calculated values were ~ 46.03, 8.92, 40.14, 32.47 and 46.67 nm for BiVO 4 , g-C 3 N 4 and BVG-1, BVG-3 and BVG-6, respectively. Figure 2 shows the FTIR spectra of BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6. The band at 606 cm − 1 represents the Bi–O bending vibration, while at 760 cm − 1 corresponds to V-O includes both symmetric and asymmetric stretching vibrations. The bands at 804 cm − 1 and 871 cm − 1 are due to bending modes of the S-triazine unit [ 33 , 34 ], peak at 1644 cm − 1 representing the sp 2 C = N stretching and bands at 1232 cm − 1 , 1327 cm − 1 and 1455 cm − 1 representing the aromatic sp 3 C–N stretching modes. The typical bands of BiVO 4 and g-C 3 N 4 show a slight shift in the composites due to the interaction between BiVO 4 and g-C 3 N 4 [ 35 ]. Morphology of pristine BiVO 4 , g-C 3 N 4 and three composites of BiVO 4 /g-C 3 N 4 depicted in the SEM images (Figure. 3a-e). Figure. 3a shows that the BiVO 4 had an aggregated morphology [ 36 ], and Figure. 3b depicts the irregular nanosheet morphology of g-C 3 N 4 . Figures (3c-e) displays, that upon increasing the content of BiVO 4 , more aggregation occurs on the layered g-C 3 N 4 structure in the composites. Figure 3 f shows the EDAX technique confirms the presence of Bi, V, C, N and O atoms of in the BiVO 4 /g-C 3 N 4 composite. To gain a clear understanding of the structural features of heterojunction, TEM was employed to observe BiVO 4 as opaque structures dispersed on large semi-transparent g-C 3 N 4 surface (Figure. 4a). To analyse particle size, Image J software was used, scaling at 500 nm the particle sizes ranging from 96 to 234 nm (Figure. 4b and c). The spacing between adjacent lattice fringes was measured, which was 0.214 nm aligning with the (002) plane of g-C 3 N 4 , while 0.308 nm matched up with the (121) plane of m-BiVO 4 and 0.269 nm for (200) plane of t-BiVO 4 respectively [ 37 , 38 ] (Fig. 4 d). The SAED patterns revealed diffused rings this shows composite as a polycrystalline nature and irregular bright spots, implying visual indication of the effective coupling of the two semiconductors (Fig. 4 e). These results are reliable with PXRD data. Finally, the EDS spectrum confirms the presence of Bi, V, O, C and N (Fig. 4 f). 3.2. Optical response and composition analysis UV-Visible DRS spectra of BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 were shown in Figure (5 a-e). All the prepared samples are active in the visible light region and the band gap values are determined using the Kubelka-Munk equation by drawing a tangent energy versus [F(R ∞ )hυ] 1/2 . The calculated band gap values for BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 are 2.10, 2.88, 1.87, 2.02 and 2.07 eV, respectively. The deconvoluted XPS spectrum of C 1s has two peaks located at 284.70 and 286.50 eV is assigned C-C bond and the other peak corresponds to C-N group (Fig. 6 a). The N 1s spectrum (Fig. 6 b) shows peaks at 398.5 eV, 399.9 eV, 401.2 eV, and 404.1 eV, attributed to sp²-bonded nitrogen in C = N (pyridinic N), N-(C) 3 (graphitic N), bridging N in heptazine units, and π-excitations, respectively for g-C 3 N 4 [ 39 ]. The Bi4f spectra exhibit doublets at 159.57 and 164.87 eV, indicating the Bi 4f 7/2 and Bi 4f 5/2 (Fig. 6 c), respectively. The 5.44 eV gap between the two binding energies (B. E) indicates that Bi is in the + 3 oxidation state. The split peaks of V2p at 517.37 eV and 524.57 eV correspond to V2p 3/2 and V2p 1/2 , respectively, confirming the presence of a V + 5 oxidation state in BiVO 4 (Fig. 6 d). The two peaks at 529.50 and 531 eV were ascribed to the Bi–O bonds and –OH groups formed on the surface of the g-C 3 N 4 (Fig. 6 e). 3.3. Charge transfer analysis The prepared electrodes interfacial charge-hole separation effect was further described by EIS measurements. Improved interfacial charge migration mobility and reduced solid state layer resistance are revealed by the smaller arc radius on the EIS spectra. Figure 7 a shows Nyquist plots of the BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6. BVG-1 exhibited the smallest semicircle in the mic frequency region compared to BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6, indicating its faster interfacial charge transfer. Transient photocurrent measurements were performed over several on and off cycles to understand the photoexcited electrons generation and transfer efficiency of electron-hole pairs in BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6. As indicated in the Fig. 7 b, photocurrent density was higher than those of the prepared catalysts, showing that the photo-induced holes and electrons were promptly transferred to the electrolyte and substrate, respectively. Better electron and hole transport, a lower recombination rate, and increased charge collection are the causes for the BVG-1 electrode stronger responsiveness. PL measurements were also performed for BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 shown in Fig. 7 c. The peak centered at 487 nm corresponds to the charge transfer between VB to CB in the prepared photocatalysts. On the other hand, the peak at 533 nm could be due to the recombination of photogenerated charge carriers in the g-C 3 N 4 or BiVO 4 [ 40 ]. The lower PL intensity for BGV-1 sample implies lesser recombination of photogenerated charge carriers. the intensity of all the peaks decreases in the following order: BiVO 4 > g-C 3 N 4 > BGV-3 > BGV-6 > BGV-1. An increase in the BiVO 4 content is likely to introduce more defects and grain boundaries and might hinder charge separation, thereby PL intensity are become stronger in case of BGV-3 and BGV-6. The M-S plot was measured under dark conditions to determine the flat band potential. Flat band potentials found to be -0.316, -0.758, 0.297, 0.284 and − 0.05 V for BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 electrodes, respectively (Fig. 7 d and e). This confirms the co-existence of BiVO 4 and g-C 3 N 4 electrode interface, the built-in electric field is due to electron transfer from BiVO 4 to g-C 3 N 4 and improves the separation of photogenerated electron-hole pairs and finally triggers the photocatalytic activity. The CB and VB potentials of BiVO 4 and g-C 3 N 4 are predicted by comparing the results from M-S plot and band gap values (Eqs. 1 and 2). $$\:{E}_{CB}={E}_{FB\:}-0.1\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\left(1\right)$$ $$\:{E}_{VB}={\text{E}}_{\text{C}\text{B}}+{E}_{g}\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\left(2\right)$$ where E VB and E CB are defined as VB and CB edge potentials, E FB is the flat-band potential, and Eg is the band gap energy of the semiconductor. The E CB of BiVO 4 and g-C 3 N 4 was calculated to be + 0.193 and − 0.39 eV/RHE, and E VB was estimated to be + 2.51 and 2.48 eV/RHE, Furthermore, E CB and E VB were calculated (Table S1 ). 3.4. Photocatalytic activity The photocatalytic performance of BiVO 4 , g-C 3 N 4 , BVG-1, BVG-3 and BVG-6 catalysts was evaluated for the degradation of BCG under visible light illumination for 90 min (Fig. 8 a). For BiVO 4 and g-C 3 N 4 the photodegradation increased considerably, reaching up to 53.56 and 50.31%. In addition, BVG-1, BVG-3 and BVG-6 systems showed a greater photocatalytic behaviour than BiVO 4 and g-C 3 N 4 . In particular, the highest degradation efficiency was raised to 92.62% by BVG-1. It is observed that the rise in the content of BiVO 4 the photocatalytic activity. This may be due to the accumulation of a higher content of BiVO 4 on the surface of g-C 3 N 4 , thus reducing the active sites, resulting in lower degradation efficiency. The increased activity of BVG-1 in comparison to other photocatalysts is supported by the rate constant and photonic efficiency (Table 1 ). The Higher activity of the BVG-1 is due to i) reduced recombination of photogenerated charge carriers. ii) enhanced visible light absorption iii) lower resistance and lesser emission collectively contribute to a more efficient photocatalytic process. BVG-1 was excited by visible light to produce photogenerated electrons (CB) and holes (VB). Further generates the · O 2 − , · OH, · OOH reactive species directly involved in the degradation of BCG (Eqs. 3–7) BiVO 4 / g-C 3 N 4 + hν → BiVO 4 / g-C 3 N 4 (h + + e − ) (3) BiVO 4 (h + ) + H 2 O → BiVO 4 + H + + · OH (4) g-C 3 N 4 (e − ) + O 2 → g-C 3 N 4 + · O 2 ‾ (5) H + + · O 2 ‾ → · OOH (6) BCG · + + · OH + · O 2 ‾ → Degraded products (7) 3.5. Photocatalytic performance of BiVO 4 /g-C 3 N 4 S-scheme heterojunction mechanism. The interfacial charge transport between BiVO 4 and g-C 3 N 4 was examined using a computational study based on DFT. The work functions give information about the band alignments and charge transfer direction in the heterojunction. The following equation was used to compute the work functions of BiVO 4 and g-C 3 N 4 .[ 41 , 42 ] $$\:{\phi\:}\:={E}_{vac}-{E}_{F}\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\left(8\right)$$ where E F stands for the energy of the Fermi level and E vac for the energy of the vacuum level. In BVG-, the calculated work function of g-C 3 N 4 and BiVO 4 were found to be 4.42 and 5.12 eV and the Fermi level is -4.69 eV and − 5.4 eV, respectively (Fig. 8 c and d. Based on the band energy levels of BiVO 4 and g-C 3 N 4 possible mechanism for the degradation of BCG is illustrated in Scheme 1 . The VB and CB of BiVO 4 are located at 2.51 eV and 0.19 eV vs. RHE, respectively, and for g-C 3 N 4 , VB and CB are situated at 2.48 eV and − 0.39 eV vs. RHE, respectively. The VB of BiVO 4 is slightly lower than the VB of g-C 3 N 4 . Upon illumination, both the semiconductors were excited and generated electron-hole pairs, and electrons from the CB of BiVO 4 are spontaneously transferred to the VB of g-C 3 N 4 due to the difference in the energy levels, creating positively charged BiVO 4 and negatively charged g-C 3 N 4 . An inner electric field at the interface of BiVO 4 /g-C 3 N 4 could be expected to be built. CB of g-C 3 N 4 was more negative than the redox potentials (O 2 / ·O 2 − = -0.33 V vs RHE). Hence, g-C 3 N 4 can drive O 2 reduction to superoxide radicals (·O 2 − ) and BiVO 4 can drive water anion oxidation to hydroxyl radicals (·OH). Therefore, based on the band edge positions, BiVO 4 /g-C 3 N 4 follows a S-scheme mechanism. In an S-scheme heterojunction, photogenerated electrons from the CB of BiVO 4 recombine with VB holes of g-C 3 N 4, preserving the strong redox abilities the generation of active species contributes to the improved photocatalysis. A high BiVO 4 amount causes particle agglomeration, which decreases surface area and active sites. It also prevents light from reaching the more active component, which lowers the utilization of light overall which is further supported by PL technique.. On the other hand, a higher g-C 3 N 4 content and a lower BiVO 4 content enhance light absorption, producing more electron-hole pairs and lowering recombination, these results are consistent with the electrochemical study. Improved charge carrier separation and redox potential of the photoexcited electrons and holes are achieved by tuning the band locations to generate an S-scheme heterojunction with a lower quantity of BiVO 4 that benefits from its oxidation capacity. When H 2 O 2 was added to the reaction system, the rate at which BCG degraded significantly increased. H 2 O 2 and BVG-1 together may accelerate the color removal dye. The surface adsorption of contaminants, however, limits the quantity of BCG dye molecules that are decolorized. The heterostructure trapping/detrapping oxidation states of Bi 3+ and V 5+ affect the generation of ·OH, and when ·OH intern interacts with H 2 O 2 , ·OOH is produced (Eq. 6–8). On the other hand, a combination of BVG-1 with EDTA, IPA and p-BQ decreases photocatalytic degradation due to trapping of h + , · OH, and · O 2 ‾ (Eq. 9–12). Figure 8 b reveals that · OH radicals played a crucial role in the degradation of BCG. BiVO 4 (h + ) + H 2 O 2 → · OH + OH‾ + BiVO 4 (9) g-C 3 N 4 (e − ) + H 2 O 2 → · OH + OH‾ + g-C 3 N 4 (10) H 2 O 2 + · OH → · OOH + H 2 O (11) BiVO 4 / g-C 3 N 4 (e − + h + ) + · OH + IPA → IPA + + OH‾ + BiVO 4 / g-C 3 N 4 (12) Table 1 Percentage and rate constant values for the degradation of BCG using 1) BiVO 4, 2) g-C 3 N 4 , 3) BVG-1, 4) BVG-2 and 5) BVG-3 catalysts at 90 min. Sl No Catalysts % Degradation Rate Constant min − 1 x10 − 3 Photonic efficiency (10 − 8 ) 1 BiVO 4 53.56 0.0081 7.11 2 g-C 3 N 4 50.31 0.0068 6.38 3 BVG-1 92.62 0.0210 10.48 4 BVG-2 80.77 0.0159 9.72 5 BVG-3 75.55 0.0142 9.33 6 BVG-1 with H 2 O 2 98.92 0.0359 11.25 4. Conclusion In comparison to pure BiVO 4 and g-C 3 N 4 , the as-prepared g-C 3 N 4 /BiVO 4 composites shown higher photocatalytic activity for the degradation of BCG under visible light. The synthesized BiVO 4 and g-C 3 N 4 samples exhibit both tetragonal and monoclinic phases. This study has examined the optimization of the g-C 3 N 4 weight ratio as well as BiVO 4 . The g-C 3 N 4 peak vanished in the g-C 3 N 4 /BiVO 4 due to the crystallinity of BiVO 4 . BVG-1 is more beneficial than BVG-3 and BVG-6 because it exhibits a slightly larger band gap, reduced resistance, and lowered photoluminescence intensity. In addition to the extended lifespan of the photo-excited charge carrier compared to pure BiVO 4 and g-C 3 N 4 , the BiVO 4 /g-C 3 N 4 sample allows for the efficient separation of more electron–hole pairs. The S-scheme charge transfer mechanism of g-C 3 N 4 /BiVO 4 composites, which is generated by the combined effects of BiVO 4 and g-C 3 N 4 , results in notable photocatalytic activity. Declarations Conflict of interest All the Authors declare no conflict of interest Author Contribution Conceptualization: Pooja Mohan and Prathibha CP; Methodology: Pooja Mohan; Formal analysis and investigation: Dr Srinivas M and Dr Sakthivel K ; Writing - original draft preparation: Prathibha C P, Rajesh B M ; Writing - review and editing: Dr Srinivas M and Dr S Girish Kumar; Supervision: Dr Srinivas M. Acknowledgement The authors acknowledge the Department of Chemistry, School of Applied Sciences, REVA University, Bengaluru (RU:EST:CH:2022/21) and RVCE NVIDIA GPU facility for DFT calculations. Data Availability All the Data has been included in the manuscript References Asahi R, Morikawa T, Ohwaki T, et al (2001) Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides. Science 293:269–271. https://doi.org/10.1126/science.1061051 Fu X, Kong Y, Wang M, et al (2024) MXene derived Ti 3 C 2 /TiO 2 /Ag persistent photocatalyst with enhanced electron storage capacity for round-the-clock degradation of organic pollutant. Journal of Colloid and Interface Science 656:233–240. https://doi.org/10.1016/j.jcis.2023.11.079 Cheng H, Huang B, Lu J, et al (2010) Synergistic effect of crystal and electronic structures on the visible-light-driven photocatalytic performances of Bi 2 O 3 polymorphs. Phys Chem Chem Phys 12:15468–15475. https://doi.org/10.1039/C0CP01189D Li F, Kang Y, Chen M, et al (2016) Photocatalytic degradation and removal mechanism of ibuprofen via monoclinic BiVO 4 under simulated solar light. Chemosphere 150:139–144. https://doi.org/10.1016/j.chemosphere.2016.02.045 Gerand B, Nowogrocki G, Guenot J, Figlarz M (1979) Structural study of a new hexagonal form of tungsten trioxide. Journal of Solid State Chemistry 29:429–434. https://doi.org/10.1016/0022-4596(79)90199-3 Sleight AW, Chen H -y., Ferretti A, Cox DE (1979) Crystal growth and structure of BiVO 4 . Materials Research Bulletin 14:1571–1581. https://doi.org/10.1016/0025-5408(72)90227-9 Tokunaga S, Kato H, Kudo A (2001) Selective Preparation of Monoclinic and Tetragonal BiVO 4 with Scheelite Structure and Their Photocatalytic Properties. Chem Mater 13:4624–4628. https://doi.org/10.1021/cm0103390 Kim TW, Choi K-S (2014) Nanoporous BiVO 4 Photoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water Splitting. Science 343:990–994. https://doi.org/10.1126/science.1246913 Saison T, Chemin N, Chanéac C, et al (2015) New Insights Into BiVO 4 Properties as Visible Light Photocatalyst. J Phys Chem C 119:12967–12977. https://doi.org/10.1021/acs.jpcc.5b01468 Shi W, Yan Y, Yan X (2013) Microwave-assisted synthesis of nano-scale BiVO 4 photocatalysts and their excellent visible-light-driven photocatalytic activity for the degradation of ciprofloxacin. Chemical Engineering Journal 215–216:740–746. https://doi.org/10.1016/j.cej.2012.10.071 Tan G, Zhang L, Ren H, et al (2013) Effects of pH on the Hierarchical Structures and Photocatalytic Performance of BiVO 4 Powders Prepared via the Microwave Hydrothermal Method. ACS Appl Mater Interfaces 5:5186–5193. https://doi.org/10.1021/am401019m Khan I, Ali S, Mansha M, Qurashi A (2017) Sonochemical assisted hydrothermal synthesis of pseudo-flower shaped Bismuth vanadate (BiVO 4 ) and their solar-driven water splitting application. Ultrasonics Sonochemistry 36:386–392. https://doi.org/10.1016/j.ultsonch.2016.12.014 Liu H, Hou H, Gao F, et al (2016) Tailored Fabrication of Thoroughly Mesoporous BiVO 4 Nanofibers and Their Visible-Light Photocatalytic Activities. ACS Appl Mater Interfaces 8:1929–1936. https://doi.org/10.1021/acsami.5b10086 Lv C, Sun J, Chen G, et al (2017) Organic salt induced electrospinning gradient effect: Achievement of BiVO 4 nanotubes with promoted photocatalytic performance. Applied Catalysis B: Environmental 208:14–21. https://doi.org/10.1016/j.apcatb.2017.02.058 Liu C, Su J, Zhou J, Guo L (2016) A Multistep Ion Exchange Approach for Fabrication of Porous BiVO 4 Nanorod Arrays on Transparent Conductive Substrate. ACS Sustainable Chem Eng 4:4492–4497. https://doi.org/10.1021/acssuschemeng.6b00971 García-Pérez UM, Martínez-de la Cruz A, Sepúlveda-Guzmán S, Peral J (2014) Low-temperature synthesis of BiVO 4 powders by Pluronic-assisted hydrothermal method: Effect of the surfactant and temperature on the morphology and structural control. Ceramics International 40:4631–4638. https://doi.org/10.1016/j.ceramint.2013.09.002 Hojamberdiev M, Zhu G, Kadirova ZC, et al (2015) Morphology-controlled growth of BiVO 4 crystals by hydrothermal method assisted with ethylene glycol and ethylenediamine and their photocatalytic activity. Materials Chemistry and Physics 165:188–195. https://doi.org/10.1016/j.matchemphys.2015.09.015 Ho-Kimura S, Moniz SJA, Handoko AD, Tang J (2014) Enhanced photoelectrochemical water splitting by nanostructured BiVO 4 –TiO 2 composite electrodes. J Mater Chem A 2:3948–3953. https://doi.org/10.1039/C3TA15268E Zhao K, Zhang Z, Feng Y, et al (2020) Surface oxygen vacancy modified Bi 2 MoO 6 /MIL-88B(Fe) heterostructure with enhanced spatial charge separation at the bulk & interface. Applied Catalysis B: Environmental 268:118740. https://doi.org/10.1016/j.apcatb.2020.118740 Zhang L, Zhang J, Yu H, Yu J (2022) Emerging S-Scheme Photocatalyst. Advanced Materials 34:2107668. https://doi.org/10.1002/adma.202107668 Xu F, Meng K, Cheng B, et al (2020) Unique S-scheme heterojunctions in self-assembled TiO 2 /CsPbBr 3 hybrids for CO 2 photoreduction. Nat Commun 11:4613. https://doi.org/10.1038/s41467-020-18350-7 Ge H, Xu F, Cheng B, et al (2019) S-Scheme Heterojunction TiO 2 /CdS Nanocomposite Nanofiber as H 2 -Production Photocatalyst. ChemCatChem 11:6301–6309. https://doi.org/10.1002/cctc.201901486 Yang Y, Cheng B, Yu J, et al (2023) TiO 2 /In 2 S 3 S-scheme photocatalyst with enhanced H 2 O 2 -production activity. Nano Res 16:4506–4514. https://doi.org/10.1007/s12274-021-3733-0 zhang T, Maihemllti M, Okitsu K, et al (2021) In situ self-assembled S-scheme BiOBr/pCN hybrid with enhanced photocatalytic activity for organic pollutant degradation and CO 2 reduction. Applied Surface Science 556:149828. https://doi.org/10.1016/j.apsusc.2021.149828 Xia P, Cao S, Zhu B, et al (2020) Designing a 0D/2D S-Scheme Heterojunction over Polymeric Carbon Nitride for Visible-Light Photocatalytic Inactivation of Bacteria. Angewandte Chemie International Edition 59:5218–5225. https://doi.org/10.1002/anie.201916012 Zhou L, Li Y, Yang S, et al (2021) Preparation of novel 0D/2D Ag2WO4/WO3 Step-scheme heterojunction with effective interfacial charges transfer for photocatalytic contaminants degradation and mechanism insight. Chemical Engineering Journal 420:130361. https://doi.org/10.1016/j.cej.2021.130361 Ganeshbabu M, Kannan N, Venkatesh PS, et al (2020) Synthesis and characterization of BiVO 4 nanoparticles for environmental applications. RSC Adv 10:18315–18322. https://doi.org/10.1039/D0RA01065K Kalidasan K, Mallapur S, Kumar SG (2024) Pivotal role of surface and bulk Gd species in WO3 to promote Type-II charge carrier transfer pathways in Gd-WO3/g-C3N4 heterojunction photocatalyst. Journal of Environmental Chemical Engineering 12:113054 Dabodiya TS, Selvarasu P, Murugan AV (2019) Tetragonal to Monoclinic Crystalline Phases Change of BiVO4 via Microwave-Hydrothermal Reaction: In Correlation with Visible-Light-Driven Photocatalytic Performance. Inorg Chem 58:5096–5110. https://doi.org/10.1021/acs.inorgchem.9b00193 Zou Y, Lu M, Jiang Z, et al (2021) Hydrothermal synthesis of Zn-doped BiVO4 with mixed crystal phase for enhanced photocatalytic activity. Optical Materials 119:111398. https://doi.org/10.1016/j.optmat.2021.111398 Babu P, Mohanty S, Naik B, Parida K (2019) Serendipitous Assembly of Mixed Phase BiVO4 on B-Doped g-C3N4: An Appropriate p–n Heterojunction for Photocatalytic O2 evolution and Cr(VI) reduction. Inorg Chem 58:12480–12491. https://doi.org/10.1021/acs.inorgchem.9b02309 Dabodiya TS, George T, Vadivel Murugan A (2023) Enhanced Solar-Photo(Electro)catalysis of Microwave-Hydrothermal Synthesized BiVO4, ms-BiVO4/Reduced Graphene Oxide/Ag3PO4 Nanohybrid: Crystalline Phase-Dependent Interfacial Charge Carrier Dynamics. Energy Technology 11:2201099. https://doi.org/10.1002/ente.202201099 Li W, Chen Q, Zhong Q (2020) One-pot fabrication of mesoporous g-C3N4/NiS co-catalyst counter electrodes for quantum-dot-sensitized solar cells. J Mater Sci 55:10712–10724. https://doi.org/10.1007/s10853-020-04672-w Zhong K, Feng J, Gao H, et al (2019) Fabrication of BiVO4@g-C3N4(100) heterojunction with enhanced photocatalytic visible-light-driven activity. Journal of Solid State Chemistry 274:142–151. https://doi.org/10.1016/j.jssc.2019.03.022 Zhang Z, Wang M, Cui W, Sui H (2017) Synthesis and characterization of a core–shell BiVO4@g-C3N4 photo-catalyst with enhanced photocatalytic activity under visible light irradiation. RSC Adv 7:8167–8177. https://doi.org/10.1039/C6RA27766G Xie Q, He W, Liu S, et al (2020) Bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalysts toward artificial carbon cycling. Chinese Journal of Catalysis 41:140–153. https://doi.org/10.1016/S1872-2067(19)63481-9 Chen F, Zhang X, Tang Y, et al (2020) Facile and rapid synthesis of a novel spindle-like heterojunction BiVO4 showing enhanced visible-light-driven photoactivity. RSC Adv 10:5234–5240. https://doi.org/10.1039/C9RA07891F Li C, Che H, Liu C, et al (2019) Facile fabrication of g-C3N4 QDs/BiVO4 Z-scheme heterojunction towards enhancing photodegradation activity under visible light. Journal of the Taiwan Institute of Chemical Engineers 95:669–681. https://doi.org/10.1016/j.jtice.2018.10.011 Zalfani M, Schueren B van der, Hu Z-Y, et al (2015) Novel 3DOM BiVO4/TiO2 nanocomposites for highly enhanced photocatalytic activity. J Mater Chem A 3:21244–21256. https://doi.org/10.1039/C5TA00783F Li Y, Qin T, Chen W, et al (2022) Construction of a Switchable g-C3N4/BiVO4 Heterojunction from the Z-Scheme to the Type II by Incorporation of Pyromellitic Diimide. Crystal Growth & Design 22:1645–1653. https://doi.org/10.1021/acs.cgd.1c01163 Chen Y, Ma X, Li D, et al (2017) Mechanism of enhancing visible-light photocatalytic activity of BiVO 4 via hybridization of graphene based on a first-principles study. RSC Advances 7:4395–4401. https://doi.org/10.1039/C6RA25721F Wang J, Wang G, Cheng B, et al (2021) Sulfur-doped g-C3N4/TiO2 S-scheme heterojunction photocatalyst for Congo Red photodegradation. Chinese Journal of Catalysis 42:56–68. https://doi.org/10.1016/S1872-2067(20)63634-8 Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformation.docx scheme1.jpg Scheme 1. Charge separation and transfer in the BiVO 4 /g-C 3 N 4 composite under solar-light irradiation. Cite Share Download PDF Status: Published Journal Publication published 11 Jan, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7580004","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":518295275,"identity":"c1121c95-63c7-4ff5-9bb8-cf15b4b50e3a","order_by":0,"name":"Pooja Mohan","email":"","orcid":"","institution":"REVA University","correspondingAuthor":false,"prefix":"","firstName":"Pooja","middleName":"","lastName":"Mohan","suffix":""},{"id":518295277,"identity":"db95c74c-6f46-4033-91f5-10aa9b4c5668","order_by":1,"name":"Srinivas Mallapur","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5klEQVRIiWNgGAWjYFACxgaGBDCD+QBUJIEBKkJQCxtMHUEtcMBjgNCCD8jPPtz24GGbnT2D2JlvHz622THws+cYMDzcgVuLwbnEdoPEtuTEBunczTNntiUzSPa8MWBIPINHCw9jm0TCGeYEBqAWZp4zzAwGN4C2JLbhcVgPWEu9PYN0zmPmP2fqGewJaWE4A9JScZixQTqHmZmh4jCDgQQBLQYQLccT26TTjBl7Ko7zSJx5VnAAv8PYn0n+MKi255dOfswAZMjxtydvfPgTn8NggA1K84CIA0RoGAWjYBSMglGABwAArBxI9EP3t0QAAAAASUVORK5CYII=","orcid":"","institution":"REVA University","correspondingAuthor":true,"prefix":"","firstName":"Srinivas","middleName":"","lastName":"Mallapur","suffix":""},{"id":518295278,"identity":"22d573f3-f4ae-400c-b5c6-d6a3655277f0","order_by":2,"name":"C P Prathibha","email":"","orcid":"","institution":"REVA University","correspondingAuthor":false,"prefix":"","firstName":"C","middleName":"P","lastName":"Prathibha","suffix":""},{"id":518295280,"identity":"b6dc4264-7241-4efa-894f-9879c3f30e51","order_by":3,"name":"Rajesh B M","email":"","orcid":"","institution":"RV College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Rajesh","middleName":"B","lastName":"M","suffix":""},{"id":518295281,"identity":"6b198768-9f8c-4968-a6bc-86d38cabb15d","order_by":4,"name":"Sakthivel Kandaiah","email":"","orcid":"","institution":"REVA University","correspondingAuthor":false,"prefix":"","firstName":"Sakthivel","middleName":"","lastName":"Kandaiah","suffix":""},{"id":518295284,"identity":"324866e2-bc83-4294-9045-259f561f67ac","order_by":5,"name":"S. Girish Kumar","email":"","orcid":"","institution":"RV College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"S.","middleName":"Girish","lastName":"Kumar","suffix":""}],"badges":[],"createdAt":"2025-09-10 07:38:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7580004/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7580004/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10854-025-16555-4","type":"published","date":"2026-01-11T15:59:24+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":92069173,"identity":"4ecbbd0c-9ba0-4311-9773-de878b4c5e63","added_by":"auto","created_at":"2025-09-24 09:30:39","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11489705,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/58b87fbcbaa3f9c46dc7d60a.docx"},{"id":92069128,"identity":"17ff655a-bb03-4bed-9ef0-c07f465ae4ec","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7216,"visible":true,"origin":"","legend":"","description":"","filename":"f86ab8a1793e410f99ebafb5b7317e63.json","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/e1da08672f70e48a77ab0713.json"},{"id":92069130,"identity":"9f104b5a-67bd-438e-bc14-26fc4189518a","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":20768,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/febf1bdcd634d0bb85027149.docx"},{"id":92069136,"identity":"adaf09fd-89ec-47ff-b65a-7806fe9bc27f","added_by":"auto","created_at":"2025-09-24 09:30:33","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":115408,"visible":true,"origin":"","legend":"","description":"","filename":"f86ab8a1793e410f99ebafb5b7317e631enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/9d5a3fbf0e35a1269df2ebfd.xml"},{"id":92069133,"identity":"ae47124f-43ab-4435-b0c5-435d8069026a","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"emf","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":361192,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.emf","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/87c895f96c47d4425cf09f5c.emf"},{"id":92070184,"identity":"99795374-03b9-4d4a-9f71-d69770701413","added_by":"auto","created_at":"2025-09-24 09:38:30","extension":"emf","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":135816,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.emf","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/ed262f3b261507f23540a779.emf"},{"id":92069124,"identity":"1ba6eaf5-14fa-4a58-bb1b-9266e3618997","added_by":"auto","created_at":"2025-09-24 09:30:30","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3575211,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/e8390c04784f1f5cb75606d4.png"},{"id":92069112,"identity":"e52e987f-ab5e-44f5-b469-539aeed869d3","added_by":"auto","created_at":"2025-09-24 09:30:28","extension":"jpeg","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":524957,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/4265a2e0c8b34485ae88eb27.jpeg"},{"id":92069134,"identity":"f9e76b0f-900e-4ef9-978c-a5c264728000","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"jpeg","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":665164,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/0d952b75f68a2c5768b0ae09.jpeg"},{"id":92069126,"identity":"aaa86a22-c5a9-4b04-9684-601deb0ff188","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"jpeg","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":679031,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/203e8e028e767b25992b34b8.jpeg"},{"id":92070205,"identity":"7b6c2cf7-a2b6-45d8-a0a9-b164edcb8fd0","added_by":"auto","created_at":"2025-09-24 09:38:36","extension":"jpeg","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3254,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/db858109c4ce3b50acf65d82.jpeg"},{"id":92069162,"identity":"13c96220-ae54-48c7-a8d3-31541f1713f1","added_by":"auto","created_at":"2025-09-24 09:30:38","extension":"jpeg","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":142041,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/9bef7aed7a91b76f8130e404.jpeg"},{"id":92069127,"identity":"5be19f37-25ec-4f73-acb9-e8e6b0b558a2","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"jpeg","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":57160,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/f59296099a0c48370736397b.jpeg"},{"id":92069148,"identity":"0c410e2f-2d5a-47c9-b7d3-669e68139e3d","added_by":"auto","created_at":"2025-09-24 09:30:35","extension":"jpeg","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":166562,"visible":true,"origin":"","legend":"","description":"","filename":"groupimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/c9d8d3de38321b23241fdc78.jpeg"},{"id":92069119,"identity":"7f83a0e5-462b-46c5-9cec-60ead3f57435","added_by":"auto","created_at":"2025-09-24 09:30:30","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":26047,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/7d3b30c374787c67040d6bcc.png"},{"id":92069165,"identity":"81d8bad1-17bc-4cdc-b657-2c8d67ca5597","added_by":"auto","created_at":"2025-09-24 09:30:38","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":27185,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/5c7d998152fbc739a54df155.png"},{"id":92069150,"identity":"54b82e1e-cdb9-4684-a946-d1373bb2dc0c","added_by":"auto","created_at":"2025-09-24 09:30:36","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":388257,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/b3a8c49cc8015a9a22edd0a0.png"},{"id":92069107,"identity":"0c5019fa-238b-4918-84d9-0f685721a7b4","added_by":"auto","created_at":"2025-09-24 09:30:28","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83293,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/1fb19f5f1bc895fcfed85357.png"},{"id":92069125,"identity":"9d6570bd-5609-4fcb-aa4e-24c8828b4d59","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":119277,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/a7ebd14b72f34328714c8302.png"},{"id":92069144,"identity":"76e621db-6a0e-42bf-aa5b-657efa6f1780","added_by":"auto","created_at":"2025-09-24 09:30:34","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":111368,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/3b3047419057af60a9225580.png"},{"id":92069141,"identity":"b97817bb-b205-4de6-9516-71c60ee23c62","added_by":"auto","created_at":"2025-09-24 09:30:34","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1077,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/d7126de72bf33ff6750d0bbc.png"},{"id":92069105,"identity":"cf16dea5-38b7-4620-9a5d-de72d2435fcb","added_by":"auto","created_at":"2025-09-24 09:30:27","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":24628,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/01469350a682ab1e2ac627d6.png"},{"id":92069109,"identity":"2599b2a0-a035-428f-8729-72c299b6ff14","added_by":"auto","created_at":"2025-09-24 09:30:28","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":20467,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/6fd112228be512b90a4b0e71.png"},{"id":92069121,"identity":"33dec1fb-52a0-497e-8a8a-9cea3cf38474","added_by":"auto","created_at":"2025-09-24 09:30:30","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":70062,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinegroupimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/51261c72602b7d631ab503dc.png"},{"id":92069137,"identity":"5312a25c-138f-40bd-9c67-1715e467dd80","added_by":"auto","created_at":"2025-09-24 09:30:33","extension":"xml","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":115558,"visible":true,"origin":"","legend":"","description":"","filename":"f86ab8a1793e410f99ebafb5b7317e631structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/e2306025994c885e258a081d.xml"},{"id":92070204,"identity":"810f040b-3936-4a49-b798-f689454928cf","added_by":"auto","created_at":"2025-09-24 09:38:36","extension":"html","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":119810,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/9f0e4bb8fdae03e6ce99299e.html"},{"id":92069132,"identity":"416efddf-f573-4345-9e15-e6087218518e","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":90338,"visible":true,"origin":"","legend":"\u003cp\u003ePXRD Pattern of 1) BiVO\u003csub\u003e4\u003c/sub\u003e, 2) g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, 3) BVG-1, 4) BVG-3 and 5) BVG-6.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/546752b7900893349d9f990e.jpg"},{"id":92069138,"identity":"a9b43d7d-e95e-4d73-9725-f509a4b0298d","added_by":"auto","created_at":"2025-09-24 09:30:34","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":96254,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e,\u003csub\u003e \u003c/sub\u003eBVG-1, BVG-3 and BVG-6.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/c6417177c72697c5ef9d70a2.jpg"},{"id":92069145,"identity":"16f2f9ca-7daa-4183-b61d-2469f365e47c","added_by":"auto","created_at":"2025-09-24 09:30:35","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":231566,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of (a) BiVO\u003csub\u003e4\u003c/sub\u003e, (b) g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, FESEM images of (c) BVG-1, (d) BVG-3, (e) BVG-6 and (f) EDS mapping of BVG composite.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/fa92db067a707d2eb5bb56da.jpg"},{"id":92069129,"identity":"4f987691-f7f9-41a4-a883-fadff41beeb5","added_by":"auto","created_at":"2025-09-24 09:30:31","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":163460,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003ea and b) TEM images, (c) Particle size distribution, (d) HRTEM image (e) SAED pattern and (f) EDS for BVG-1 composite\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/02a65dd19a59f2443d2593dd.jpg"},{"id":92069114,"identity":"f88c7e76-30cc-4fa9-b4f7-aba1a25cbf63","added_by":"auto","created_at":"2025-09-24 09:30:28","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":88545,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Vis DRS spectra of a) BiVO\u003csub\u003e4\u003c/sub\u003e, b) g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, c) BVG-1, d) BVG-3 and e) BVG-6. The\u003csub\u003e \u003c/sub\u003einset is the Kubelka-Munk plot for the band gap energy calculation.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/c40159bd5dec44b3564b0fd9.jpg"},{"id":92069108,"identity":"af22fd12-593f-4793-a948-598b44d95e52","added_by":"auto","created_at":"2025-09-24 09:30:28","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":106637,"visible":true,"origin":"","legend":"\u003cp\u003eDeconvoluted XPS spectra of\u003cstrong\u003e \u003c/strong\u003e(a) C 1s, (b) N 1s, (c) Bi 4f, (d) V 2p and (e) O 1s of BVG-1.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/2fd9ade3df7ee8bd224b5a59.jpg"},{"id":92070193,"identity":"f15d1835-40a5-421f-bb4f-d307c13743ea","added_by":"auto","created_at":"2025-09-24 09:38:34","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":100769,"visible":true,"origin":"","legend":"\u003cp\u003ea) EIS; b) Photocurrent response; c)\u003cstrong\u003e \u003c/strong\u003ePL spectra for BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6\u003csub\u003e \u003c/sub\u003ecomposite; d and e) M-S plot for BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/d11b368be77eaf9e04601241.jpg"},{"id":92069164,"identity":"93265ff4-9703-4787-b2cd-a854fbffe8ca","added_by":"auto","created_at":"2025-09-24 09:30:38","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":158625,"visible":true,"origin":"","legend":"\u003cp\u003ea)\u003cstrong\u003e \u003c/strong\u003eC/C\u003csub\u003e0\u003c/sub\u003e plot \u003cem\u003evs\u003c/em\u003e time in minutes for degradation of BCG (10 ppm) in the presence of all the prepared catalysts, b) Trapping tests of active species during the degradation of BCG using BVG-1 under light irradiation and c and d) Work function of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4 \u003c/sub\u003eand BiVO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/c052897c47c33e089f686bce.jpg"},{"id":100069439,"identity":"dd0e2efb-66f6-4122-8065-4c0373760d19","added_by":"auto","created_at":"2026-01-12 16:14:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1989089,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/8b49e067-f740-45ec-8aae-6a9cf45612d4.pdf"},{"id":92069152,"identity":"97fad7e8-ffeb-498b-b96c-633646f67903","added_by":"auto","created_at":"2025-09-24 09:30:36","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":20768,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/636bcd8f4ac75bf05b43fec1.docx"},{"id":92069116,"identity":"b591080f-c578-44d1-b6c9-3e209c09c681","added_by":"auto","created_at":"2025-09-24 09:30:29","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":61570,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 1.\u003c/strong\u003e Charge separation and transfer in the BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4 \u003c/sub\u003ecomposite under solar-light irradiation.\u003c/p\u003e","description":"","filename":"scheme1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7580004/v1/d5e988ef3610bd29e68670ef.jpg"}],"financialInterests":"No competing interests reported.","formattedTitle":"Binary composites of (m-t) BiVO 4 /g-C 3 N 4 as an efficient S-scheme photocatalyst for bromocresol green degradation under visible light","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eResearchers have focused a lot of attention on semiconductor photocatalysts in recent decades because of their ability to remove organic dyes from contaminated water.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] Among the variety of visible light responsive catalysts, the Bismuth series photocatalysts have garnered a lot of interest because of their distinct physical and chemical characteristics as well as their broad spectrum of light absorption regions.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Graphitic carbon nitride (g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e), bismuth trioxide (Bi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e), tungsten oxide (WO\u003csub\u003e3\u003c/sub\u003e), cadmium sulfide (CdS), and bismuth vanadate (BiVO\u003csub\u003e4\u003c/sub\u003e) are well-known visible-light photocatalysts with polymorphs that have attracted a lot of interest due to their crystalline phase-dependent photocatalytic efficacy.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] Zircon tetragonal (zt-BiVO\u003csub\u003e4\u003c/sub\u003e), tetragonal (ts-BiVO\u003csub\u003e4\u003c/sub\u003e), orthorhombic (o-BiVO\u003csub\u003e4\u003c/sub\u003e), and monoclinic (m-BiVO\u003csub\u003e4\u003c/sub\u003e) scheelite are a few polymorphs of BiVO\u003csub\u003e4\u003c/sub\u003e.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] Among these, polymorphs, monoclinic BiVO\u003csub\u003e4\u003c/sub\u003e has the best photo harvesting property due to the relatively narrow band gap (2.4 eV), whereas tetragonal BiVO\u003csub\u003e4\u003c/sub\u003e with 2.9 eV band gap mainly reposes to UV light stimulation.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] The BiVO\u003csub\u003e4\u003c/sub\u003e can be prepared by different routings, such as microwave\u0026ndash;assisted synthesis,[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] ultrasonic\u0026ndash;assisted process,[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] electrospun,[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] multistep ion exchange approach,[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] hydrothermal method[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] and metal\u0026ndash;organic decomposition.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] These techniques have been used to create BiVO\u003csub\u003e4\u003c/sub\u003e in the shapes of stars, tubes, flowers, sheets, spheres, leaves, and fibers. Narrow band gap and non-toxicity are features of n-type monoclinic BiVO\u003csub\u003e4\u003c/sub\u003e, a typical bismuth oxide. However, a single photocatalyst cannot ensure both strong oxidation and reduction capabilities by having an active visible light response, and vice versa, making it very hard to achieve both of these requirements at once. Furthermore, the low conduction band potential of BiVO\u003csub\u003e4\u003c/sub\u003e hinders the transmission of photogenerated electron-hole pairs and makes it challenging to capture photogenerated electrons, which contributes to the low yield of photogenerated electrons. This suggests that BiVO\u003csub\u003e4\u003c/sub\u003e could be a material of promise for creating composites with significantly enhanced photocatalytic activity. Consequently, efficient methods for accelerating the separation of photogenerated electron-hole pairs need to be developed.\u003c/p\u003e\u003cp\u003eA good substitute for heterojunction fabricating is g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, which has a multilayer structure, is straightforward to regulate, and exhibits chemical stability. Furthermore, the enormous specific surface area and 2D planar conjugate structure of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e allow it to be employed as a huge scaffold for anchoring a variety of platforms. Furthermore, the lamellar structure of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e sets it apart from other organic π-conjugated materials. The energy levels of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e were found to have well-matched overlapping band structures. The combination of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and BiVO\u003csub\u003e4\u003c/sub\u003e can meritoriously prevent the recombination of photogenerated electron-hole pairs and form g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/BiVO\u003csub\u003e4\u003c/sub\u003e heterojunctions with excellent ability to photogenerated electron-hole pair transfer and separation. To realize this goal, effective bulk separation of photogenerated charge carriers within semiconductor photocatalysts is a crucial prerequisite.[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] Moreover, it has been demonstrated that step-scheme (S-scheme) heterojunctions can promote spatial charge separation at the surface level.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] In contrast to conventional Z-scheme photosystems, the S-scheme structure's internal electric field, band bending, and coulombic attraction can enhance photocatalytic performance and encourage charge transfer, for instance, the heterojunctions of CsPbBr\u003csub\u003e3\u003c/sub\u003e/TiO\u003csub\u003e2,\u003c/sub\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] TiO\u003csub\u003e2\u003c/sub\u003e/CdSm,[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] TiO\u003csub\u003e2\u003c/sub\u003e/In\u003csub\u003e2\u003c/sub\u003eS\u003csub\u003e3\u003c/sub\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], BiOBr/C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], CeO\u003csub\u003e2\u003c/sub\u003e/PCN [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] and Ag\u003csub\u003e2\u003c/sub\u003eWO\u003csub\u003e4\u003c/sub\u003e/WO\u003csub\u003e3\u003c/sub\u003e.[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn this work, we report the construction of BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e S-scheme heterojunctions are prepared via a facile solid-state method. The photocatalytic performance of the prepared catalysts was evaluated for the degradation of bromocresol green (BCG). The prominent results were obtained for heterostructures due to the significantly improved light response and interfacial charge transfer efficiency. In addition to increasing the light response range, the coupling of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e semiconductors provide a driving force for the separation and transfer of photo-generated electron-hole pairs. Enhanced photocatalytic activity correlated with rate constant, photonic efficiency and electrochemical measurements were discussed in detail. The trapping experiment was conducted to investigate the role of free radicals during the degradation process.\u003c/p\u003e"},{"header":"2. Experimental procedure","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Materials\u003c/h2\u003e\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eBismuth nitrate pentahydrate Bi(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e.5H\u003csub\u003e2\u003c/sub\u003eO), ammonium meta vanadate (NH\u003csub\u003e4\u003c/sub\u003eVO\u003csub\u003e3\u003c/sub\u003e), ammonium hydroxide (NH\u003csub\u003e4\u003c/sub\u003eOH), hydrogen peroxide (H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e), sodium sulphate (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e), isopropyl alcohol (IPA), para benzoquinone (p-BQ), ethylene diamine tetraacetic acid (EDTA), nitric acid (HNO\u003csub\u003e3\u003c/sub\u003e), Melamine (C\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e6\u003c/sub\u003eN\u003csub\u003e6\u003c/sub\u003e), Bromocresol green (C\u003csub\u003e21\u003c/sub\u003eH\u003csub\u003e14\u003c/sub\u003eBr\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003eS), ethanol and de-ionised water were used during the experiment.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Preparation of BiVO\u003csub\u003e4\u003c/sub\u003e\u003c/h2\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e was prepared by dissolving 3.959 g Bi(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e.5H\u003csub\u003e2\u003c/sub\u003eO and 0.9451 g NH\u003csub\u003e4\u003c/sub\u003eVO\u003csub\u003e3\u003c/sub\u003e in 200 mL of HNO\u003csub\u003e3\u003c/sub\u003e. The resultant mixture was continuously stirred for 2 h to get a homogeneous yellow colour solution. 4M NH\u003csub\u003e4\u003c/sub\u003eOH was slowly added to the mixture to adjust the pH 9, resulting in a yellow-orange colour precipitate and further continued stirring for 1h to form the product. The final product was then dried for 24 hours at 70\u0026deg;C after being centrifuged and washed three times with distilled water and ethanol to get rid of any leftover substances. Further, the product was calcined at 500\u0026deg;C for 5 h in a muffle furnace.[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Preparation of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003c/h2\u003e\u003cp\u003eThe direct heating of Melamine at 550\u0026deg;C for 2 h in a semi-closed alumina crucible, resulting in the g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. A low ramping rate of 10\u0026deg;C was maintained. After cooling down naturally to ambient temperature, the yellow g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e was obtained in powder form.[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Preparation of Heterojunction BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e composites\u003c/h2\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e composites were prepared by mixing a certain amount of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and grinding thoroughly in an agate mortar for 5 minutes, further calcined at 500\u0026deg;C for 2 h. 0.1 g of BiVO\u003csub\u003e4\u003c/sub\u003e mixed with 0.9 g of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e results in the 0.1BiVO\u003csub\u003e4\u003c/sub\u003e/0.9 g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and named as BVG-1 similarly for the 0.3BiVO\u003csub\u003e4\u003c/sub\u003e/0.7 g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and 0.6BiVO\u003csub\u003e4\u003c/sub\u003e/0.4 g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e are designated as BVG-3 and BVG-6 respectively. The characterization details, photoelectrochemical performance and photocatalytic experiment details were amended in the supplementary material S1, S2 and S3.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Structural and morphological analysis\u003c/h2\u003e\u003cp\u003eThe PXRD patterns of BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 were shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. BiVO\u003csub\u003e4\u003c/sub\u003e PXRD peaks at 2θ values 18.9\u0026deg; (110), 28.9\u0026deg; (121), 30.7\u0026deg; (040), 34.6\u0026deg; (200), 35.1\u0026deg; (002), 40.10\u0026deg; (211), 42.4\u0026deg; (015), 45.8\u0026deg; (240), 47.2\u0026deg; (042), 50.21\u0026deg; (220) and 53.3\u0026deg; (161) these planes confirm the monoclinic scheelite structure (JCPDS NO 98-901-2063). The two diffraction peaks at 13.4\u0026deg; (100) and 27.9\u0026deg; (002) confirm the tetragonal phase of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (JCPDS 87-1526).[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] Interestingly, the new peaks at 2θ values 23.4\u0026deg; (200) and 31.9\u0026deg; (112), which is attributed to the zircon tetragonal phase of BiVO\u003csub\u003e4\u003c/sub\u003e (JCPDS-00-014-0133), after integrating with g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e in three heterostructures. These characteristic diffraction peaks confirm that three crystal phases of m-BiVO\u003csub\u003e4\u003c/sub\u003e, (t) BiVO\u003csub\u003e4\u003c/sub\u003e and tetragonal g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e exist in the BVG-1, BVG-3 and BVG-6 composites.[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] The average crystallite size was calculated by using Scherer\u0026rsquo;s formula and the calculated values were ~\u0026thinsp;46.03, 8.92, 40.14, 32.47 and 46.67 nm for BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and BVG-1, BVG-3 and BVG-6, respectively.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the FTIR spectra of BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6. The band at 606 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e represents the Bi\u0026ndash;O bending vibration, while at 760 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponds to V-O includes both symmetric and asymmetric stretching vibrations. The bands at 804 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 871 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e are due to bending modes of the S-triazine unit [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e], peak at 1644 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e representing the sp\u003csup\u003e2\u003c/sup\u003e C\u0026thinsp;=\u0026thinsp;N stretching and bands at 1232 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1327 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 1455 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e representing the aromatic sp\u003csup\u003e3\u003c/sup\u003e C\u0026ndash;N stretching modes. The typical bands of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e show a slight shift in the composites due to the interaction between BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMorphology of pristine BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and three composites of BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e depicted in the SEM images (Figure. 3a-e). Figure. 3a shows that the BiVO\u003csub\u003e4\u003c/sub\u003e had an aggregated morphology [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e], and Figure. 3b depicts the irregular nanosheet morphology of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. Figures\u0026nbsp;(3c-e) displays, that upon increasing the content of BiVO\u003csub\u003e4\u003c/sub\u003e, more aggregation occurs on the layered g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e structure in the composites. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ef shows the EDAX technique confirms the presence of Bi, V, C, N and O atoms of in the BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e composite.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\n\u003cp\u003eTo gain a clear understanding of the structural features of heterojunction, TEM was employed to observe BiVO\u003csub\u003e4\u003c/sub\u003e as opaque structures dispersed on large semi-transparent g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e surface (Figure. 4a). To analyse particle size, Image J software was used, scaling at 500 nm the particle sizes ranging from 96 to 234 nm (Figure. 4b and c). The spacing between adjacent lattice fringes was measured, which was 0.214 nm aligning with the (002) plane of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, while 0.308 nm matched up with the (121) plane of m-BiVO\u003csub\u003e4\u003c/sub\u003e and 0.269 nm for (200) plane of t-BiVO\u003csub\u003e4\u003c/sub\u003e respectively [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed). The SAED patterns revealed diffused rings this shows composite as a polycrystalline nature and irregular bright spots, implying visual indication of the effective coupling of the two semiconductors (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee). These results are reliable with PXRD data. Finally, the EDS spectrum confirms the presence of Bi, V, O, C and N (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Optical response and composition analysis\u003c/h2\u003e\u003cp\u003eUV-Visible DRS spectra of BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 were shown in Figure (5 a-e). All the prepared samples are active in the visible light region and the band gap values are determined using the Kubelka-Munk equation by drawing a tangent energy versus [F(R\u003csub\u003e\u0026infin;\u003c/sub\u003e)hυ]\u003csup\u003e1/2\u003c/sup\u003e. The calculated band gap values for BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 are 2.10, 2.88, 1.87, 2.02 and 2.07 eV, respectively.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe deconvoluted XPS spectrum of C 1s has two peaks located at 284.70 and 286.50 eV is assigned C-C bond and the other peak corresponds to C-N group (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea). The N 1s spectrum (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb) shows peaks at 398.5 eV, 399.9 eV, 401.2 eV, and 404.1 eV, attributed to sp\u0026sup2;-bonded nitrogen in C\u0026thinsp;=\u0026thinsp;N (pyridinic N), N-(C)\u003csub\u003e3\u003c/sub\u003e (graphitic N), bridging N in heptazine units, and π-excitations, respectively for g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. The Bi4f spectra exhibit doublets at 159.57 and 164.87 eV, indicating the Bi 4f\u003csub\u003e7/2\u003c/sub\u003e and Bi 4f\u003csub\u003e5/2\u003c/sub\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec), respectively. The 5.44 eV gap between the two binding energies (B. E) indicates that Bi is in the +\u0026thinsp;3 oxidation state. The split peaks of V2p at 517.37 eV and 524.57 eV correspond to V2p\u003csub\u003e3/2\u003c/sub\u003e and V2p\u003csub\u003e1/2\u003c/sub\u003e, respectively, confirming the presence of a V\u003csup\u003e+\u0026thinsp;5\u003c/sup\u003e oxidation state in BiVO\u003csub\u003e4\u003c/sub\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ed). The two peaks at 529.50 and 531 eV were ascribed to the Bi\u0026ndash;O bonds and \u0026ndash;OH groups formed on the surface of the g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ee).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.3. Charge transfer analysis\u003c/h2\u003e\u003cp\u003eThe prepared electrodes interfacial charge-hole separation effect was further described by EIS measurements. Improved interfacial charge migration mobility and reduced solid state layer resistance are revealed by the smaller arc radius on the EIS spectra. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea shows Nyquist plots of the BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6. BVG-1 exhibited the smallest semicircle in the mic frequency region compared to BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6, indicating its faster interfacial charge transfer.\u003c/p\u003e\u003cp\u003eTransient photocurrent measurements were performed over several on and off cycles to understand the photoexcited electrons generation and transfer efficiency of electron-hole pairs in BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6. As indicated in the Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb, photocurrent density was higher than those of the prepared catalysts, showing that the photo-induced holes and electrons were promptly transferred to the electrolyte and substrate, respectively. Better electron and hole transport, a lower recombination rate, and increased charge collection are the causes for the BVG-1 electrode stronger responsiveness.\u003c/p\u003e\u003cp\u003ePL measurements were also performed for BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ec. The peak centered at 487 nm corresponds to the charge transfer between VB to CB in the prepared photocatalysts. On the other hand, the peak at 533 nm could be due to the recombination of photogenerated charge carriers in the g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e or BiVO\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. The lower PL intensity for BGV-1 sample implies lesser recombination of photogenerated charge carriers. the intensity of all the peaks decreases in the following order: BiVO\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u0026gt;\u0026thinsp;g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u0026gt;\u0026thinsp;BGV-3\u0026thinsp;\u0026gt;\u0026thinsp;BGV-6\u0026thinsp;\u0026gt;\u0026thinsp;BGV-1. An increase in the BiVO\u003csub\u003e4\u003c/sub\u003e content is likely to introduce more defects and grain boundaries and might hinder charge separation, thereby PL intensity are become stronger in case of BGV-3 and BGV-6.\u003c/p\u003e\u003cp\u003eThe M-S plot was measured under dark conditions to determine the flat band potential. Flat band potentials found to be -0.316, -0.758, 0.297, 0.284 and \u0026minus;\u0026thinsp;0.05 V for BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 electrodes, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ed and e). This confirms the co-existence of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e electrode interface, the built-in electric field is due to electron transfer from BiVO\u003csub\u003e4\u003c/sub\u003e to g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and improves the separation of photogenerated electron-hole pairs and finally triggers the photocatalytic activity.\u003c/p\u003e\u003cp\u003eThe CB and VB potentials of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e are predicted by comparing the results from M-S plot and band gap values (Eqs.\u0026nbsp;1 and 2).\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:{E}_{CB}={E}_{FB\\:}-0.1\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\left(1\\right)$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:{E}_{VB}={\\text{E}}_{\\text{C}\\text{B}}+{E}_{g}\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\left(2\\right)$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere E\u003csub\u003eVB\u003c/sub\u003e and E\u003csub\u003eCB\u003c/sub\u003e are defined as VB and CB edge potentials, E\u003csub\u003eFB\u003c/sub\u003e is the flat-band potential, and Eg is the band gap energy of the semiconductor. The E\u003csub\u003eCB\u003c/sub\u003e of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e was calculated to be +\u0026thinsp;0.193 and \u0026minus;\u0026thinsp;0.39 eV/RHE, and E\u003csub\u003eVB\u003c/sub\u003e was estimated to be +\u0026thinsp;2.51 and 2.48 eV/RHE, Furthermore, E\u003csub\u003eCB\u003c/sub\u003e and E\u003csub\u003eVB\u003c/sub\u003e were calculated (Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.4. Photocatalytic activity\u003c/h2\u003e\u003cp\u003eThe photocatalytic performance of BiVO\u003csub\u003e4\u003c/sub\u003e, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, BVG-1, BVG-3 and BVG-6 catalysts was evaluated for the degradation of BCG under visible light illumination for 90 min (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ea). For BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e the photodegradation increased considerably, reaching up to 53.56 and 50.31%. In addition, BVG-1, BVG-3 and BVG-6 systems showed a greater photocatalytic behaviour than BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. In particular, the highest degradation efficiency was raised to 92.62% by BVG-1. It is observed that the rise in the content of BiVO\u003csub\u003e4\u003c/sub\u003e the photocatalytic activity. This may be due to the accumulation of a higher content of BiVO\u003csub\u003e4\u003c/sub\u003e on the surface of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, thus reducing the active sites, resulting in lower degradation efficiency. The increased activity of BVG-1 in comparison to other photocatalysts is supported by the rate constant and photonic efficiency (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The Higher activity of the BVG-1 is due to i) reduced recombination of photogenerated charge carriers. ii) enhanced visible light absorption iii) lower resistance and lesser emission collectively contribute to a more efficient photocatalytic process. BVG-1 was excited by visible light to produce photogenerated electrons (CB) and holes (VB). Further generates the \u003cb\u003e\u0026middot;\u003c/b\u003eO\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, \u003cb\u003e\u0026middot;\u003c/b\u003eOH, \u003cb\u003e\u0026middot;\u003c/b\u003eOOH reactive species directly involved in the degradation of BCG (Eqs.\u0026nbsp;3\u0026ndash;7)\u003c/p\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003eg-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u003cb\u003e+\u003c/b\u003e\u0026thinsp;hν \u0026rarr; BiVO\u003csub\u003e4\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003e g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (h\u003csup\u003e+\u003c/sup\u003e + e\u003csup\u003e\u0026minus;\u003c/sup\u003e) (3)\u003c/p\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e (h\u003csup\u003e+\u003c/sup\u003e)\u0026thinsp;\u003cb\u003e+\u003c/b\u003e\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO \u0026rarr; BiVO\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u003cb\u003e+\u003c/b\u003e\u0026thinsp;H\u003csup\u003e+\u003c/sup\u003e \u003cb\u003e+ \u0026middot;\u003c/b\u003eOH (4)\u003c/p\u003e\u003cp\u003eg-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (e\u003csup\u003e\u0026minus;\u003c/sup\u003e)\u0026thinsp;\u003cb\u003e+\u003c/b\u003e\u0026thinsp;O\u003csub\u003e2\u003c/sub\u003e \u0026rarr; g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e + \u003cb\u003e\u0026middot;\u003c/b\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026oline; (5)\u003c/p\u003e\u003cp\u003eH\u003csup\u003e+\u003c/sup\u003e + \u003cb\u003e\u0026middot;\u003c/b\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026oline; \u0026rarr; \u003cb\u003e\u0026middot;\u003c/b\u003eOOH (6)\u003c/p\u003e\u003cp\u003eBCG\u003cb\u003e\u0026middot;\u003c/b\u003e\u003csup\u003e+\u003c/sup\u003e + \u003cb\u003e\u0026middot;\u003c/b\u003eOH + \u003cb\u003e\u0026middot;\u003c/b\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026oline; \u0026rarr; Degraded products (7)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.5. Photocatalytic performance of BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e S-scheme heterojunction mechanism.\u003c/h2\u003e\u003cp\u003eThe interfacial charge transport between BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003ewas examined using a computational study based on DFT. The work functions give information about the band alignments and charge transfer direction in the heterojunction. The following equation was used to compute the work functions of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e.[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$$\\:{\\phi\\:}\\:={E}_{vac}-{E}_{F}\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\:\\left(8\\right)$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere E\u003csub\u003eF\u003c/sub\u003e stands for the energy of the Fermi level and E\u003csub\u003evac\u003c/sub\u003e for the energy of the vacuum level.\u003c/p\u003e\u003cp\u003eIn BVG-, the calculated work function of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and BiVO\u003csub\u003e4\u003c/sub\u003e were found to be 4.42 and 5.12 eV and the Fermi level is -4.69 eV and \u0026minus;\u0026thinsp;5.4 eV, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ec and d. Based on the band energy levels of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e possible mechanism for the degradation of BCG is illustrated in Scheme \u003cspan refid=\"Sch1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The VB and CB of BiVO\u003csub\u003e4\u003c/sub\u003e are located at 2.51 eV and 0.19 eV vs. RHE, respectively, and for g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, VB and CB are situated at 2.48 eV and \u0026minus;\u0026thinsp;0.39 eV vs. RHE, respectively. The VB of BiVO\u003csub\u003e4\u003c/sub\u003e is slightly lower than the VB of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. Upon illumination, both the semiconductors were excited and generated electron-hole pairs, and electrons from the CB of BiVO\u003csub\u003e4\u003c/sub\u003e are spontaneously transferred to the VB of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e due to the difference in the energy levels, creating positively charged BiVO\u003csub\u003e4\u003c/sub\u003e and negatively charged g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. An inner electric field at the interface of BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e could be expected to be built. CB of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e was more negative than the redox potentials (O\u003csub\u003e2\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003e\u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e = -0.33 V \u003cem\u003evs\u003c/em\u003e RHE). Hence, g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e can drive O\u003csub\u003e2\u003c/sub\u003e reduction to superoxide radicals (\u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e) and BiVO\u003csub\u003e4\u003c/sub\u003e can drive water anion oxidation to hydroxyl radicals (\u0026middot;OH). Therefore, based on the band edge positions, BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e follows a S-scheme mechanism. In an S-scheme heterojunction, photogenerated electrons from the CB of BiVO\u003csub\u003e4\u003c/sub\u003e recombine with VB holes of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4,\u003c/sub\u003e preserving the strong redox abilities the generation of active species contributes to the improved photocatalysis.\u003c/p\u003e\u003cp\u003eA high BiVO\u003csub\u003e4\u003c/sub\u003e amount causes particle agglomeration, which decreases surface area and active sites. It also prevents light from reaching the more active component, which lowers the utilization of light overall which is further supported by PL technique.. On the other hand, a higher g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e content and a lower BiVO\u003csub\u003e4\u003c/sub\u003e content enhance light absorption, producing more electron-hole pairs and lowering recombination, these results are consistent with the electrochemical study. Improved charge carrier separation and redox potential of the photoexcited electrons and holes are achieved by tuning the band locations to generate an S-scheme heterojunction with a lower quantity of BiVO\u003csub\u003e4\u003c/sub\u003e that benefits from its oxidation capacity.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWhen H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was added to the reaction system, the rate at which BCG degraded significantly increased. H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e and BVG-1 together may accelerate the color removal dye. The surface adsorption of contaminants, however, limits the quantity of BCG dye molecules that are decolorized. The heterostructure trapping/detrapping oxidation states of Bi\u003csup\u003e3+\u003c/sup\u003e and V\u003csup\u003e5+\u003c/sup\u003e affect the generation of \u0026middot;OH, and when \u0026middot;OH intern interacts with H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, \u0026middot;OOH is produced (Eq.\u0026nbsp;6\u0026ndash;8). On the other hand, a combination of BVG-1 with EDTA, IPA and p-BQ decreases photocatalytic degradation due to trapping of h\u003csup\u003e+\u003c/sup\u003e, \u003cb\u003e\u0026middot;\u003c/b\u003eOH, and \u003cb\u003e\u0026middot;\u003c/b\u003eO\u003csub\u003e2\u003c/sub\u003e\u0026oline; (Eq.\u0026nbsp;9\u0026ndash;12). Figure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eb reveals that \u003cb\u003e\u0026middot;\u003c/b\u003eOH radicals played a crucial role in the degradation of BCG.\u003c/p\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e (h\u003csup\u003e+\u003c/sup\u003e)\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e \u0026rarr; \u003cb\u003e\u0026middot;\u003c/b\u003eOH\u0026thinsp;+\u0026thinsp;OH\u0026oline; + BiVO\u003csub\u003e4\u003c/sub\u003e (9)\u003c/p\u003e\u003cp\u003eg-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (e\u003csup\u003e\u0026minus;\u003c/sup\u003e)\u0026thinsp;\u003cb\u003e+\u003c/b\u003e\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e \u0026rarr; \u003cb\u003e\u0026middot;\u003c/b\u003eOH\u0026thinsp;+\u0026thinsp;OH\u0026oline; + g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (10)\u003c/p\u003e\u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e + \u003cb\u003e\u0026middot;\u003c/b\u003eOH \u0026rarr;\u003cb\u003e\u0026middot;\u003c/b\u003eOOH\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO (11)\u003c/p\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003e g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (e\u003csup\u003e\u0026minus;\u003c/sup\u003e + h\u003csup\u003e+\u003c/sup\u003e) + \u003cb\u003e\u0026middot;\u003c/b\u003eOH\u0026thinsp;+\u0026thinsp;IPA \u0026rarr; IPA\u003csup\u003e+\u003c/sup\u003e + OH\u0026oline; + BiVO\u003csub\u003e4\u003c/sub\u003e\u003cb\u003e/\u003c/b\u003e g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (12)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePercentage and rate constant values for the degradation of BCG using 1) BiVO\u003csub\u003e4,\u003c/sub\u003e 2) g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, 3) BVG-1, 4) BVG-2 and 5) BVG-3 catalysts at 90 min.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSl No\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCatalysts\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e% Degradation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRate Constant\u003c/p\u003e\u003cp\u003emin\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003ex10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePhotonic efficiency (10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBiVO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e53.56\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0081\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e7.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eg-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e50.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0068\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e6.38\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBVG-1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e92.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0210\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e10.48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBVG-2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e80.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0159\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e9.72\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBVG-3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e75.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0142\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e9.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBVG-1 with H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e98.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0359\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e11.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn comparison to pure BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, the as-prepared g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/BiVO\u003csub\u003e4\u003c/sub\u003e composites shown higher photocatalytic activity for the degradation of BCG under visible light. The synthesized BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e samples exhibit both tetragonal and monoclinic phases. This study has examined the optimization of the g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e weight ratio as well as BiVO\u003csub\u003e4\u003c/sub\u003e. The g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e peak vanished in the g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/BiVO\u003csub\u003e4\u003c/sub\u003e due to the crystallinity of BiVO\u003csub\u003e4\u003c/sub\u003e. BVG-1 is more beneficial than BVG-3 and BVG-6 because it exhibits a slightly larger band gap, reduced resistance, and lowered photoluminescence intensity. In addition to the extended lifespan of the photo-excited charge carrier compared to pure BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, the BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e sample allows for the efficient separation of more electron\u0026ndash;hole pairs. The S-scheme charge transfer mechanism of g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/BiVO\u003csub\u003e4\u003c/sub\u003e composites, which is generated by the combined effects of BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, results in notable photocatalytic activity.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflict of interest\u003c/h2\u003e\u003cp\u003eAll the Authors declare no conflict of interest\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConceptualization: Pooja Mohan and Prathibha CP; Methodology: Pooja Mohan; Formal analysis and investigation: Dr Srinivas M and Dr Sakthivel K ; Writing - original draft preparation: Prathibha C P, Rajesh B M ; Writing - review and editing: Dr Srinivas M and Dr S Girish Kumar; Supervision: Dr Srinivas M.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors acknowledge the Department of Chemistry, School of Applied Sciences, REVA University, Bengaluru (RU:EST:CH:2022/21) and RVCE NVIDIA GPU facility for DFT calculations.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll the Data has been included in the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAsahi R, Morikawa T, Ohwaki T, et al (2001) Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides. Science 293:269\u0026ndash;271. https://doi.org/10.1126/science.1061051\u003c/li\u003e\n\u003cli\u003eFu X, Kong Y, Wang M, et al (2024) MXene derived Ti\u003csub\u003e3\u003c/sub\u003eC\u003csub\u003e2\u003c/sub\u003e/TiO\u003csub\u003e2\u003c/sub\u003e/Ag persistent photocatalyst with enhanced electron storage capacity for round-the-clock degradation of organic pollutant. Journal of Colloid and Interface Science 656:233\u0026ndash;240. https://doi.org/10.1016/j.jcis.2023.11.079\u003c/li\u003e\n\u003cli\u003eCheng H, Huang B, Lu J, et al (2010) Synergistic effect of crystal and electronic structures on the visible-light-driven photocatalytic performances of Bi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e polymorphs. Phys Chem Chem Phys 12:15468\u0026ndash;15475. https://doi.org/10.1039/C0CP01189D\u003c/li\u003e\n\u003cli\u003eLi F, Kang Y, Chen M, et al (2016) Photocatalytic degradation and removal mechanism of ibuprofen via monoclinic BiVO\u003csub\u003e4\u003c/sub\u003e under simulated solar light. Chemosphere 150:139\u0026ndash;144. https://doi.org/10.1016/j.chemosphere.2016.02.045\u003c/li\u003e\n\u003cli\u003eGerand B, Nowogrocki G, Guenot J, Figlarz M (1979) Structural study of a new hexagonal form of tungsten trioxide. Journal of Solid State Chemistry 29:429\u0026ndash;434. https://doi.org/10.1016/0022-4596(79)90199-3\u003c/li\u003e\n\u003cli\u003eSleight AW, Chen H -y., Ferretti A, Cox DE (1979) Crystal growth and structure of BiVO\u003csub\u003e4\u003c/sub\u003e. Materials Research Bulletin 14:1571\u0026ndash;1581. https://doi.org/10.1016/0025-5408(72)90227-9\u003c/li\u003e\n\u003cli\u003eTokunaga S, Kato H, Kudo A (2001) Selective Preparation of Monoclinic and Tetragonal BiVO\u003csub\u003e4 \u003c/sub\u003ewith Scheelite Structure and Their Photocatalytic Properties. Chem Mater 13:4624\u0026ndash;4628. https://doi.org/10.1021/cm0103390\u003c/li\u003e\n\u003cli\u003eKim TW, Choi K-S (2014) Nanoporous BiVO\u003csub\u003e4 \u003c/sub\u003ePhotoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water Splitting. Science 343:990\u0026ndash;994. https://doi.org/10.1126/science.1246913\u003c/li\u003e\n\u003cli\u003eSaison T, Chemin N, Chan\u0026eacute;ac C, et al (2015) New Insights Into BiVO\u003csub\u003e4 \u003c/sub\u003eProperties as Visible Light Photocatalyst. J Phys Chem C 119:12967\u0026ndash;12977. https://doi.org/10.1021/acs.jpcc.5b01468\u003c/li\u003e\n\u003cli\u003eShi W, Yan Y, Yan X (2013) Microwave-assisted synthesis of nano-scale BiVO\u003csub\u003e4 \u003c/sub\u003ephotocatalysts and their excellent visible-light-driven photocatalytic activity for the degradation of ciprofloxacin. Chemical Engineering Journal 215\u0026ndash;216:740\u0026ndash;746. https://doi.org/10.1016/j.cej.2012.10.071\u003c/li\u003e\n\u003cli\u003eTan G, Zhang L, Ren H, et al (2013) Effects of pH on the Hierarchical Structures and Photocatalytic Performance of BiVO\u003csub\u003e4 \u003c/sub\u003ePowders Prepared via the Microwave Hydrothermal Method. ACS Appl Mater Interfaces 5:5186\u0026ndash;5193. https://doi.org/10.1021/am401019m\u003c/li\u003e\n\u003cli\u003eKhan I, Ali S, Mansha M, Qurashi A (2017) Sonochemical assisted hydrothermal synthesis of pseudo-flower shaped Bismuth vanadate (BiVO\u003csub\u003e4\u003c/sub\u003e) and their solar-driven water splitting application. Ultrasonics Sonochemistry 36:386\u0026ndash;392. https://doi.org/10.1016/j.ultsonch.2016.12.014\u003c/li\u003e\n\u003cli\u003eLiu H, Hou H, Gao F, et al (2016) Tailored Fabrication of Thoroughly Mesoporous BiVO\u003csub\u003e4 \u003c/sub\u003eNanofibers and Their Visible-Light Photocatalytic Activities. ACS Appl Mater Interfaces 8:1929\u0026ndash;1936. https://doi.org/10.1021/acsami.5b10086\u003c/li\u003e\n\u003cli\u003eLv C, Sun J, Chen G, et al (2017) Organic salt induced electrospinning gradient effect: Achievement of BiVO\u003csub\u003e4 \u003c/sub\u003enanotubes with promoted photocatalytic performance. Applied Catalysis B: Environmental 208:14\u0026ndash;21. https://doi.org/10.1016/j.apcatb.2017.02.058\u003c/li\u003e\n\u003cli\u003eLiu C, Su J, Zhou J, Guo L (2016) A Multistep Ion Exchange Approach for Fabrication of Porous BiVO\u003csub\u003e4 \u003c/sub\u003eNanorod Arrays on Transparent Conductive Substrate. ACS Sustainable Chem Eng 4:4492\u0026ndash;4497. https://doi.org/10.1021/acssuschemeng.6b00971\u003c/li\u003e\n\u003cli\u003eGarc\u0026iacute;a-P\u0026eacute;rez UM, Mart\u0026iacute;nez-de la Cruz A, Sep\u0026uacute;lveda-Guzm\u0026aacute;n S, Peral J (2014) Low-temperature synthesis of BiVO\u003csub\u003e4 \u003c/sub\u003epowders by Pluronic-assisted hydrothermal method: Effect of the surfactant and temperature on the morphology and structural control. Ceramics International 40:4631\u0026ndash;4638. https://doi.org/10.1016/j.ceramint.2013.09.002\u003c/li\u003e\n\u003cli\u003eHojamberdiev M, Zhu G, Kadirova ZC, et al (2015) Morphology-controlled growth of BiVO\u003csub\u003e4 \u003c/sub\u003ecrystals by hydrothermal method assisted with ethylene glycol and ethylenediamine and their photocatalytic activity. Materials Chemistry and Physics 165:188\u0026ndash;195. https://doi.org/10.1016/j.matchemphys.2015.09.015\u003c/li\u003e\n\u003cli\u003eHo-Kimura S, Moniz SJA, Handoko AD, Tang J (2014) Enhanced photoelectrochemical water splitting by nanostructured BiVO\u003csub\u003e4\u003c/sub\u003e\u0026ndash;TiO\u003csub\u003e2\u003c/sub\u003e composite electrodes. J Mater Chem A 2:3948\u0026ndash;3953. https://doi.org/10.1039/C3TA15268E\u003c/li\u003e\n\u003cli\u003eZhao K, Zhang Z, Feng Y, et al (2020) Surface oxygen vacancy modified Bi\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e6\u003c/sub\u003e/MIL-88B(Fe) heterostructure with enhanced spatial charge separation at the bulk \u0026amp; interface. Applied Catalysis B: Environmental 268:118740. https://doi.org/10.1016/j.apcatb.2020.118740\u003c/li\u003e\n\u003cli\u003eZhang L, Zhang J, Yu H, Yu J (2022) Emerging S-Scheme Photocatalyst. Advanced Materials 34:2107668. https://doi.org/10.1002/adma.202107668\u003c/li\u003e\n\u003cli\u003eXu F, Meng K, Cheng B, et al (2020) Unique S-scheme heterojunctions in self-assembled TiO\u003csub\u003e2\u003c/sub\u003e/CsPbBr\u003csub\u003e3\u003c/sub\u003e hybrids for CO\u003csub\u003e2\u003c/sub\u003e photoreduction. Nat Commun 11:4613. https://doi.org/10.1038/s41467-020-18350-7\u003c/li\u003e\n\u003cli\u003eGe H, Xu F, Cheng B, et al (2019) S-Scheme Heterojunction TiO\u003csub\u003e2\u003c/sub\u003e/CdS Nanocomposite Nanofiber as H\u003csub\u003e2\u003c/sub\u003e-Production Photocatalyst. ChemCatChem 11:6301\u0026ndash;6309. https://doi.org/10.1002/cctc.201901486\u003c/li\u003e\n\u003cli\u003eYang Y, Cheng B, Yu J, et al (2023) TiO\u003csub\u003e2\u003c/sub\u003e/In\u003csub\u003e2\u003c/sub\u003eS\u003csub\u003e3\u003c/sub\u003e S-scheme photocatalyst with enhanced H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e-production activity. Nano Res 16:4506\u0026ndash;4514. https://doi.org/10.1007/s12274-021-3733-0\u003c/li\u003e\n\u003cli\u003ezhang T, Maihemllti M, Okitsu K, et al (2021) In situ self-assembled S-scheme BiOBr/pCN hybrid with enhanced photocatalytic activity for organic pollutant degradation and CO\u003csub\u003e2\u003c/sub\u003e reduction. Applied Surface Science 556:149828. https://doi.org/10.1016/j.apsusc.2021.149828\u003c/li\u003e\n\u003cli\u003eXia P, Cao S, Zhu B, et al (2020) Designing a 0D/2D S-Scheme Heterojunction over Polymeric Carbon Nitride for Visible-Light Photocatalytic Inactivation of Bacteria. Angewandte Chemie International Edition 59:5218\u0026ndash;5225. https://doi.org/10.1002/anie.201916012\u003c/li\u003e\n\u003cli\u003eZhou L, Li Y, Yang S, et al (2021) Preparation of novel 0D/2D Ag2WO4/WO3 Step-scheme heterojunction with effective interfacial charges transfer for photocatalytic contaminants degradation and mechanism insight. Chemical Engineering Journal 420:130361. https://doi.org/10.1016/j.cej.2021.130361\u003c/li\u003e\n\u003cli\u003eGaneshbabu M, Kannan N, Venkatesh PS, et al (2020) Synthesis and characterization of BiVO\u003csub\u003e4\u003c/sub\u003e nanoparticles for environmental applications. RSC Adv 10:18315\u0026ndash;18322. https://doi.org/10.1039/D0RA01065K\u003c/li\u003e\n\u003cli\u003eKalidasan K, Mallapur S, Kumar SG (2024) Pivotal role of surface and bulk Gd species in WO3 to promote Type-II charge carrier transfer pathways in Gd-WO3/g-C3N4 heterojunction photocatalyst. Journal of Environmental Chemical Engineering 12:113054\u003c/li\u003e\n\u003cli\u003eDabodiya TS, Selvarasu P, Murugan AV (2019) Tetragonal to Monoclinic Crystalline Phases Change of BiVO4 via Microwave-Hydrothermal Reaction: In Correlation with Visible-Light-Driven Photocatalytic Performance. Inorg Chem 58:5096\u0026ndash;5110. https://doi.org/10.1021/acs.inorgchem.9b00193\u003c/li\u003e\n\u003cli\u003eZou Y, Lu M, Jiang Z, et al (2021) Hydrothermal synthesis of Zn-doped BiVO4 with mixed crystal phase for enhanced photocatalytic activity. Optical Materials 119:111398. https://doi.org/10.1016/j.optmat.2021.111398\u003c/li\u003e\n\u003cli\u003eBabu P, Mohanty S, Naik B, Parida K (2019) Serendipitous Assembly of Mixed Phase BiVO4 on B-Doped g-C3N4: An Appropriate p\u0026ndash;n Heterojunction for Photocatalytic O2 evolution and Cr(VI) reduction. Inorg Chem 58:12480\u0026ndash;12491. https://doi.org/10.1021/acs.inorgchem.9b02309\u003c/li\u003e\n\u003cli\u003eDabodiya TS, George T, Vadivel Murugan A (2023) Enhanced Solar-Photo(Electro)catalysis of Microwave-Hydrothermal Synthesized BiVO4, ms-BiVO4/Reduced Graphene Oxide/Ag3PO4 Nanohybrid: Crystalline Phase-Dependent Interfacial Charge Carrier Dynamics. Energy Technology 11:2201099. https://doi.org/10.1002/ente.202201099\u003c/li\u003e\n\u003cli\u003eLi W, Chen Q, Zhong Q (2020) One-pot fabrication of mesoporous g-C3N4/NiS co-catalyst counter electrodes for quantum-dot-sensitized solar cells. J Mater Sci 55:10712\u0026ndash;10724. https://doi.org/10.1007/s10853-020-04672-w\u003c/li\u003e\n\u003cli\u003eZhong K, Feng J, Gao H, et al (2019) Fabrication of BiVO4@g-C3N4(100) heterojunction with enhanced photocatalytic visible-light-driven activity. Journal of Solid State Chemistry 274:142\u0026ndash;151. https://doi.org/10.1016/j.jssc.2019.03.022\u003c/li\u003e\n\u003cli\u003eZhang Z, Wang M, Cui W, Sui H (2017) Synthesis and characterization of a core\u0026ndash;shell BiVO4@g-C3N4 photo-catalyst with enhanced photocatalytic activity under visible light irradiation. RSC Adv 7:8167\u0026ndash;8177. https://doi.org/10.1039/C6RA27766G\u003c/li\u003e\n\u003cli\u003eXie Q, He W, Liu S, et al (2020) Bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalysts toward artificial carbon cycling. Chinese Journal of Catalysis 41:140\u0026ndash;153. https://doi.org/10.1016/S1872-2067(19)63481-9\u003c/li\u003e\n\u003cli\u003eChen F, Zhang X, Tang Y, et al (2020) Facile and rapid synthesis of a novel spindle-like heterojunction BiVO4 showing enhanced visible-light-driven photoactivity. RSC Adv 10:5234\u0026ndash;5240. https://doi.org/10.1039/C9RA07891F\u003c/li\u003e\n\u003cli\u003eLi C, Che H, Liu C, et al (2019) Facile fabrication of g-C3N4 QDs/BiVO4 Z-scheme heterojunction towards enhancing photodegradation activity under visible light. Journal of the Taiwan Institute of Chemical Engineers 95:669\u0026ndash;681. https://doi.org/10.1016/j.jtice.2018.10.011\u003c/li\u003e\n\u003cli\u003eZalfani M, Schueren B van der, Hu Z-Y, et al (2015) Novel 3DOM BiVO4/TiO2 nanocomposites for highly enhanced photocatalytic activity. J Mater Chem A 3:21244\u0026ndash;21256. https://doi.org/10.1039/C5TA00783F\u003c/li\u003e\n\u003cli\u003eLi Y, Qin T, Chen W, et al (2022) Construction of a Switchable g-C3N4/BiVO4 Heterojunction from the Z-Scheme to the Type II by Incorporation of Pyromellitic Diimide. Crystal Growth \u0026amp; Design 22:1645\u0026ndash;1653. https://doi.org/10.1021/acs.cgd.1c01163\u003c/li\u003e\n\u003cli\u003eChen Y, Ma X, Li D, et al (2017) Mechanism of enhancing visible-light photocatalytic activity of BiVO 4 via hybridization of graphene based on a first-principles study. RSC Advances 7:4395\u0026ndash;4401. https://doi.org/10.1039/C6RA25721F\u003c/li\u003e\n\u003cli\u003eWang J, Wang G, Cheng B, et al (2021) Sulfur-doped g-C3N4/TiO2 S-scheme heterojunction photocatalyst for Congo Red photodegradation. Chinese Journal of Catalysis 42:56\u0026ndash;68. https://doi.org/10.1016/S1872-2067(20)63634-8\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Mixed phase, S-scheme heterojunction, electrochemical measurements, Charge carriers, Photocatalysis","lastPublishedDoi":"10.21203/rs.3.rs-7580004/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7580004/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDesign and fabrication of heterojunction comprising the vanadates and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e has drawn significant interests from the prospect of full-scale utilization of solar energy. In this context, the present work attempts the simple annealing step for the heterojunction formation between BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. Strikingly, BiVO\u003csub\u003e4\u003c/sub\u003e adopted pure monoclinic phase, which partially transformed to mixed monoclinic and tetragonal upon combination with g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. Such an intricate ternary phase was confirmed by X-ray diffraction technique and optical response measurements revealed the light absorption capacity in the significant portion of solar light. The electrochemical analysis confirmed the extended lifetime for the photogenerated charge carriers. The photocatalytic activity was investigated for the degradation of bromocresol green and composite performance exceeded compared to their pure phase counterparts. The radical scavenging experiments and alignment of band gap edges substantiated the formation of S-scheme heterojunction between BiVO\u003csub\u003e4\u003c/sub\u003e/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. It was proposed that the bulk recombination of charge carriers in BiVO\u003csub\u003e4\u003c/sub\u003e was greatly hindered due to the formation of homojunctions between the different crystal polymorphs of BiVO\u003csub\u003e4\u003c/sub\u003e. On the other hand, interfacial charge carrier transfer process emerging from the interfacial electric field between BiVO\u003csub\u003e4\u003c/sub\u003e and g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e prompted for the S-scheme charge carrier transfer pathways.\u003c/p\u003e","manuscriptTitle":"Binary composites of (m-t) BiVO 4 /g-C 3 N 4 as an efficient S-scheme photocatalyst for bromocresol green degradation under visible light","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-24 09:23:26","doi":"10.21203/rs.3.rs-7580004/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e3d2f23a-5686-4c01-9682-f57d3a61823e","owner":[],"postedDate":"September 24th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T16:06:59+00:00","versionOfRecord":{"articleIdentity":"rs-7580004","link":"https://doi.org/10.1007/s10854-025-16555-4","journal":{"identity":"journal-of-materials-science-materials-in-electronics","isVorOnly":false,"title":"Journal of Materials Science: Materials in Electronics"},"publishedOn":"2026-01-11 15:59:24","publishedOnDateReadable":"January 11th, 2026"},"versionCreatedAt":"2025-09-24 09:23:26","video":"","vorDoi":"10.1007/s10854-025-16555-4","vorDoiUrl":"https://doi.org/10.1007/s10854-025-16555-4","workflowStages":[]},"version":"v1","identity":"rs-7580004","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7580004","identity":"rs-7580004","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}