Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials

Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials | 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 Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials Yalian Li, Jinxuan Han, Guozhu Li, Honggang Zhao, Yuhua Ma, Qingling Bai, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7239099/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Oct, 2025 Read the published version in Research on Chemical Intermediates → Version 1 posted 10 You are reading this latest preprint version Abstract In photocatalytic degradation of pollutants, hydrogen-related defects on the catalyst surface inhibit the generation of highly reactive hydroxyl radicals (·OH) and superoxide radicals (·O 2 − ). Therefore, strategies to mitigate such defects are crucial for enhancing photocatalytic efficiency. To address this challenge, ZnWO 4 /HRP heterojunction photocatalysts were successfully prepared via a simple hydrothermal method, constructing a compact interfacial structure where rod-shaped ZnWO 4 uniformly attaches to the HRP surface. Photocatalytic performance tests revealed that the composites exhibited excellent catalytic activity for rhodamine B (RhB) degradation, with a rate constant of 0.21 min − 1 within 15 min − 3.5 and 21 times higher than those of individual HRP and ZnWO 4 , respectively. Moreover, due to the robust chemical structure and strong interfacial bonding between ZnWO 4 and HRP, the composite maintains high photocatalytic stability across multiple catalytic cycles. Mechanistic analysis demonstrates that the S-scheme heterojunction effectively suppresses the formation of hydrogen-related defects on the ZnWO 4 surface, significantly reducing surface defect state density. This inhibition enhances photogenerated carrier separation, accelerates charge transfer, and facilitates the efficient generation of ·O 2 − . By adopting a heterojunction strategy to address hydrogen - related defects, the catalyst’s visible-light absorption capacity, photoelectric conversion efficiency, and radical generation efficiency were enhanced, while carrier recombination was suppressed. These findings provide new insights for designing high-efficiency heterojunction photocatalysts and highlight their promising potential in photocatalytic removal of organic pollutants. Photocatalysis S-scheme heterojunction Hydrogen-related defect Pollutant degradation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Water pollution control remains a critical research focus worldwide [ 1 , 2 ]. Photocatalytic technology holds significant potential for organic pollutant removal due to its low energy consumption and mild reaction conditions [ 3 ]. The development and synthesis of efficient semiconductor materials are pivotal for the practical implementation of photocatalytic technology [ 4 , 5 ]. However, single-component semiconductors have many limitations in practical applications. The core problem lies in the low separation efficiency of photo-generated electrons and holes, which causes carriers to recombine rapidly[ 6 ]. These limitations hinder their widespread use. To improve the separation efficiency of charge carriers in single-layer semiconductor materials, researchers have developed a variety of control strategies, including the control of semiconductor size and morphology, ion doping, and the construction of heterostructures [ 7 , 8 ]. Among these, composite heterojunctions formed by integrating two complementary semiconductor materials can significantly enhance light absorption and facilitate photogenerated carrier separation/migration, thereby improving photocatalytic performance [ 9 ].In recent years, S-scheme heterojunctions-constructed by combining reduced-state photoactive materials with high conduction band positions and oxidized-state photocatalysts with low valence band positions-have garnered significant scientific attention [ 10 ]. Compared to other heterojunction types, S-scheme heterojunctions offer distinct advantages: they enable efficient electron-hole separation while preserving and enhancing the redox capacity of photocatalytic materials, making them highly effective for improving photocatalytic performance [ 11 , 12 ].Thus, identifying two semiconductor photocatalysts with matched energy band structures and constructing S-scheme heterojunctions between them is essential for optimizing the photocatalytic performance of single-component semiconductors[ 13 , 14 ]. ZnWO 4 has found extensive application in photocatalytic fields owing to its outstanding chemical stability and exceptional optical as well as electrochemical properties. [ 15 ]. However, surface hydroxyl groups formed in the synthesis process of ZnWO 4 may trigger hydrogen-related defects, which serve as locations for carrier trapping and recombination. This decreases the number of accessible carriers on the catalyst surface, consequently suppressing the formation of highly reactive superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH)[ 16 ]. During photocatalysis, free radical production facilitates the decomposition of pollutants into CO 2 , water, and inorganic acids [ 17 ]. Therefore, suppressing hydrogen-related defects in ZnWO 4 is critical to enhancing its photocatalytic performance. Strategies to address this issue primarily involve constructing semiconductor heterojunctions, such as Type II (BiOBr/ZnWO 4 [ 18 ]), Type Z (Ag 2 MoO 4 /ZnWO 4 [ 19 ], ZnWO 4 /TiO 2 /MoS 2 [ 20 ]), which exhibit higher photocatalytic efficiencies than pure ZnWO 4 . However, reports on constructing S-scheme heterojunctions between ZnWO 4 and other semiconductors remain limited, making it essential to identify suitable partners for S-scheme heterostructure formation. Red phosphorus (RP), a common photoactive material, possesses a tunable bandgap (1.7–2.4 eV) and exhibits strong absorption of visible light with wavelengths up to 700 nm[ 21 ]. However, rapid photogenerated carrier recombination significantly limits its photocatalytic performance [ 22 ]. Given the matched energy band structures of ZnWO 4 and hydrothermal red phosphorus (HRP), constructing stable heterojunctions is expected to mitigate their individual drawbacks and enhance overall photocatalytic performance. In this study, ZnWO 4 /HRP S-scheme heterojunctions were prepared by combining HRP with ZnWO 4 via a green and simple hydrothermal method. Such an approach efficiently lessens hydrogen-related defects on ZnWO 4 surfaces while enhancing electron-hole pair separation efficiency, thus attaining optimal photocatalytic performance. Lastly, the photocatalytic mechanism for the ZnWO 4 /HRP composite was examined and deliberated. Experimental section Materials The chemical reagents involved in this study are commercially available and can be used directly without additional treatment. Among these, zinc nitrate and sodium tungstate dihydrate were obtained from Chengdu Kelong Chemical Reagent Factory. Ammonium oxalate, tert-butanol, and isopropanol (C 3 H 8 O) were provided by Tianjin Yongsheng Fine Chemicals Factory. Rhodamine B was obtained from Tianjin Tianxin Fine Chemical Development Center. Benzoquinone was supplied by Shanghai Third Reagent Factory. Anhydrous ethanol and acetone were likewise obtained from Tianjin Guangfu Technology Development Co. RP was acquired from Zhejiang Yongjia Fine Chemical Factory. Synthesis of ZnWO 4 /HRP composites photocatalysts Synthesis of ZnWO 4 : 5 mmol of Na 2 WO 4 ·2H 2 O and Zn(NO 3 ) 2 were dissolved in water, with the mixture being ultrasonically stirred for 30 min. And the solution was placed under hydrothermal reaction at 180°C for 24 h. Following the hydrothermal treatment, the obtained product was subjected to three rounds of washing, subsequently dried at 60°C, and was ultimately designated as ZnWO 4 . Synthesis of ZnWO 4 /HRP composites: HRP was treated according to reference [ 23 ]. A specific quantity of ZnWO 4 and HRP were milled for 30 min, after which hydrothermal treatment was carried out at 150°C. After hydrothermal treatment, the ZnWO 4 /HRP composites were dried at 60°C. Characterization of photocatalysts In this study, multiple characterization techniques were employed to conduct a comprehensive analysis of the various properties of the samples. The microscopic morphology of the samples was examined with a Zeiss SIGMA 300 scanning electron microscope (SEM). The crystalline structural characteristics of the samples were ascertained using a Bruker D8 Advance X-ray diffractometer (XRD). The molecular structure and functional groups of the samples were characterized using a TENSOR27 model Fourier transform infrared spectrometer (FT-IR). X-ray photoelectron spectroscopy (XPS) measurements were conducted using a Thermo Fisher ESCALAB 250Xi X-ray photoelectron spectrometer equipped with a monochromatic Al Kα excitation source. The specific surface area and pore size distribution of the samples were determined with a Micromeritics ASAP 2460 physisorption analyzer. Data for ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) were collected by a Shimadzu UV-3600i Plus spectrophotometer. Electrochemical tests were carried out on a CHI660C electrochemical workstation, utilizing a three-electrode system that included an indium tin oxide (ITO) working electrode, a platinum wire counter electrode, and a saturated Ag/AgCl reference electrode. Photoelectrochemical detection The photocurrent response characteristics (I-T) and electrochemical impedance spectroscopy (EIS) of the samples were tested and characterized using a CHI660E electrochemical workstation. The experiments were conducted under 300 W xenon light illumination with a standard three-electrode system: the target photocatalyst-modified electrode functioned as the working electrode, a platinum wire electrode served as the auxiliary electrode, and an Ag/AgCl electrode immersed in a saturated KCl solution acted as the reference electrode. The electrolyte employed was a 0.5 mol/L sodium sulphate aqueous solution. The specific preparation process for the working electrode was as follows: 5 mg of ZnWO 4 /HRP composite catalyst was taken and mixed with Nafion and ethanol solution at a volume ratio of 1:19; 40 µL of the mixed dispersion was transferred, sonicated until the system became uniform, and then uniformly coated onto the surface of a 1.0 cm 2 indium tin oxide (ITO) conductive glass substrate; the prepared electrode was placed in a 60°C environment and dried for 2 h to ensure that the catalyst particles were firmly loaded onto the ITO substrate surface. Photocatalytic experiment A 300-watt xenon lamp (equipped with a UV filter, with a light intensity of 140 mW/cm 2 ) was employed as the light source for the photocatalytic reaction, and a 10 mg/L Rhodamine B (RhB) solution served as the target pollutant for degradation. The specific experimental procedure was as follows: 5.0 mg of ZnWO 4 /HRP composite material was mixed with 20 mL of RhB solution. Following ultrasonic treatment to achieve uniform dispersion of the system, the mixture was placed in a dark environment and magnetically stirred for 30 min to ensure adequate dispersion of the catalyst and attain adsorption-desorption equilibrium at the solid-liquid interface. Throughout the reaction, samples were collected at regular time intervals. The reaction solution was centrifuged, and the absorbance of the resulting supernatant was determined at 554 nm using a UV-visible spectrophotometer. Results and discussion Characterization of photoelectroactive materials The ZnWO 4 /HRP composite was successfully synthesized through a straightforward hydrothermal approach (Fig. 1 a). We used scanning electron microscopy (SEM) to study the microstructure of photocatalysts. HRP displayed relatively large particle dimensions, a rough surface, and irregular shapes, with particles arranged closely together visible under high magnification (Fig. 1 b, e). Pristine ZnWO 4 formed obvious agglomerates with smooth surfaces and consisted of irregularly stacked nanorods as observed at 10x magnification (Fig. 1 c, f). By comparison, the ZnWO 4 /HRP composite consists of numerous small particles with excellent dispersibility that adhere evenly to the HRP surface, thus creating a more prominent and ordered porous structure (Fig. 1 d, g). This structure promoted the efficient separation and migration of photo-generated charge carriers on the catalyst surface, thereby significantly enhancing the photocatalytic performance of semiconductor materials[ 24 , 25 ]。 The crystal structure and phase purity of the photocatalyst were analyzed using powder X-ray diffraction (XRD) patterns (Fig. 2 a). A distinct diffraction peak at 2θ = 15.3° was observed in pure HRP, corresponding to the (102) crystal plane of amorphous RP. This result matched the characteristic diffraction peak documented in the literature (JCPDS No. 44–0904) [ 26 ]. The XRD spectra of ZnWO 4 were highly consistent with the JCPDS standard card (JCPDS No. 73–0554) [ 27 ]. The diffraction patterns of the ZnWO 4 /HRP composite samples retained the complete diffraction features of ZnWO 4 and clearly displayed the characteristic peaks of HRP’s (102) crystalline facet, confirming the successful preparation of the composites. Notably, the characteristic peak at 2θ = 15° for the composite catalyst appeared sharper than that of pure HRP. This suggested that the combination of ZnWO 4 and HRP led to improved crystallinity of the material, along with enhanced ordering in atomic arrangement. We used Fourier transform infrared spectroscopy (FT-IR) to study the functional group structure of photocatalysts (Fig. 2 b). The absorption peaks at 1008, 1160, and 1634 cm − 1 were attributed to the stretching vibrations of P-P-O, P = O, and P-O, respectively [ 28 ]. The characteristic absorption peaks at 584 and 831 cm − 1 could be attributed to the W-O vibration band in the WO₆ octahedron, while the peak at 716 cm − 1 belonged to the Zn-O-W vibration band [ 29 ]. Notably, within the ZnWO 4 /HRP composite, the bond strength of W-O and Zn-O-W dropped markedly, a phenomenon that could have been linked to chemical bond changes induced by interfacial interactions. The hydroxyl groups on the sample surface formed during hydrothermal synthesis correspond to the 1634 cm − 1 absorption peak, and such hydroxyl groups might induce the formation of hydrogen-related defects [ 30 ]. The absorption peak at 1383 cm − 1 was directly related to hydrogen-related defects on the surface of ZnWO 4 [ 31 ]. These defects were prone to becoming photogenerated carrier recombination centers, thereby reducing photocatalytic efficiency [ 32 ]. Compared with pure ZnWO 4 , the composite exhibits significantly lower peak intensity at 1383 cm − 1 , indicating a reduction in hydrogen-related defects. It was speculated that HRP and ZnWO 4 effectively eliminate surface defects through chemical bonding. Reducing the exposure to hydrogen-related defects could suppress carrier recombination, improve charge transfer efficiency, and promote the separation of photo-generated electron-hole pairs [ 33 ]. X-ray photoelectron spectroscopy (XPS) was used to study the elemental composition and valence state changes of the catalyst. The complete XPS spectrum showed that elements such as P, Zn, W, C, and O were present in the ZnWO 4 /HRP composite material (Fig. 3 a). Of these, P was linked to HRP, whereas Zn and W were linked to ZnWO 4 . This verified the correct elemental proportion of HRP to ZnWO 4 , with no other impurities detected. A more thorough examination of the chemical valence states of elements was performed via XPS fine spectroscopy: within the ZnWO 4 /HRP composite, the 2p 3/2 and 2p 1/2 binding peaks of P were situated at 129.4 eV and 130.2 eV, in that order, corresponding to elemental P (P 0 ) (Fig. 3 b) [ 34 ]. The binding energy peaks of Zn 2p 3/2 and 2p 1/2 were observed at 1022.7 and 1045.9 eV, respectively, indicating that zinc was in the + 2 valence state (Fig. 3 c) [ 35 ]. Furthermore, the W 4f 7/2 and W 4f 5/2 binding peaks were positioned at 36.3 and 38.5 eV, respectively, demonstrating that W existed in the + 6 oxidation state (Fig. 3 d) [ 36 ]. Notably, the P 2p binding energy peak in ZnWO 4 /HRP was lower than that in HRP, which suggested that electron cloud density of the P element had risen. In contrast, Zn 2p and W 4f in the composite shift toward higher binding energies compared to pure ZnWO 4 , showing an opposite trend to that of HRP. These changes revealed electron transfer from ZnWO 4 to HRP, with this transfer arising from the strong interfacial chemical interaction between them. These interactions promoted charge transfer at the interface, significantly improving the separation and transfer efficiency of photo-generated electron-hole pairs, thereby enhancing the photoelectrochemical performance of the composite material [ 37 ]. The combined findings from characterization derived from SEM, XRD, FT-IR, and XPS verified the successful synthesis of ZnWO 4 /HRP heterojunction materials. The specific surface area and pore size characteristics of the photocatalyst were characterized using nitrogen adsorption-desorption isotherms and pore size distribution analysis. The N 2 adsorption-desorption isotherms of HRP, ZnWO 4 , and ZnWO 4 /HRP composite materials all exhibited Type IV isotherm characteristics, indicating that all three materials possessed mesoporous structures (Fig. 4 a). The specific surface area of ZnWO 4 /HRP (29.855 m 2 /g) exceeded that of HRP (2.037 m 2 /g) and ZnWO 4 (27.578 m 2 /g). Additionally, the pore size distribution curves indicated that the pore volumes of HRP, ZnWO 4 , and ZnWO 4 /HRP were 0.016, 0.103, and 0.109 cm 3 /g, respectively (Fig. 4 b). A greater specific surface area not only aided in generating photogenerated carriers during the photocatalytic process but also enabled them to take part in photocatalytic reactions more effectively, thereby enhancing the photocatalytic performance of the composite materials[ 38 ]. The light absorption characteristics of the photocatalysts were studied using ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) (Fig. 5 a). Pure ZnWO 4 showed an absorption edge near 400 nm, which indicated that its absorption was mainly focused in the ultraviolet range, while its absorption in the visible region (λ ≥ 400 nm) was nearly negligible. Compared with ZnWO 4 , the absorption edges of ZnWO 4 /HRP samples underwent an obvious red shift, suggesting that the composite material absorbs more visible light, generating additional electrons and holes. After compositing ZnWO 4 with HRP, ZnWO 4 /HRP demonstrates strong visible light absorption, with its absorption edge generally between those of HRP (around 690 nm) and ZnWO 4 . This demonstrated that the heterostructure formed between HRP and ZnWO 4 further expanded the light absorption range of the composite, thus enhancing its light utilization efficiency and actively facilitating the photocatalytic reaction. Generally speaking, the band gap (E g ) of semiconductor materials could be calculated using the Tauc equation: (αhv) 1/n = A (hv - E g ) (1) h is Planck's constant, α is the absorption coefficient, E g is the bandgap energy, ν is the frequency of light, A is a constant, and n depends on the type of electron transition in the semiconductor: n = 1/2 for direct bandgap semiconductors and n = 2 for indirect bandgap semiconductors. Therefore, the calculated E g values for HRP and ZnWO 4 were 1.8 and 3.1 eV, respectively. The band structure of ZnWO 4 /HRP was further characterized using the Mott-Schottky measurement method (Fig. 5 b). The flat band potentials (E FB ) of HRP and ZnWO 4 were obtained from the intersection of the tangent line with the x-axis, being − 1.08 and − 0.85 V ( vs. Ag/AgCl), respectively. These potentials were then converted to standard hydrogen electrode (NHE) potentials using the following formula (2).: E FB (vs. NHE) = E FB (pH = 0, vs. Ag/AgCl) + E AgCl + 0.059 × pH (2) Here, E AgCl equals 0.197 V and the electrolyte pH is 7. The EFB values for HRP and ZnWO 4 ( vs. NHE) were calculated to be -0.47 and − 0.22 V, respectively. The positive slope of the HRP and ZnWO 4 curves indicated that both were n-type semiconductors. For n-type semiconductors, the conduction band potential (E CB ) was approximately 0.1 V higher than the flat band potential ( vs. NHE) [ 39 ]. Thus, the E CB values of HRP and ZnWO 4 stood at -0.57 and − 0.32 V ( vs. NHE) [ 40 ]. Using the formula E g = E VB - E CB , the valence band potentials (E VB ) of HRP and ZnWO 4 were calculated to be 1.23 and 2.78 V ( vs. NHE), respectively. Electrochemical impedance spectroscopy (EIS), as a precise technique for studying electrode process kinetics and surface phenomena, holds significance in electrochemical testing (Fig. 6 a). To deeply analyze the electrochemical behavior of the photoactive materials, EIS tests were conducted on HRP and ZnWO 4 /HRP composites. All samples displayed circular patterns, yet the EIS arc radius of ZnWO 4 /HRP was notably smaller than that of pure HRP samples. Generally speaking, in electrochemical impedance spectroscopy (EIS), the smaller the arc radius, the lower the electrode impedance and the higher the internal charge transfer efficiency [ 41 ]. The low impedance of ZnWO 4 /HRP provides strong evidence for enhanced conductivity within the heterostructures. In summary, the HRP/ZnWO 4 composite promoted the rapid transfer and effective separation of photogenerated carriers, thereby enhancing its photocatalytic activity. Transient photocurrent (I-T) measurements were utilized to determine the photoelectrochemical characteristics of these catalysts (Fig. 6 b), which visualizes the photogenerated carrier transport properties and separation efficiency. All materials showed a stable transient photocurrent response under light/dark conditions [ 42 ]: When the light source was turned on, the photocurrent increased rapidly; when the light source was blocked, the photocurrent decreased rapidly. Under the same conditions, the photocurrent of ZnWO 4 /HRP reached 0.16 µA/cm 2 , twice that of pure ZnWO 4 (0.08 µA/cm 2 ) and 1.3 times that of pure HRP (0.12 µA/cm 2 ), indicating its superior photo-responsive ability and higher generation of photogenerated carriers, which provided sufficient charge carriers to enhance the reaction efficiency. Moreover, the patterns of current variation exhibited by HRP, ZnWO 4 , and ZnWO 4 /HRP were uniform, a finding that verified the stability of these materials. In conclusion, the HRP/ ZnWO 4 heterojunction significantly enhanced electron-hole separation ability, making its photocatalytic activity superior to that of single materials. Photocatalytic degradation of RhB Using Rhodamine B (RhB) as a pollutant, the photocatalytic performance of the synthesized ZnWO₄/HRP photocatalyst was evaluated (Fig. 7 a). First, HRP, ZnWO 4 , and ZnWO 4 /HRP were stirred in the dark for 30 min to achieve adsorption-desorption equilibrium. Subsequently, visible light irradiation was applied, and it was observed that the concentration of RhB slowly decreased with increasing reaction time. Notably, ZnWO 4 exhibited only 6.6% RhB degradation after 15 min of light irradiation, as its wide bandgap significantly reduced visible light utilization and consequently affected photodegradation ability. HRP achieved 62.5% RhB degradation within 15 min due to its effective visible light response. In contrast, the ZnWO 4 /HRP heterojunction composite catalyst exhibited excellent degradation performance, with a degradation rate of 95.5% for RhB after 15 min of illumination. In addition, dynamic studies of the photodegradation process indicated that the degradation of RhB followed a pseudo-first-order kinetic model (Fig. 7 b). The reaction rate (κ) of the ZnWO 4 /HRP heterojunction was 0.21 min − 1 , which was 3.5 times higher than that of HRP (0.06 min − 1 ) and 21 times higher than that of ZnWO 4 (0.01 min − 1 ). This result indicated that the synergistic effects within the ZnWO 4 /HRP heterojunction not only enhanced ZnWO 4 's response to visible light but also promoted the separation and transfer of photo-generated carriers while effectively suppressing carrier recombination. Catalyst stability was a key indicator for evaluating the performance of photoelectrically active materials[ 43 ]. The photocatalytic stability was tested via multiple rounds of cyclic degradation tests using a 10 mg/L RhB solution (Fig. 7 c). The photodegradation efficiency of ZnWO 4 /HRP toward RhB slightly decreased from 95.4–89.7% within 15 min after five cycling tests. Degradation efficiency's slight decline could have resulted from the loss of photoactive materials in cyclic tests. This research demonstrated that ZnWO 4 /HRP could function as a stable and highly effective photoactive material for repeatedly degrading pollutants. Further experiments were conducted to capture the active substances involved in the photocatalytic reaction of ZnWO 4 /HRP samples (Fig. 7 d). Ammonium oxalate (AO), isopropyl alcohol (IPA), and p-benzoquinone (PBQ) were used as scavengers to capture holes, ·OH, and ·O 2 − , respectively. Under simulated sunlight irradiation, ZnWO 4 /HRP composites achieved 95.5% RhB photodegradation within 15 min. When PBQ was added, RhB photodegradation by ZnWO 4 /HRP decreased from 95.4–57.8%; in contrast, adding the hole scavenger AO caused the degradation rate to drop directly to 46.1%. After adding IPA, the photodegradation rate did not decrease significantly, indicating that ·OH was not the main active substance in the photodegradation process of RhB. All results suggest that holes play the most critical role in the RhB photodegradation reaction, while·O 2 − also serves as a relatively important intermediate active species. Investigation of the mechanism Based on the above discussion, a potential mechanism for the photocatalytic degradation of RhB by ZnWO 4 /HRP heterojunction photocatalysts was proposed (Fig. 8 a and b). If ZnWO 4 formed a Type II heterojunction with HRP, electrons would migrate from the CB of HRP to ZnWO 4 , while holes would migrate from the VB of ZnWO 4 to HRP. However, according to the M-S curve and the Kubelka-Munk equation, the valence band potential of HRP (1.23 V) was lower than the redox potential of ·OH/OH⁻ (1.99 V), making it unable to oxidize OH⁻ to ·OH; additionally, the conduction band potential of ZnWO 4 was higher than the redox potential of O 2 /·O 2 − , so it could not produce more ·O 2 − than HRP. These results contradicted the pre-assumed Type II heterojunction mechanism and instead aligned with a new S-scheme heterojunction. Therefore, a mechanism for the photocatalytic degradation of RhB via a ZnWO 4 /HRP S-scheme heterojunction had been proposed (Fig. 8 c). Under visible light irradiation, photogenerated electrons and holes were produced in HRP and ZnWO 4 . Electrons within ZnWO 4 's CB would move to the VB of HRP, whereas holes in ZnWO 4 's VB and electrons in HRP's CB would gather at the interface. These accumulated electrons would reduce oxygen to ·O 2 − , and certain holes would oxidize water to ·OH. The excellent rhodamine B degradation efficiency exhibited by the ZnWO 4 /HRP composite photocatalyst was closely related to the S-scheme heterojunction it formed. This mechanism enhanced the spatial separation and migration ability of photo-generated electron-hole pairs, broadened the light absorption range, and promoted the generation of more active substances on the catalyst surface, thereby accelerating the degradation of pollutants. Overall, these findings verified that the ZnWO 4 /HRP composite functioned as a highly effective and stable photocatalyst for water remediation. Conclusions In this study, the preparation of ZnWO 4 /HRP heterojunction photocatalysts was achieved by means of a simple hydrothermal approach. The rod-shaped ZnWO 4 was evenly adhered to the HRP surface, thereby forming a tightly-bonded interface. Moreover, it demonstrated remarkable efficacy in the photocatalytic removal of contaminants. The rate of photodegradation of RhB could reach 0.21 min − 1 in just 15 min. This rate was approximately 3.5 times that of HRP (0.06 min − 1 ) and 21 times that of ZnWO 4 (0.01 min − 1 ). The enhancement in photocatalytic efficiency could be attributed to the formation of S-scheme heterojunctions. This heterojunction inhibited the hydrogen-related defects on the ZnWO 4 surface. The suppression of hydrogen-related defects reduced the surface defect state, which effectively inhibited the surface carrier recombination and accelerated the charge transfer. By resolving the issue of hydrogen-related defects and improving carrier separation, the composite achieves outstanding photocatalytic efficiency and stability. The visible light absorption range, photoelectric conversion efficiency, and photocatalytic activity of ZnWO 4 /HRP composites were significantly enhanced. The synthesized ZnWO 4 /HRP composite serves as a highly efficient visible-light catalyst, presenting extensive application prospects. Declarations Acknowledgments This work was financially supported by Xinjiang Uygur Autonomous Region Division and Municipal Financial Science and Technology Program Projects (2024GX07), Key Research and Development Plan Project of Karamay District (2025kqzdyf0024), Autonomous Region Market Supervision and Management Science and Technology (2024152521), “Tianshan Talent” - Youth Top notch Talent Project (2024TSYCCX0067), Natural Science Foundation of Xinjiang Uygur Autonomous Region (2024D01B59, 2024D01A104), “Tianchi Talent” Introduction Program for Young Doctors funded by the Talent Development Fund of Xinjiang Uygur Autonomous Region, The Second Batch of “Tianchi Talent” Young Doctor Introduction Program of Xinjiang Uygur Autonomous Region (601002000102), Scientific Research Project of Basic Scientific Research Funds for Universities in Xinjiang Uygur Autonomous Region (XJEDU2025P070), Xinjiang Normal University 2022 Young Top Talent Project (XJNUQB2022-25), Doctoral Scientific Research Start-up Fund of Xinjiang Normal University (XJNUBS2305) and College Students’ Innovative Entrepreneurial Training (S202410762010, S202410762012, X202410762117). Author contribution Yalian Li: Data curation, Writing - original draft, Conceptualization. Jinxuan Han： Project administration. Guozhu Li: Data curation. Honggang Zhao: Writing - review & editing. Yuhua Ma: Funding acquisition. Qingling Bai: Conceptualization. Zhicheng Wang: Software. Data availability Data will be made available on request. Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References J. Li, D. Wang, S. Zhao, R. Ma, J. Guo, Z. Li, D. Wang, Y. Xuan and L. Wang, Appl. Catal. B. 351 , 124007 (2024). F. Bi, Z. Zheng, R. Li, R. Du, L. Zhao, S. Xiao, L. Wang and X. Dong, Chem. Eng. J. 507 , 160781 (2025). X. Duan, H. Jia and T. Cao, Appl. Catal. B. 352 , 124016 (2024). Q. Su, J. Li and B. Wang, Appl. Catal. B. 318 , 121820 (2022). Y. Zhao, Y. Zhang, L. Wang, C. Ai and J. Zhang, J. Mater. Sci. Technol. 229 , 213 (2025). Y. Ai, J. Hu, X. Xiong, S. A. C. Carabineiro, Y. Li, N. Sirotkin, A. Agafonov and K. Lv, Appl. Catal. B. 353 , 124098 (2024). X. Zou, B. Sun and L. Wang, Chem. Eng. J. 482 , 148818 (2024). C. Pinming, Q. Yang, N. Kayunkid, V. Yordsri, W. Wongwiriyapan and Y. J. Song, J. Mater. Chem. A 13 (14), 9811 (2025). A. H. Navidpour, J. Safaei and M. A. H. Johir, Adv. Compos. Hybrid Mater. 7 (2), 53 (2024). R. Wu, S. Gao, C. Jones, M. Sun, M. Guo, R. Tai, S. Chen and Q. Wang, Adv. Funct. Mater. 34 (24), 2314051 (2024). Y. Ma, X. Aihemaiti, K. Qi, S. Wang, Y. Shi, Z. Wang, M. Gao, F. Gai and Y. Qiu, J. Mater. Sci. Technol. 156 , 217 (2023). Z. Liu, H. Luo, M. Zhang, Y. Mu, F. Bai, M. Zhang and T. Lu, Chem. Eng. J. 491 , 151913 (2024). N. Li, Y. Niu, W. An, F. Ruan, H. Wu, B. Hui, Y. Wang and G. Fan, Appl. Catal. B. 369 , (2025). C. You, X. Zhang, Y. Zhao, R. Yan, Y. Shen, Q. Xue, W. Li, T. Liu, J. Jiang, X. Chen and S. Li, J. Mater. Sci. Technol. 242 , 64 (2025). X. Wang, S. Yu, Z.-H. Li, L.-L. He, Q.-L. Liu, M.-Y. Hu, L. Xu, X.-F. Wang and Z. Xiang, Chem. Eng. J. 405 , 126922 (2021). R. Shi, Y. Wang, D. Li, J. Xu and Y. Zhu, Appl. Catal. B. 100 (1-2), 173 (2010). R. Peter, K. Salamon, A. Omerzu, J. Grenzer, I. J. Badovinac, I. Saric and M. Petravic, J. Phys. Chem. C. 124 (16), 8861 (2020). A. O. C. Andrade, L. H. d. S. Lacerda, M. M. Lage Júnior, S. K. Sharma, M. E. H. Maia da Costa, O. C. Alves, E. C. S. Santos, C. C. dos Santos, A. S. de Menezes, M. A. San-Miguel, F. M. Filho, E. Longo and M. A. P. Almeida, Opt. Mater. 138 , 113701 (2023). J. Zhang, J. Ma, X. Sun, Z. Yi, T. Xian, X. Wu, G. Liu, X. Wang and H. Yang, Langmuir 39 (3), 1159 (2023). H. Zhang, X. Liu, Z. Li, F. Wang, J. Zhang, F. Gao, P. Zhang and Z. Wei, J. Mater. Sci. Technol. 59 (1), 38 (2023). F. Liu, R. Shi, Z. Wang, Y. Weng, C. M. Che and Y. Chen, Angew. Chem., Int. Ed. 58 (34), 11791 (2019). Y. Wang, J. Wu and Y. Yan, Chem. Eng. J. 403 , 126313 (2021). X. Aihemaiti, X. Wang, Y. Li, Y. Wang, L. Xiao, Y. Ma, K. Qi, Y. Zhang, J. Liu and J. Li, Chemosphere. 296 , 134013 (2022). M. Selvamani, A. Alsulmi, A. Sundaramoorthy, S. Vadivel and A. V. Kesavan, J Mater Sci-Mater El. 34 (31), 2094 (2023). X. Shi, Q. Chen, X. Qin, X. Rao, S. Li, G. Liu, J. Wang, X. Dong, D. Luo and F. Chen, Energy Environ. Mater. 8 (4), 70006 (2025). X. Ren, D. Philo, Y. Li, L. Shi, K. Chang and J. Ye, Coord. Chem. Rev. 424 , 213516 (2020). L. Zhen, Z. Yulian, L. Wen, C. Chunxu and Z. Jinfeng, Mater. Sci. Semicond. Process. 160 , 107445 (2023). G. Jia, M. Sun, Y. Wang, X. Cui, B. Huang and J. C. Yu, Adv. Funct. Mater. 33 (10), 2212051 (2022). B. Barik, M. Mishra and P. Dash, Environ. Sci.:Nano. 8 (9), 2676 (2021). Y. Cui, L. Pan, Y. Chen, N. Afzal, S. Ullah, D. Liu, L. Wang, X. Zhang and J.-J. Zou, RSC Adv. 9 (10), 5492 (2019). F. Chen, S. Sun, K. Mu, Y. Li, Z. Shen and S. Zhan, Appl. Catal. B. 312 , 121373 (2022). Z. Li, T. Yu, Z. Zou and J. Ye, Appl. Phys. Lett. 88 (7), 071917 (2006). S. Zhan, F. Zhou, N. Huang, Q. He and Y. Zhu, Chem. Eng. J. 330 , 635 (2017). J. Liu, Y. Zhu, J. Chen, D. S. Butenko, J. Ren, X. Yang, P. Lu, P. Meng, Y. Xu, D. Yang and S. Zhang, J. Hazard. Mater. 413 , 125462 (2021). D. Sun, Q. Wang, W. Wang, Y. Chen and S. Ruan, ACS Appl. Nano Mater. 6 (12), 10581 (2023). M. R. Tamtam, R. Koutavarapu and J. Shim, Environ. Res. 227 , 115735 (2023). M. Dai, Z. He, P. Zhang, X. Li and S. Wang, J. Mater. Sci. Technol. 122 , 231 (2022). H. Zhuang, W. Xu, L. Lin, M. Huang, M. Xu, S. Chen and Z. Cai, J. Mater. Sci. Technol. 35 (10), 2312 (2019). P. Li, J. Guo, X. Ji, Y. Xiong, Q. Lai, S. Yao, Y. Zhu, Y. Zhang and P. Xiao, "Construction of direct Z-scheme photocatalyst by the interfacial interaction of WO 3 and SiC to enhance the redox activity of electrons and holes Chemosphere 282 , 130866 (2021). W. Chen, L. Chang, S. B. Ren, Z. C. He, G. B. Huang and X. H. Liu, "Direct Z-scheme 1D/2D WO 2.72 /ZnIn 2 S 4 hybrid photocatalysts with highly-efficient visible-light-driven photodegradation towards tetracycline hydrochloride removal J. Hazard. Mater. 384 , 121308 (2020). G. Aimaiti, Y. Zou, Y. Ma, Y. Shi, K. Qi, W. Zhan, Z. Qian, Z. Liu and Y. Dong, Chem. Eng. J. 496 , 153852 (2024). Y. Zhao, H. Cui, Y. Hu, S. Li, F. Liu, B. Shen, K. Ge, B. Liu and Y. Yang, Appl. Catal. B. 361 , 124567 (2025). Z. Xu, Q. Duan and X. Cui, Chem. Eng. J. 511 , (2025). Additional Declarations No competing interests reported. Supplementary Files Graphicalabstract.png Cite Share Download PDF Status: Published Journal Publication published 29 Oct, 2025 Read the published version in Research on Chemical Intermediates → Version 1 posted Editorial decision: Revision requested 27 Aug, 2025 Reviews received at journal 27 Aug, 2025 Reviews received at journal 24 Aug, 2025 Reviewers agreed at journal 18 Aug, 2025 Reviewers agreed at journal 18 Aug, 2025 Reviewers agreed at journal 16 Aug, 2025 Reviewers invited by journal 16 Aug, 2025 Editor assigned by journal 04 Aug, 2025 Submission checks completed at journal 04 Aug, 2025 First submitted to journal 29 Jul, 2025 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. 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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-7239099","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":504810786,"identity":"33424a94-0bf6-4fcd-b0d4-0ad5392f0eba","order_by":0,"name":"Yalian Li","email":"","orcid":"","institution":"Xinjiang Normal University","correspondingAuthor":false,"prefix":"","firstName":"Yalian","middleName":"","lastName":"Li","suffix":""},{"id":504810787,"identity":"9d88f93b-8152-4947-96c9-dec6b1ba3c50","order_by":1,"name":"Jinxuan Han","email":"","orcid":"","institution":"Merchants Xinjiang Testing Technology Research Institute Company Limited","correspondingAuthor":false,"prefix":"","firstName":"Jinxuan","middleName":"","lastName":"Han","suffix":""},{"id":504810788,"identity":"7b1c345d-9b11-4bc1-8295-2bd8fa70800c","order_by":2,"name":"Guozhu Li","email":"","orcid":"","institution":"Food and Drug Inspection Institute of the First Division of Xinjiang Production and Construction Corps","correspondingAuthor":false,"prefix":"","firstName":"Guozhu","middleName":"","lastName":"Li","suffix":""},{"id":504810789,"identity":"1f77a974-cb22-4013-8a64-62b571f92ae9","order_by":3,"name":"Honggang Zhao","email":"","orcid":"","institution":"Xinjiang Normal University","correspondingAuthor":false,"prefix":"","firstName":"Honggang","middleName":"","lastName":"Zhao","suffix":""},{"id":504810790,"identity":"4a546dc7-42a0-401c-b752-55a247c28337","order_by":4,"name":"Yuhua Ma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIie3QsYrCQBCA4ZHA2gymnWBIXmFtAgeCr7KLkE6wTGGRqLiFXG/hQ1heu01s9vqATewtYmchaHoliZ3F/vV8MDMANtsXxkKdlRVn6IZHXYpk0U4G5KxGu/nA93Y45aXJ20lA/c0Qq2DMC4i889rpsNgwqwmPEE5pnMiUgau2opn4evWz5zH29jov5J8PZP4PzQRkVlx4jg6IuJCGAadZK0kJ+QMZiGguN04HQnLpYf1kJBFBN4K6fnJNCM2UhMmx9ZZQqXNZ3dlkclT6eksWgat+m8lL+Nm4zWaz2d72BMoeSGSHf4JWAAAAAElFTkSuQmCC","orcid":"","institution":"Xinjiang Normal University","correspondingAuthor":true,"prefix":"","firstName":"Yuhua","middleName":"","lastName":"Ma","suffix":""},{"id":504810791,"identity":"2a979dbd-a40e-41f4-b4f7-2fc3e46891cf","order_by":5,"name":"Qingling Bai","email":"","orcid":"","institution":"Xinjiang Normal University","correspondingAuthor":false,"prefix":"","firstName":"Qingling","middleName":"","lastName":"Bai","suffix":""},{"id":504810792,"identity":"1812aff5-9e7e-4722-b7a0-1b65dd448bed","order_by":6,"name":"Zhicheng Wang","email":"","orcid":"","institution":"Xinjiang Normal University","correspondingAuthor":false,"prefix":"","firstName":"Zhicheng","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-07-29 05:08:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7239099/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7239099/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11164-025-05755-6","type":"published","date":"2025-10-29T15:58:45+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":90034740,"identity":"99d9ec34-d977-4b83-970a-bae112d82d6e","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1345426,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic diagram of the synthesis process of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite materials. SEM images of (b, e) HRP, (c, f) ZnWO\u003csub\u003e4\u003c/sub\u003e, and (d, g) ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite materials.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/030f3dbbe4af0dd49925fec0.png"},{"id":90034733,"identity":"76dd8a66-be8a-4039-abd5-67a29dfeebf9","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":97894,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD patterns. (b) FTIR spectra for HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/50aef24da7213bf93f1f403d.png"},{"id":90037227,"identity":"bd2b250e-6c27-4109-8896-00b58946fa09","added_by":"auto","created_at":"2025-08-27 16:04:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":168405,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XPS survey spectra and high-resolution spectra, (b) P 2p, (c) Zn 2p, and (d) W 4f for HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/090c189c65a1d8d76ddc37ce.png"},{"id":90035705,"identity":"25db4f9d-1a03-428e-b1bd-412274350f6f","added_by":"auto","created_at":"2025-08-27 15:48:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":100886,"visible":true,"origin":"","legend":"\u003cp\u003e(a) BET spectra, (b) pore size distribution profiles for HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/75ccc619c0caa83dc1ec8e94.png"},{"id":90034735,"identity":"601c37db-eac0-429a-9c7b-b38034c4e603","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":94998,"visible":true,"origin":"","legend":"\u003cp\u003e(a) UV-vis diffuse reflectance spectra for HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite. (b) M-S curves of HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/1d85531daef4ddd6ea87cc46.png"},{"id":90036752,"identity":"465a4a2d-5059-4729-b136-4d7fdd697886","added_by":"auto","created_at":"2025-08-27 15:56:45","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":85509,"visible":true,"origin":"","legend":"\u003cp\u003e(a) EIS spectra for HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP, and (b) I-T curves for HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/9657c46541d0169863d38535.png"},{"id":90034754,"identity":"9bddee43-eb76-4e98-9c19-6cca8c9bd2c5","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":237548,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Photodegradation of RhB curves, (b) kinetic curves, (c) Plot of cycling experiments, (d) Influence of active species scavenging agents on the photocatalytic activity of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/a84daf9e0875ce3079b04433.png"},{"id":90034747,"identity":"920990d1-9c52-4c03-8abe-7fd49e74a528","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":278257,"visible":true,"origin":"","legend":"\u003cp\u003e(a) II type heterojunction mechanism, (b) S-scheme heterojunction mechanism. (c) Photocatalytic mechanism of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/cf5cba1af239a8fd443b20f3.png"},{"id":95040558,"identity":"e91d3bc9-0d48-4128-927a-0dafb6990333","added_by":"auto","created_at":"2025-11-03 16:09:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3330207,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/cedbbe2c-1825-4f97-8d22-9a56ca412c71.pdf"},{"id":90034742,"identity":"f60ec83f-dafb-4269-9aa4-f6780deb040d","added_by":"auto","created_at":"2025-08-27 15:40:45","extension":"png","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":208007,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.png","url":"https://assets-eu.researchsquare.com/files/rs-7239099/v1/fb16d8d739ff1ba42cbb1d7a.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials","fulltext":[{"header":"Introduction","content":"\u003cp\u003eWater pollution control remains a critical research focus worldwide [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Photocatalytic technology holds significant potential for organic pollutant removal due to its low energy consumption and mild reaction conditions [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The development and synthesis of efficient semiconductor materials are pivotal for the practical implementation of photocatalytic technology [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, single-component semiconductors have many limitations in practical applications. The core problem lies in the low separation efficiency of photo-generated electrons and holes, which causes carriers to recombine rapidly[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These limitations hinder their widespread use. To improve the separation efficiency of charge carriers in single-layer semiconductor materials, researchers have developed a variety of control strategies, including the control of semiconductor size and morphology, ion doping, and the construction of heterostructures [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Among these, composite heterojunctions formed by integrating two complementary semiconductor materials can significantly enhance light absorption and facilitate photogenerated carrier separation/migration, thereby improving photocatalytic performance [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].In recent years, S-scheme heterojunctions-constructed by combining reduced-state photoactive materials with high conduction band positions and oxidized-state photocatalysts with low valence band positions-have garnered significant scientific attention [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Compared to other heterojunction types, S-scheme heterojunctions offer distinct advantages: they enable efficient electron-hole separation while preserving and enhancing the redox capacity of photocatalytic materials, making them highly effective for improving photocatalytic performance [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].Thus, identifying two semiconductor photocatalysts with matched energy band structures and constructing S-scheme heterojunctions between them is essential for optimizing the photocatalytic performance of single-component semiconductors[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eZnWO\u003csub\u003e4\u003c/sub\u003e has found extensive application in photocatalytic fields owing to its outstanding chemical stability and exceptional optical as well as electrochemical properties. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, surface hydroxyl groups formed in the synthesis process of ZnWO\u003csub\u003e4\u003c/sub\u003e may trigger hydrogen-related defects, which serve as locations for carrier trapping and recombination. This decreases the number of accessible carriers on the catalyst surface, consequently suppressing the formation of highly reactive superoxide radicals (·O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e) and hydroxyl radicals (·OH)[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. During photocatalysis, free radical production facilitates the decomposition of pollutants into CO\u003csub\u003e2\u003c/sub\u003e, water, and inorganic acids [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Therefore, suppressing hydrogen-related defects in ZnWO\u003csub\u003e4\u003c/sub\u003e is critical to enhancing its photocatalytic performance. Strategies to address this issue primarily involve constructing semiconductor heterojunctions, such as Type II (BiOBr/ZnWO\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]), Type Z (Ag\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e/ZnWO\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], ZnWO\u003csub\u003e4\u003c/sub\u003e/TiO\u003csub\u003e2\u003c/sub\u003e/MoS\u003csub\u003e2\u003c/sub\u003e [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]), which exhibit higher photocatalytic efficiencies than pure ZnWO\u003csub\u003e4\u003c/sub\u003e. However, reports on constructing S-scheme heterojunctions between ZnWO\u003csub\u003e4\u003c/sub\u003e and other semiconductors remain limited, making it essential to identify suitable partners for S-scheme heterostructure formation. Red phosphorus (RP), a common photoactive material, possesses a tunable bandgap (1.7–2.4 eV) and exhibits strong absorption of visible light with wavelengths up to 700 nm[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. However, rapid photogenerated carrier recombination significantly limits its photocatalytic performance [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Given the matched energy band structures of ZnWO\u003csub\u003e4\u003c/sub\u003e and hydrothermal red phosphorus (HRP), constructing stable heterojunctions is expected to mitigate their individual drawbacks and enhance overall photocatalytic performance.\u003c/p\u003e\u003cp\u003eIn this study, ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP S-scheme heterojunctions were prepared by combining HRP with ZnWO\u003csub\u003e4\u003c/sub\u003e via a green and simple hydrothermal method. Such an approach efficiently lessens hydrogen-related defects on ZnWO\u003csub\u003e4\u003c/sub\u003e surfaces while enhancing electron-hole pair separation efficiency, thus attaining optimal photocatalytic performance. Lastly, the photocatalytic mechanism for the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite was examined and deliberated.\u003c/p\u003e"},{"header":"Experimental section","content":"\u003cp\u003e\u003cb\u003eMaterials\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe chemical reagents involved in this study are commercially available and can be used directly without additional treatment. Among these, zinc nitrate and sodium tungstate dihydrate were obtained from Chengdu Kelong Chemical Reagent Factory. Ammonium oxalate, tert-butanol, and isopropanol (C\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e8\u003c/sub\u003eO) were provided by Tianjin Yongsheng Fine Chemicals Factory. Rhodamine B was obtained from Tianjin Tianxin Fine Chemical Development Center. Benzoquinone was supplied by Shanghai Third Reagent Factory. Anhydrous ethanol and acetone were likewise obtained from Tianjin Guangfu Technology Development Co. RP was acquired from Zhejiang Yongjia Fine Chemical Factory.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of ZnWO\u003c/b\u003e\u003csub\u003e\u003cb\u003e4\u003c/b\u003e\u003c/sub\u003e\u003cb\u003e/HRP composites photocatalysts\u003c/b\u003e\u003c/p\u003e\u003cp\u003eSynthesis of ZnWO\u003csub\u003e4\u003c/sub\u003e: 5 mmol of Na\u003csub\u003e2\u003c/sub\u003eWO\u003csub\u003e4\u003c/sub\u003e·2H\u003csub\u003e2\u003c/sub\u003eO and Zn(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e were dissolved in water, with the mixture being ultrasonically stirred for 30 min. And the solution was placed under hydrothermal reaction at 180°C for 24 h. Following the hydrothermal treatment, the obtained product was subjected to three rounds of washing, subsequently dried at 60°C, and was ultimately designated as ZnWO\u003csub\u003e4\u003c/sub\u003e.\u003c/p\u003e\u003cp\u003eSynthesis of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites: HRP was treated according to reference [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. A specific quantity of ZnWO\u003csub\u003e4\u003c/sub\u003e and HRP were milled for 30 min, after which hydrothermal treatment was carried out at 150°C. After hydrothermal treatment, the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites were dried at 60°C.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCharacterization of photocatalysts\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn this study, multiple characterization techniques were employed to conduct a comprehensive analysis of the various properties of the samples. The microscopic morphology of the samples was examined with a Zeiss SIGMA 300 scanning electron microscope (SEM). The crystalline structural characteristics of the samples were ascertained using a Bruker D8 Advance X-ray diffractometer (XRD). The molecular structure and functional groups of the samples were characterized using a TENSOR27 model Fourier transform infrared spectrometer (FT-IR). X-ray photoelectron spectroscopy (XPS) measurements were conducted using a Thermo Fisher ESCALAB 250Xi X-ray photoelectron spectrometer equipped with a monochromatic Al Kα excitation source. The specific surface area and pore size distribution of the samples were determined with a Micromeritics ASAP 2460 physisorption analyzer. Data for ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) were collected by a Shimadzu UV-3600i Plus spectrophotometer. Electrochemical tests were carried out on a CHI660C electrochemical workstation, utilizing a three-electrode system that included an indium tin oxide (ITO) working electrode, a platinum wire counter electrode, and a saturated Ag/AgCl reference electrode.\u003c/p\u003e\u003cp\u003e\u003cb\u003ePhotoelectrochemical detection\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe photocurrent response characteristics (I-T) and electrochemical impedance spectroscopy (EIS) of the samples were tested and characterized using a CHI660E electrochemical workstation. The experiments were conducted under 300 W xenon light illumination with a standard three-electrode system: the target photocatalyst-modified electrode functioned as the working electrode, a platinum wire electrode served as the auxiliary electrode, and an Ag/AgCl electrode immersed in a saturated KCl solution acted as the reference electrode. The electrolyte employed was a 0.5 mol/L sodium sulphate aqueous solution. The specific preparation process for the working electrode was as follows: 5 mg of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite catalyst was taken and mixed with Nafion and ethanol solution at a volume ratio of 1:19; 40 µL of the mixed dispersion was transferred, sonicated until the system became uniform, and then uniformly coated onto the surface of a 1.0 cm\u003csup\u003e2\u003c/sup\u003e indium tin oxide (ITO) conductive glass substrate; the prepared electrode was placed in a 60°C environment and dried for 2 h to ensure that the catalyst particles were firmly loaded onto the ITO substrate surface.\u003c/p\u003e\u003cp\u003e\u003cb\u003ePhotocatalytic experiment\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA 300-watt xenon lamp (equipped with a UV filter, with a light intensity of 140 mW/cm\u003csup\u003e2\u003c/sup\u003e) was employed as the light source for the photocatalytic reaction, and a 10 mg/L Rhodamine B (RhB) solution served as the target pollutant for degradation. The specific experimental procedure was as follows: 5.0 mg of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite material was mixed with 20 mL of RhB solution. Following ultrasonic treatment to achieve uniform dispersion of the system, the mixture was placed in a dark environment and magnetically stirred for 30 min to ensure adequate dispersion of the catalyst and attain adsorption-desorption equilibrium at the solid-liquid interface. Throughout the reaction, samples were collected at regular time intervals. The reaction solution was centrifuged, and the absorbance of the resulting supernatant was determined at 554 nm using a UV-visible spectrophotometer.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003e\u003cb\u003eCharacterization of photoelectroactive materials\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite was successfully synthesized through a straightforward hydrothermal approach (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). We used scanning electron microscopy (SEM) to study the microstructure of photocatalysts. HRP displayed relatively large particle dimensions, a rough surface, and irregular shapes, with particles arranged closely together visible under high magnification (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb, e). Pristine ZnWO\u003csub\u003e4\u003c/sub\u003e formed obvious agglomerates with smooth surfaces and consisted of irregularly stacked nanorods as observed at 10x magnification (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, f). By comparison, the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite consists of numerous small particles with excellent dispersibility that adhere evenly to the HRP surface, thus creating a more prominent and ordered porous structure (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed, g). This structure promoted the efficient separation and migration of photo-generated charge carriers on the catalyst surface, thereby significantly enhancing the photocatalytic performance of semiconductor materials[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]。\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe crystal structure and phase purity of the photocatalyst were analyzed using powder X-ray diffraction (XRD) patterns (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). A distinct diffraction peak at 2θ\u0026thinsp;=\u0026thinsp;15.3\u0026deg; was observed in pure HRP, corresponding to the (102) crystal plane of amorphous RP. This result matched the characteristic diffraction peak documented in the literature (JCPDS No. 44\u0026ndash;0904) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The XRD spectra of ZnWO\u003csub\u003e4\u003c/sub\u003e were highly consistent with the JCPDS standard card (JCPDS No. 73\u0026ndash;0554) [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The diffraction patterns of the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite samples retained the complete diffraction features of ZnWO\u003csub\u003e4\u003c/sub\u003e and clearly displayed the characteristic peaks of HRP\u0026rsquo;s (102) crystalline facet, confirming the successful preparation of the composites. Notably, the characteristic peak at 2θ\u0026thinsp;=\u0026thinsp;15\u0026deg; for the composite catalyst appeared sharper than that of pure HRP. This suggested that the combination of ZnWO\u003csub\u003e4\u003c/sub\u003e and HRP led to improved crystallinity of the material, along with enhanced ordering in atomic arrangement.\u003c/p\u003e\u003cp\u003eWe used Fourier transform infrared spectroscopy (FT-IR) to study the functional group structure of photocatalysts (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). The absorption peaks at 1008, 1160, and 1634 cm\u003csup\u003e\u0026minus;\u003c/sup\u003e1 were attributed to the stretching vibrations of P-P-O, P\u0026thinsp;=\u0026thinsp;O, and P-O, respectively [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The characteristic absorption peaks at 584 and 831 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e could be attributed to the W-O vibration band in the WO₆ octahedron, while the peak at 716 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e belonged to the Zn-O-W vibration band [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Notably, within the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite, the bond strength of W-O and Zn-O-W dropped markedly, a phenomenon that could have been linked to chemical bond changes induced by interfacial interactions. The hydroxyl groups on the sample surface formed during hydrothermal synthesis correspond to the 1634 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e absorption peak, and such hydroxyl groups might induce the formation of hydrogen-related defects [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The absorption peak at 1383 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was directly related to hydrogen-related defects on the surface of ZnWO\u003csub\u003e4\u003c/sub\u003e [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. These defects were prone to becoming photogenerated carrier recombination centers, thereby reducing photocatalytic efficiency [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Compared with pure ZnWO\u003csub\u003e4\u003c/sub\u003e, the composite exhibits significantly lower peak intensity at 1383 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, indicating a reduction in hydrogen-related defects. It was speculated that HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e effectively eliminate surface defects through chemical bonding. Reducing the exposure to hydrogen-related defects could suppress carrier recombination, improve charge transfer efficiency, and promote the separation of photo-generated electron-hole pairs [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eX-ray photoelectron spectroscopy (XPS) was used to study the elemental composition and valence state changes of the catalyst. The complete XPS spectrum showed that elements such as P, Zn, W, C, and O were present in the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite material (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). Of these, P was linked to HRP, whereas Zn and W were linked to ZnWO\u003csub\u003e4\u003c/sub\u003e. This verified the correct elemental proportion of HRP to ZnWO\u003csub\u003e4\u003c/sub\u003e, with no other impurities detected. A more thorough examination of the chemical valence states of elements was performed via XPS fine spectroscopy: within the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite, the 2p\u003csub\u003e3/2\u003c/sub\u003e and 2p\u003csub\u003e1/2\u003c/sub\u003e binding peaks of P were situated at 129.4 eV and 130.2 eV, in that order, corresponding to elemental P (P\u003csub\u003e0\u003c/sub\u003e) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb) [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The binding energy peaks of Zn 2p\u003csub\u003e3/2\u003c/sub\u003e and 2p\u003csub\u003e1/2\u003c/sub\u003e were observed at 1022.7 and 1045.9 eV, respectively, indicating that zinc was in the +\u0026thinsp;2 valence state (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec) [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Furthermore, the W 4f\u003csub\u003e7/2\u003c/sub\u003e and W 4f\u003csub\u003e5/2\u003c/sub\u003e binding peaks were positioned at 36.3 and 38.5 eV, respectively, demonstrating that W existed in the +\u0026thinsp;6 oxidation state (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed) [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Notably, the P 2p binding energy peak in ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP was lower than that in HRP, which suggested that electron cloud density of the P element had risen. In contrast, Zn 2p and W 4f in the composite shift toward higher binding energies compared to pure ZnWO\u003csub\u003e4\u003c/sub\u003e, showing an opposite trend to that of HRP. These changes revealed electron transfer from ZnWO\u003csub\u003e4\u003c/sub\u003e to HRP, with this transfer arising from the strong interfacial chemical interaction between them. These interactions promoted charge transfer at the interface, significantly improving the separation and transfer efficiency of photo-generated electron-hole pairs, thereby enhancing the photoelectrochemical performance of the composite material [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. The combined findings from characterization derived from SEM, XRD, FT-IR, and XPS verified the successful synthesis of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction materials.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe specific surface area and pore size characteristics of the photocatalyst were characterized using nitrogen adsorption-desorption isotherms and pore size distribution analysis. The N\u003csub\u003e2\u003c/sub\u003e adsorption-desorption isotherms of HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite materials all exhibited Type IV isotherm characteristics, indicating that all three materials possessed mesoporous structures (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). The specific surface area of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP (29.855 m\u003csup\u003e2\u003c/sup\u003e/g) exceeded that of HRP (2.037 m\u003csup\u003e2\u003c/sup\u003e/g) and ZnWO\u003csub\u003e4\u003c/sub\u003e (27.578 m\u003csup\u003e2\u003c/sup\u003e/g). Additionally, the pore size distribution curves indicated that the pore volumes of HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP were 0.016, 0.103, and 0.109 cm\u003csup\u003e3\u003c/sup\u003e/g, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). A greater specific surface area not only aided in generating photogenerated carriers during the photocatalytic process but also enabled them to take part in photocatalytic reactions more effectively, thereby enhancing the photocatalytic performance of the composite materials[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe light absorption characteristics of the photocatalysts were studied using ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). Pure ZnWO\u003csub\u003e4\u003c/sub\u003e showed an absorption edge near 400 nm, which indicated that its absorption was mainly focused in the ultraviolet range, while its absorption in the visible region (λ\u0026thinsp;\u0026ge;\u0026thinsp;400 nm) was nearly negligible. Compared with ZnWO\u003csub\u003e4\u003c/sub\u003e, the absorption edges of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP samples underwent an obvious red shift, suggesting that the composite material absorbs more visible light, generating additional electrons and holes. After compositing ZnWO\u003csub\u003e4\u003c/sub\u003e with HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP demonstrates strong visible light absorption, with its absorption edge generally between those of HRP (around 690 nm) and ZnWO\u003csub\u003e4\u003c/sub\u003e. This demonstrated that the heterostructure formed between HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e further expanded the light absorption range of the composite, thus enhancing its light utilization efficiency and actively facilitating the photocatalytic reaction. Generally speaking, the band gap (E\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e) of semiconductor materials could be calculated using the Tauc equation:\u003c/p\u003e\u003cp\u003e(αhv)\u003csup\u003e1/n\u003c/sup\u003e = A (hv - E\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e) (1)\u003c/p\u003e\u003cp\u003eh is Planck's constant, α is the absorption coefficient, E\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e is the bandgap energy, ν is the frequency of light, A is a constant, and n depends on the type of electron transition in the semiconductor: n\u0026thinsp;=\u0026thinsp;1/2 for direct bandgap semiconductors and n\u0026thinsp;=\u0026thinsp;2 for indirect bandgap semiconductors. Therefore, the calculated E\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e values for HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e were 1.8 and 3.1 eV, respectively.\u003c/p\u003e\u003cp\u003eThe band structure of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP was further characterized using the Mott-Schottky measurement method (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb). The flat band potentials (E\u003csub\u003eFB\u003c/sub\u003e) of HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e were obtained from the intersection of the tangent line with the x-axis, being \u0026minus;\u0026thinsp;1.08 and \u0026minus;\u0026thinsp;0.85 V (\u003cem\u003evs.\u003c/em\u003e Ag/AgCl), respectively. These potentials were then converted to standard hydrogen electrode (NHE) potentials using the following formula (2).:\u003c/p\u003e\u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u003csub\u003e\u003cem\u003eFB\u003c/em\u003e\u003c/sub\u003e (vs. NHE)\u0026thinsp;=\u0026thinsp;\u003cem\u003eE\u003c/em\u003e\u003csub\u003e\u003cem\u003eFB\u003c/em\u003e\u003c/sub\u003e (pH\u0026thinsp;=\u0026thinsp;0, vs. Ag/AgCl)\u0026thinsp;+\u0026thinsp;\u003cem\u003eE\u003c/em\u003e\u003csub\u003e\u003cem\u003eAgCl\u003c/em\u003e\u003c/sub\u003e + 0.059 \u0026times; pH (2)\u003c/p\u003e\u003cp\u003eHere, E\u003csub\u003eAgCl\u003c/sub\u003e equals 0.197 V and the electrolyte pH is 7. The EFB values for HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e (\u003cem\u003evs.\u003c/em\u003e NHE) were calculated to be -0.47 and \u0026minus;\u0026thinsp;0.22 V, respectively. The positive slope of the HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e curves indicated that both were n-type semiconductors. For n-type semiconductors, the conduction band potential (E\u003csub\u003eCB\u003c/sub\u003e) was approximately 0.1 V higher than the flat band potential (\u003cem\u003evs.\u003c/em\u003e NHE) [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Thus, the E\u003csub\u003e\u003cem\u003eCB\u003c/em\u003e\u003c/sub\u003e values of HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e stood at -0.57 and \u0026minus;\u0026thinsp;0.32 V (\u003cem\u003evs.\u003c/em\u003e NHE) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Using the formula E\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e = E\u003csub\u003eVB\u003c/sub\u003e - E\u003csub\u003eCB\u003c/sub\u003e, the valence band potentials (E\u003csub\u003eVB\u003c/sub\u003e) of HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e were calculated to be 1.23 and 2.78 V (\u003cem\u003evs.\u003c/em\u003e NHE), respectively.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eElectrochemical impedance spectroscopy (EIS), as a precise technique for studying electrode process kinetics and surface phenomena, holds significance in electrochemical testing (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea). To deeply analyze the electrochemical behavior of the photoactive materials, EIS tests were conducted on HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites. All samples displayed circular patterns, yet the EIS arc radius of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP was notably smaller than that of pure HRP samples. Generally speaking, in electrochemical impedance spectroscopy (EIS), the smaller the arc radius, the lower the electrode impedance and the higher the internal charge transfer efficiency [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. The low impedance of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP provides strong evidence for enhanced conductivity within the heterostructures. In summary, the HRP/ZnWO\u003csub\u003e4\u003c/sub\u003e composite promoted the rapid transfer and effective separation of photogenerated carriers, thereby enhancing its photocatalytic activity.\u003c/p\u003e\u003cp\u003eTransient photocurrent (I-T) measurements were utilized to determine the photoelectrochemical characteristics of these catalysts (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb), which visualizes the photogenerated carrier transport properties and separation efficiency. All materials showed a stable transient photocurrent response under light/dark conditions [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]: When the light source was turned on, the photocurrent increased rapidly; when the light source was blocked, the photocurrent decreased rapidly. Under the same conditions, the photocurrent of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP reached 0.16 \u0026micro;A/cm\u003csup\u003e2\u003c/sup\u003e, twice that of pure ZnWO\u003csub\u003e4\u003c/sub\u003e (0.08 \u0026micro;A/cm\u003csup\u003e2\u003c/sup\u003e) and 1.3 times that of pure HRP (0.12 \u0026micro;A/cm\u003csup\u003e2\u003c/sup\u003e), indicating its superior photo-responsive ability and higher generation of photogenerated carriers, which provided sufficient charge carriers to enhance the reaction efficiency. Moreover, the patterns of current variation exhibited by HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP were uniform, a finding that verified the stability of these materials. In conclusion, the HRP/ ZnWO\u003csub\u003e4\u003c/sub\u003e heterojunction significantly enhanced electron-hole separation ability, making its photocatalytic activity superior to that of single materials.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003ePhotocatalytic degradation of RhB\u003c/b\u003e\u003c/p\u003e\u003cp\u003eUsing Rhodamine B (RhB) as a pollutant, the photocatalytic performance of the synthesized ZnWO₄/HRP photocatalyst was evaluated (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea). First, HRP, ZnWO\u003csub\u003e4\u003c/sub\u003e, and ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP were stirred in the dark for 30 min to achieve adsorption-desorption equilibrium. Subsequently, visible light irradiation was applied, and it was observed that the concentration of RhB slowly decreased with increasing reaction time. Notably, ZnWO\u003csub\u003e4\u003c/sub\u003e exhibited only 6.6% RhB degradation after 15 min of light irradiation, as its wide bandgap significantly reduced visible light utilization and consequently affected photodegradation ability. HRP achieved 62.5% RhB degradation within 15 min due to its effective visible light response. In contrast, the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction composite catalyst exhibited excellent degradation performance, with a degradation rate of 95.5% for RhB after 15 min of illumination. In addition, dynamic studies of the photodegradation process indicated that the degradation of RhB followed a pseudo-first-order kinetic model (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb). The reaction rate (κ) of the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction was 0.21 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which was 3.5 times higher than that of HRP (0.06 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and 21 times higher than that of ZnWO\u003csub\u003e4\u003c/sub\u003e (0.01 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). This result indicated that the synergistic effects within the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction not only enhanced ZnWO\u003csub\u003e4\u003c/sub\u003e's response to visible light but also promoted the separation and transfer of photo-generated carriers while effectively suppressing carrier recombination.\u003c/p\u003e\u003cp\u003eCatalyst stability was a key indicator for evaluating the performance of photoelectrically active materials[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. The photocatalytic stability was tested via multiple rounds of cyclic degradation tests using a 10 mg/L RhB solution (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ec). The photodegradation efficiency of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP toward RhB slightly decreased from 95.4\u0026ndash;89.7% within 15 min after five cycling tests. Degradation efficiency's slight decline could have resulted from the loss of photoactive materials in cyclic tests. This research demonstrated that ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP could function as a stable and highly effective photoactive material for repeatedly degrading pollutants.\u003c/p\u003e\u003cp\u003eFurther experiments were conducted to capture the active substances involved in the photocatalytic reaction of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ed). Ammonium oxalate (AO), isopropyl alcohol (IPA), and p-benzoquinone (PBQ) were used as scavengers to capture holes, \u0026middot;OH, and \u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, respectively. Under simulated sunlight irradiation, ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites achieved 95.5% RhB photodegradation within 15 min. When PBQ was added, RhB photodegradation by ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP decreased from 95.4\u0026ndash;57.8%; in contrast, adding the hole scavenger AO caused the degradation rate to drop directly to 46.1%. After adding IPA, the photodegradation rate did not decrease significantly, indicating that \u0026middot;OH was not the main active substance in the photodegradation process of RhB. All results suggest that holes play the most critical role in the RhB photodegradation reaction, while\u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e also serves as a relatively important intermediate active species.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eInvestigation of the mechanism\u003c/b\u003e\u003c/p\u003e\u003cp\u003eBased on the above discussion, a potential mechanism for the photocatalytic degradation of RhB by ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction photocatalysts was proposed (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ea and b). If ZnWO\u003csub\u003e4\u003c/sub\u003e formed a Type II heterojunction with HRP, electrons would migrate from the CB of HRP to ZnWO\u003csub\u003e4\u003c/sub\u003e, while holes would migrate from the VB of ZnWO\u003csub\u003e4\u003c/sub\u003e to HRP. However, according to the M-S curve and the Kubelka-Munk equation, the valence band potential of HRP (1.23 V) was lower than the redox potential of \u0026middot;OH/OH⁻ (1.99 V), making it unable to oxidize OH⁻ to \u0026middot;OH; additionally, the conduction band potential of ZnWO\u003csub\u003e4\u003c/sub\u003e was higher than the redox potential of O\u003csub\u003e2\u003c/sub\u003e/\u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, so it could not produce more \u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e than HRP. These results contradicted the pre-assumed Type II heterojunction mechanism and instead aligned with a new S-scheme heterojunction. Therefore, a mechanism for the photocatalytic degradation of RhB via a ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP S-scheme heterojunction had been proposed (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ec). Under visible light irradiation, photogenerated electrons and holes were produced in HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e. Electrons within ZnWO\u003csub\u003e4\u003c/sub\u003e's CB would move to the VB of HRP, whereas holes in ZnWO\u003csub\u003e4\u003c/sub\u003e's VB and electrons in HRP's CB would gather at the interface. These accumulated electrons would reduce oxygen to \u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, and certain holes would oxidize water to \u0026middot;OH. The excellent rhodamine B degradation efficiency exhibited by the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite photocatalyst was closely related to the S-scheme heterojunction it formed. This mechanism enhanced the spatial separation and migration ability of photo-generated electron-hole pairs, broadened the light absorption range, and promoted the generation of more active substances on the catalyst surface, thereby accelerating the degradation of pollutants. Overall, these findings verified that the ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite functioned as a highly effective and stable photocatalyst for water remediation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this study, the preparation of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction photocatalysts was achieved by means of a simple hydrothermal approach. The rod-shaped ZnWO\u003csub\u003e4\u003c/sub\u003e was evenly adhered to the HRP surface, thereby forming a tightly-bonded interface. Moreover, it demonstrated remarkable efficacy in the photocatalytic removal of contaminants. The rate of photodegradation of RhB could reach 0.21 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in just 15 min. This rate was approximately 3.5 times that of HRP (0.06 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and 21 times that of ZnWO\u003csub\u003e4\u003c/sub\u003e (0.01 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). The enhancement in photocatalytic efficiency could be attributed to the formation of S-scheme heterojunctions. This heterojunction inhibited the hydrogen-related defects on the ZnWO\u003csub\u003e4\u003c/sub\u003e surface. The suppression of hydrogen-related defects reduced the surface defect state, which effectively inhibited the surface carrier recombination and accelerated the charge transfer. By resolving the issue of hydrogen-related defects and improving carrier separation, the composite achieves outstanding photocatalytic efficiency and stability. The visible light absorption range, photoelectric conversion efficiency, and photocatalytic activity of ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composites were significantly enhanced. The synthesized ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP composite serves as a highly efficient visible-light catalyst, presenting extensive application prospects.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e This work was financially supported by Xinjiang Uygur Autonomous Region Division and Municipal Financial Science and Technology Program Projects (2024GX07), Key Research and Development Plan Project of Karamay District (2025kqzdyf0024), Autonomous Region Market Supervision and Management Science and Technology (2024152521), \u0026ldquo;Tianshan Talent\u0026rdquo; - Youth Top notch Talent Project (2024TSYCCX0067), Natural Science Foundation of Xinjiang Uygur Autonomous Region (2024D01B59, 2024D01A104), \u0026ldquo;Tianchi Talent\u0026rdquo; Introduction Program for Young Doctors funded by the Talent Development Fund of Xinjiang Uygur Autonomous Region, The Second Batch of \u0026ldquo;Tianchi Talent\u0026rdquo; Young Doctor Introduction Program of Xinjiang Uygur Autonomous Region (601002000102), Scientific Research Project of Basic Scientific Research Funds for Universities in Xinjiang Uygur Autonomous Region (XJEDU2025P070), Xinjiang Normal University 2022 Young Top Talent Project (XJNUQB2022-25), Doctoral Scientific Research Start-up Fund of Xinjiang Normal University (XJNUBS2305) and College Students\u0026rsquo; Innovative Entrepreneurial Training (S202410762010, S202410762012, X202410762117).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e Yalian Li: Data curation, Writing - original draft, Conceptualization. Jinxuan Han：\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eProject administration.\u0026nbsp;Guozhu Li:\u0026nbsp;Data curation.\u0026nbsp;Honggang Zhao:\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eWriting - review \u0026amp; editing. Yuhua Ma:\u0026nbsp;Funding acquisition.\u0026nbsp;Qingling Bai:\u0026nbsp;Conceptualization.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eZhicheng Wang: Software.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e Data will be made available on request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJ. Li, D. Wang, S. Zhao, R. Ma, J. Guo, Z. Li, D. Wang, Y. Xuan and L. Wang, Appl. Catal. B. \u003cstrong\u003e351\u003c/strong\u003e, 124007 (2024).\u003c/li\u003e\n\u003cli\u003eF. Bi, Z. Zheng, R. Li, R. Du, L. Zhao, S. Xiao, L. Wang and X. Dong, Chem. Eng. J. \u003cstrong\u003e507\u003c/strong\u003e, 160781 (2025).\u003c/li\u003e\n\u003cli\u003eX. Duan, H. Jia and T. Cao, Appl. Catal. B. \u003cstrong\u003e352\u003c/strong\u003e, 124016 (2024).\u003c/li\u003e\n\u003cli\u003eQ. Su, J. Li and B. Wang, Appl. Catal. B. \u003cstrong\u003e318\u003c/strong\u003e, 121820 (2022).\u003c/li\u003e\n\u003cli\u003eY. Zhao, Y. Zhang, L. Wang, C. Ai and J. Zhang, J. Mater. Sci. Technol. \u003cstrong\u003e229\u003c/strong\u003e, 213 (2025).\u003c/li\u003e\n\u003cli\u003eY. Ai, J. Hu, X. Xiong, S. A. C. Carabineiro, Y. Li, N. Sirotkin, A. Agafonov and K. Lv, Appl. Catal. B. \u003cstrong\u003e353\u003c/strong\u003e, 124098 (2024).\u003c/li\u003e\n\u003cli\u003eX. Zou, B. Sun and L. Wang, Chem. Eng. J. \u003cstrong\u003e482\u003c/strong\u003e, 148818 (2024).\u003c/li\u003e\n\u003cli\u003eC. Pinming, Q. Yang, N. Kayunkid, V. Yordsri, W. Wongwiriyapan and Y. J. Song, J. Mater. Chem. A \u003cstrong\u003e13\u003c/strong\u003e(14), 9811 (2025).\u003c/li\u003e\n\u003cli\u003eA. H. Navidpour, J. Safaei and M. A. H. Johir, Adv. Compos. Hybrid Mater. \u003cstrong\u003e7\u003c/strong\u003e(2), 53 (2024).\u003c/li\u003e\n\u003cli\u003eR. Wu, S. Gao, C. Jones, M. Sun, M. Guo, R. Tai, S. Chen and Q. Wang, Adv. Funct. Mater. \u003cstrong\u003e34\u003c/strong\u003e(24), 2314051 (2024).\u003c/li\u003e\n\u003cli\u003eY. Ma, X. Aihemaiti, K. Qi, S. Wang, Y. Shi, Z. Wang, M. Gao, F. Gai and Y. Qiu, J. Mater. Sci. Technol. \u003cstrong\u003e156\u003c/strong\u003e, 217 (2023).\u003c/li\u003e\n\u003cli\u003eZ. Liu, H. Luo, M. Zhang, Y. Mu, F. Bai, M. Zhang and T. Lu, Chem. Eng. J. \u003cstrong\u003e491\u003c/strong\u003e, 151913 (2024).\u003c/li\u003e\n\u003cli\u003eN. Li, Y. Niu, W. An, F. Ruan, H. Wu, B. Hui, Y. Wang and G. Fan, Appl. Catal. B. \u003cstrong\u003e369\u003c/strong\u003e, (2025).\u003c/li\u003e\n\u003cli\u003eC. You, X. Zhang, Y. Zhao, R. Yan, Y. Shen, Q. Xue, W. Li, T. Liu, J. Jiang, X. Chen and S. Li, J. Mater. Sci. Technol. \u003cstrong\u003e242\u003c/strong\u003e, 64 (2025).\u003c/li\u003e\n\u003cli\u003eX. Wang, S. Yu, Z.-H. Li, L.-L. He, Q.-L. Liu, M.-Y. Hu, L. Xu, X.-F. Wang and Z. Xiang, Chem. Eng. J. \u003cstrong\u003e405\u003c/strong\u003e, 126922 (2021).\u003c/li\u003e\n\u003cli\u003eR. Shi, Y. Wang, D. Li, J. Xu and Y. Zhu, Appl. Catal. B. \u003cstrong\u003e100\u003c/strong\u003e(1-2), 173 (2010).\u003c/li\u003e\n\u003cli\u003eR. Peter, K. Salamon, A. Omerzu, J. Grenzer, I. J. Badovinac, I. Saric and M. Petravic, J. Phys. Chem. C. \u003cstrong\u003e124\u003c/strong\u003e(16), 8861 (2020).\u003c/li\u003e\n\u003cli\u003eA. O. C. Andrade, L. H. d. S. Lacerda, M. M. Lage J\u0026uacute;nior, S. K. Sharma, M. E. H. Maia da Costa, O. C. Alves, E. C. S. Santos, C. C. dos Santos, A. S. de Menezes, M. A. San-Miguel, F. M. Filho, E. Longo and M. A. P. Almeida, Opt. Mater. \u003cstrong\u003e138\u003c/strong\u003e, 113701 (2023).\u003c/li\u003e\n\u003cli\u003eJ. Zhang, J. Ma, X. Sun, Z. Yi, T. Xian, X. Wu, G. Liu, X. Wang and H. Yang, Langmuir \u003cstrong\u003e39\u003c/strong\u003e(3), 1159 (2023).\u003c/li\u003e\n\u003cli\u003eH. Zhang, X. Liu, Z. Li, F. Wang, J. Zhang, F. Gao, P. Zhang and Z. Wei, J. Mater. Sci. Technol. \u003cstrong\u003e59\u003c/strong\u003e(1), 38 (2023).\u003c/li\u003e\n\u003cli\u003eF. Liu, R. Shi, Z. Wang, Y. Weng, C. M. Che and Y. Chen, Angew. Chem., Int. Ed. \u003cstrong\u003e58\u003c/strong\u003e(34), 11791 (2019).\u003c/li\u003e\n\u003cli\u003eY. Wang, J. Wu and Y. Yan, Chem. Eng. J. \u003cstrong\u003e403\u003c/strong\u003e, 126313 (2021).\u003c/li\u003e\n\u003cli\u003eX. Aihemaiti, X. Wang, Y. Li, Y. Wang, L. Xiao, Y. Ma, K. Qi, Y. Zhang, J. Liu and J. Li, Chemosphere. \u003cstrong\u003e296\u003c/strong\u003e, 134013 (2022).\u003c/li\u003e\n\u003cli\u003eM. Selvamani, A. Alsulmi, A. Sundaramoorthy, S. Vadivel and A. V. Kesavan, J Mater Sci-Mater El. \u003cstrong\u003e34\u003c/strong\u003e(31), 2094 (2023).\u003c/li\u003e\n\u003cli\u003eX. Shi, Q. Chen, X. Qin, X. Rao, S. Li, G. Liu, J. Wang, X. Dong, D. Luo and F. Chen, Energy Environ. Mater. \u003cstrong\u003e8\u003c/strong\u003e(4), 70006 (2025).\u003c/li\u003e\n\u003cli\u003eX. Ren, D. Philo, Y. Li, L. Shi, K. Chang and J. Ye, Coord. Chem. Rev. \u003cstrong\u003e424\u003c/strong\u003e, 213516 (2020).\u003c/li\u003e\n\u003cli\u003eL. Zhen, Z. Yulian, L. Wen, C. Chunxu and Z. Jinfeng, Mater. Sci. Semicond. Process. \u003cstrong\u003e160\u003c/strong\u003e, 107445 (2023).\u003c/li\u003e\n\u003cli\u003eG. Jia, M. Sun, Y. Wang, X. Cui, B. Huang and J. C. Yu, Adv. Funct. Mater. \u003cstrong\u003e33\u003c/strong\u003e(10), 2212051 (2022).\u003c/li\u003e\n\u003cli\u003eB. Barik, M. Mishra and P. Dash, Environ. Sci.:Nano. \u003cstrong\u003e8\u003c/strong\u003e(9), 2676 (2021).\u003c/li\u003e\n\u003cli\u003eY. Cui, L. Pan, Y. Chen, N. Afzal, S. Ullah, D. Liu, L. Wang, X. Zhang and J.-J. Zou, RSC Adv. \u003cstrong\u003e9\u003c/strong\u003e(10), 5492 (2019).\u003c/li\u003e\n\u003cli\u003eF. Chen, S. Sun, K. Mu, Y. Li, Z. Shen and S. Zhan, Appl. Catal. B. \u003cstrong\u003e312\u003c/strong\u003e, 121373 (2022).\u003c/li\u003e\n\u003cli\u003eZ. Li, T. Yu, Z. Zou and J. Ye, Appl. Phys. Lett. \u003cstrong\u003e88\u003c/strong\u003e(7), 071917 (2006).\u003c/li\u003e\n\u003cli\u003eS. Zhan, F. Zhou, N. Huang, Q. He and Y. Zhu, Chem. Eng. J. \u003cstrong\u003e330\u003c/strong\u003e, 635 (2017).\u003c/li\u003e\n\u003cli\u003eJ. Liu, Y. Zhu, J. Chen, D. S. Butenko, J. Ren, X. Yang, P. Lu, P. Meng, Y. Xu, D. Yang and S. Zhang, J. Hazard. Mater. \u003cstrong\u003e413\u003c/strong\u003e, 125462 (2021).\u003c/li\u003e\n\u003cli\u003eD. Sun, Q. Wang, W. Wang, Y. Chen and S. Ruan, ACS Appl. Nano Mater. \u003cstrong\u003e6\u003c/strong\u003e(12), 10581 (2023).\u003c/li\u003e\n\u003cli\u003eM. R. Tamtam, R. Koutavarapu and J. Shim, Environ. Res. \u003cstrong\u003e227\u003c/strong\u003e, 115735 (2023).\u003c/li\u003e\n\u003cli\u003eM. Dai, Z. He, P. Zhang, X. Li and S. Wang, J. Mater. Sci. Technol. \u003cstrong\u003e122\u003c/strong\u003e, 231 (2022).\u003c/li\u003e\n\u003cli\u003eH. Zhuang, W. Xu, L. Lin, M. Huang, M. Xu, S. Chen and Z. Cai, J. Mater. Sci. Technol. \u003cstrong\u003e35\u003c/strong\u003e(10), 2312 (2019).\u003c/li\u003e\n\u003cli\u003eP. Li, J. Guo, X. Ji, Y. Xiong, Q. Lai, S. Yao, Y. Zhu, Y. Zhang and P. Xiao, \u0026quot;Construction of direct Z-scheme photocatalyst by the interfacial interaction of WO\u003csub\u003e3\u003c/sub\u003e and SiC to enhance the redox activity of electrons and holes Chemosphere \u003cstrong\u003e282\u003c/strong\u003e, 130866 (2021).\u003c/li\u003e\n\u003cli\u003eW. Chen, L. Chang, S. B. Ren, Z. C. He, G. B. Huang and X. H. Liu, \u0026quot;Direct Z-scheme 1D/2D WO\u003csub\u003e2.72\u003c/sub\u003e/ZnIn\u003csub\u003e2\u003c/sub\u003eS\u003csub\u003e4\u003c/sub\u003e hybrid photocatalysts with highly-efficient visible-light-driven photodegradation towards tetracycline hydrochloride removal J. Hazard. Mater. \u003cstrong\u003e384\u003c/strong\u003e, 121308 (2020).\u003c/li\u003e\n\u003cli\u003eG. Aimaiti, Y. Zou, Y. Ma, Y. Shi, K. Qi, W. Zhan, Z. Qian, Z. Liu and Y. Dong, Chem. Eng. J. \u003cstrong\u003e496\u003c/strong\u003e, 153852 (2024).\u003c/li\u003e\n\u003cli\u003eY. Zhao, H. Cui, Y. Hu, S. Li, F. Liu, B. Shen, K. Ge, B. Liu and Y. Yang, Appl. Catal. B. \u003cstrong\u003e361\u003c/strong\u003e, 124567 (2025).\u003c/li\u003e\n\u003cli\u003eZ. Xu, Q. Duan and X. Cui, Chem. Eng. J. \u003cstrong\u003e511\u003c/strong\u003e, (2025).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"research-on-chemical-intermediates","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"rint","sideBox":"Learn more about [Research on Chemical Intermediates](http://link.springer.com/journal/11164)","snPcode":"11164","submissionUrl":"https://submission.nature.com/new-submission/11164/3","title":"Research on Chemical Intermediates","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Photocatalysis, S-scheme heterojunction, Hydrogen-related defect, Pollutant degradation","lastPublishedDoi":"10.21203/rs.3.rs-7239099/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7239099/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn photocatalytic degradation of pollutants, hydrogen-related defects on the catalyst surface inhibit the generation of highly reactive hydroxyl radicals (\u0026middot;OH) and superoxide radicals (\u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e). Therefore, strategies to mitigate such defects are crucial for enhancing photocatalytic efficiency. To address this challenge, ZnWO\u003csub\u003e4\u003c/sub\u003e/HRP heterojunction photocatalysts were successfully prepared via a simple hydrothermal method, constructing a compact interfacial structure where rod-shaped ZnWO\u003csub\u003e4\u003c/sub\u003e uniformly attaches to the HRP surface. Photocatalytic performance tests revealed that the composites exhibited excellent catalytic activity for rhodamine B (RhB) degradation, with a rate constant of 0.21 min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e within 15 min \u0026minus;\u0026thinsp;3.5 and 21 times higher than those of individual HRP and ZnWO\u003csub\u003e4\u003c/sub\u003e, respectively. Moreover, due to the robust chemical structure and strong interfacial bonding between ZnWO\u003csub\u003e4\u003c/sub\u003e and HRP, the composite maintains high photocatalytic stability across multiple catalytic cycles. Mechanistic analysis demonstrates that the S-scheme heterojunction effectively suppresses the formation of hydrogen-related defects on the ZnWO\u003csub\u003e4\u003c/sub\u003e surface, significantly reducing surface defect state density. This inhibition enhances photogenerated carrier separation, accelerates charge transfer, and facilitates the efficient generation of \u0026middot;O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e. By adopting a heterojunction strategy to address hydrogen - related defects, the catalyst\u0026rsquo;s visible-light absorption capacity, photoelectric conversion efficiency, and radical generation efficiency were enhanced, while carrier recombination was suppressed. These findings provide new insights for designing high-efficiency heterojunction photocatalysts and highlight their promising potential in photocatalytic removal of organic pollutants.\u003c/p\u003e","manuscriptTitle":"Suppression of hydrogen-related defect in ZnWO 4 /HRP S-scheme heterojunction to enhance internal charge transfer in materials","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-27 15:40:40","doi":"10.21203/rs.3.rs-7239099/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-28T02:16:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-27T11:21:38+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-24T12:58:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"329981576684249091263880921010208437437","date":"2025-08-19T02:38:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"207055724778263191065580482594956866226","date":"2025-08-18T05:54:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"321458961559900980120865511080042701992","date":"2025-08-17T03:42:15+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-17T02:29:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-04T13:53:53+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-04T13:50:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Research on Chemical Intermediates","date":"2025-07-29T04:59:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"research-on-chemical-intermediates","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"rint","sideBox":"Learn more about [Research on Chemical Intermediates](http://link.springer.com/journal/11164)","snPcode":"11164","submissionUrl":"https://submission.nature.com/new-submission/11164/3","title":"Research on Chemical Intermediates","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"981dd105-6883-4181-8a79-e933e1ba74c9","owner":[],"postedDate":"August 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-03T16:06:05+00:00","versionOfRecord":{"articleIdentity":"rs-7239099","link":"https://doi.org/10.1007/s11164-025-05755-6","journal":{"identity":"research-on-chemical-intermediates","isVorOnly":false,"title":"Research on Chemical Intermediates"},"publishedOn":"2025-10-29 15:58:45","publishedOnDateReadable":"October 29th, 2025"},"versionCreatedAt":"2025-08-27 15:40:40","video":"","vorDoi":"10.1007/s11164-025-05755-6","vorDoiUrl":"https://doi.org/10.1007/s11164-025-05755-6","workflowStages":[]},"version":"v1","identity":"rs-7239099","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7239099","identity":"rs-7239099","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}