Highly efficient TiO 2 –graphene nanocomposite for methylene blue decomposition under visible-light irradiation

Highly efficient TiO 2 –graphene nanocomposite for methylene blue decomposition under visible-light irradiation | 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 Highly efficient TiO 2 –graphene nanocomposite for methylene blue decomposition under visible-light irradiation Reza Naderzadeh, Masoud Vesali-Naseh, Majid Rezaeivala This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6944176/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Nov, 2025 Read the published version in Research on Chemical Intermediates → Version 1 posted 11 You are reading this latest preprint version Abstract Methylene blue (MB) as a persistent dye poses serious environmental threats, requiring efficient removal methods. In the present study, the TiO 2 -graphene nanocomposites have been fabricated for MB d ecomposition under visible-light irradiation. The graphene oxide (GO) was synthesized using the modified Hummers method and was doped on the pure TiO 2 with different amounts of 5-75 wt.% using hydrothermal method. The obtained nanocomposites were characterized using the FTIR, SEM, TEM, BET, XRD, and PL techniques. The photocatalytic activity of TiO 2 -reduced graphene composites for the oxidation of MB is relatively higher than those of pure TiO 2 . The nanocomposite containing the optimal 50% reduced GO exhibits the highest catalytic activity, achieving nearly complete degradation in less than 10 minutes. The incorporation of oxygen-functionalized reduced graphene oxide into mixed-phase TiO₂ (comprising both anatase and rutile) enhances the adsorption surface area, reduces the band gap, and suppresses electron-hole recombination. The kinetic of MB degradation was described by the pseudo-first-order model with a high-rate constant. Photocatalytic degradation TiO2 Graphene oxide Visible light Methylene blue Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Dyes are organic compounds that exist in both natural and synthetic forms and are extensively utilized across various industries, including textile processing, plastic manufacturing, paper production, and cosmetics [1]. As a significant category of environmental pollutants, dyes primarily enter aquatic ecosystems through industrial wastewater effluents, posing serious ecological risks [2]. To treat wastewater contaminated with dyes, several approaches can be employed, including physical methods (such as adsorption, membrane filtration, and ion exchange) [3], chemical methods (including photolysis, electrochemical treatments, and coagulation-flocculation) [4], advanced oxidation processes (like photo-fenton, sonocatalysis, and ozonation) [5], as well as biological methods that utilize bacteria, enzymes, and algae [6]. Hybrid approaches, such as adsorption-membrane systems, filtration-activated sludge processes, and membrane bioreactor-photocatalytic membranes, can also be employed [7]. The photocatalytic process utilizing TiO 2 is a well-established technique not only for the removal of dyes but also for the elimination of heavy metals [8], desulfurization [9], solar cell [10], and simultaneous electricity generation [11]. TiO 2 has emerged as a highly regarded photoactive material due to its low cost, environmental friendliness, and excellent photocatalytic oxidation properties [12]. However, the high band gap of crystalline TiO 2 (3.0–3.2 eV) leads to rapid recombination of photogenerated electron-hole pairs, which hinders its efficient utilization for visible-light applications [13]. Key factors influencing photocatalytic activity include specific surface area, phase composition, carbon content, and crystallite size [14]. To reduce the band gap and extend the absorbance into the visible-light region, TiO 2 can be modified through doping techniques. This can be achieved by combining TiO 2 with various materials, including metals [15], metal oxides [16], nonmetals [17], mesoporous materials [18], polymers [19], and carbon-based materials such as carbon nanotubes [20] and graphene (oxide) [21]. Graphene (oxide) has become a prominent material for modification due to its high surface area, superior charge carrier mobility, and excellent thermal conductivity [22]. Incorporating graphene into TiO 2 hybrids can enhance surface area, quantum properties, and crystallite size, leading to increased adsorption capacity for dyes and improved photocatalytic reaction rates of TiO 2 in aqueous solutions [23]. Additionally, graphene sheets can function as visible-light absorbers or electron sinks, enhancing electron-hole separation and thereby suppressing the recombination process [21]. Furthermore, the presence of oxygen-containing functional groups on the surface of graphene sheets significantly improves the chemical reactivity and adsorption capacity for metals and inorganic precursors [24]. In this study, MB, a significant azo dye, was degraded in aqueous solution through a photocatalytic reaction under visible-light irradiation. The photocatalyst was synthesized via a hydrothermal method using TiO 2 , graphene oxide (GO), and an ethanol-water solution as the solvent. The effect of different quantities of GO incorporated into the TiO 2 structure on photocatalytic activity was evaluated. Experimental 2.1. Materials The mixed-phase TiO 2 (98 wt.%) and graphite powder (99 wt.%) were obtained from COSMO Chemical and Merc Company, respectively. All other chemicals used were of analytical grade and sourced from Ghatran Shimi Company. Deionized water was utilized for the preparation of aqueous solutions. 2.2. Preparation of GO GO was synthesized from graphite powder using chemical oxidation via a modified Hummers method (Fig. 1). In this process, 3 g of graphite powder was mixed with 18 g of KMnO 4 and added to a solution of 360 ml H 2 SO 4 and 40 ml H 3 PO 4 . The mixture was stirred at 50 °C for 24 hours. Once the solution changed to a dark green colour, 400 ml of distilled water was gradually added while stirring gently. Next, 3.0 ml of H 2 O 2 was slowly added until the colour shifted to yellow-orange. After 72 hours, the precipitate was collected and decanted from the acidic solution until the pH reached approximately 6. Finally, the washed precipitate was dried at 80 °C for 24 hours, resulting in the collection of brownish GO powder. To prepare reduced graphene oxide (RGO), 1.0 g of GO was mixed with 50 ml of ethanol and 25 ml of deionized water, then stirred for 2 hours at room temperature. The mixture was transferred to an autoclave and heated at 150 °C for 5 hours. The resulting precipitate was then dried at 80 °C for 24 hours to obtain black RGO. 2.3. Preparation of TiO 2 –graphene photocatalyst The TiO 2 –graphene photocatalysts (TGP) with varying GO content (5, 10, 25, 50, and 75 wt.%) were synthesized using an in-situ hydrothermal method. First, 1.0 g of TiO 2 and the corresponding amount of GO were dispersed in a mixture of 50 ml of deionized water and 25 ml of ethanol, and the mixture was vigorously stirred for 8 hours at room temperature. Next, the homogeneous suspension was transferred to a Teflon-lined steel autoclave reactor and maintained at 170 °C for 8 hours. After the reaction, the resultant sample was separated, washed several times with deionized water using a decanter, and dried at 80 °C overnight (Fig. 1). The samples with 5, 10, 25, 50, and 75 wt.% GO content were designated as TGP-5, TGP-10, TGP-25, TGP-50, and TGP-75, respectively. 2.4. Photocatalytic activity The photocatalytic activity of the TGP samples was evaluated by measuring the degradation of MB using a homemade setup under visible-light irradiation (Fig. 1). A 100 W GLS light bulb was used to generate visible light (λ = 400 nm). For the MB degradation process, 10 mg of TGP was added to 100 ml of a MB solution (5 mg/L) in a quartz beaker, which was stirred using a magnetic stirrer. The beaker was placed inside a cylindrical chamber with a shiny aluminium coating to reflect light. One side of the cylinder was open to allow light to enter, and it was positioned 40 cm away from the lamp (Fig. 1). The reaction suspension was irradiated for 60 minutes, and 3 ml samples were taken at 10-minute intervals. The suspension samples were centrifuged to separate the TGP, and the remaining solution was analysed to determine the MB concentration. This analysis was conducted using a UV-2450 Shimadzu ultraviolet-visible spectrophotometer, measuring absorption intensity at the maximum characteristic wavelength of 663 nm. All experimental data represent the average values from triplicate experiments. 2.5. Characterization The surface characterization and morphology of TiO 2 and TGP samples were analysed using scanning electron microscopy (SEM, Seron AIS2300C) and transmission electron microscopy (TEM, Philips EM 208S). X-ray diffraction (XRD, APD2000 Pro) and Fourier-transform infrared spectroscopy (FTIR, Shimadzu IRPrestige-2) were employed to determine the structural features and functional groups of the samples. The electron transfer properties and band gap energy of the different samples were assessed using photoluminescence (PL) emission measurements at room temperature within the range of 250–600 nm, along with Tauc plots. Additionally, the Brunauer-Emmett-Teller (BET) method and Barrett Joyner–Halenda (BJH) equation were used to calculate specific surface area and pore size distribution of the samples using nitrogen adsorption-desorption branch at 77 K, with pore volume assessed at a relative pressure of p/p ₀ = 0.99. Results and discussion 3.1. Characterization of the photocatalysts 3.1.1. Physical description Fig. 2 illustrates the colour change of TGP composites with varying graphene content before and after the hydrothermal process. The addition of black RGO results in a darker TGP solution compared to the lighter brown of GO. 3.1.2. FTIR results Fig. 3a shows the FTIR spectra of GO and RGO samples. The GO exhibits a broad peak around 3390 cm -1 , attributed to the typical –OH stretching bond [24]. This peak's intensity significantly decreases upon conversion from GO to RGO, indicating the elimination of oxygenated functional groups during the hydrothermal process [25]. Additionally, two relatively sharp peaks at 1735 cm -1 and 1624 cm -1 correspond to the vibration of the carbonyl (C═O) bond and the skeletal vibration of the aromatic C=C bond in the GO structure. A broad peak at 1080 cm -1 is associated with the stretching vibration of the C–O bond [24]. In Fig. 3b , theFTIR spectra of TGP composites reveal a characteristic peak at 671 cm -1 , which is related to the vibration of Ti–O–Ti bonds [20]. Furthermore, the absorption peaks associated with oxygen-containing groups are significantly weakened, confirming the preferential anchoring of graphene to TiO 2 [21, 25]. 3.1.3. XRD results The XRD patterns of graphite, GO, and RGO samples are presented in Fig. 4a. In comparison to the sharp peak of graphite around 2θ = 27°, GO exhibits a distinct sharp diffraction peak at 2θ = 9.5°, which is attributed to the (001) plane [13, 26]. This sharp peak in GO is replaced by a broad peak at 2θ = 25° in the RGO sample, corresponding to the (002) plane [12]. The broad peak in RGO indicates a reduction in the structural order compared to the original graphite. Fig. 4b displays the XRD pattern of TiO 2 hybrids with varying graphene content. The peaks associated with the TiO 2 content correspond to the anatase and rutile phases. Specifically, the peaks at 25.3°, 36.1°, 47.8°, 56.6°, 62.6°, 70.2°, and 74.9° are attributed to the anatase phase of TiO 2 , corresponding to the (101), (004), (200), (211), (204), (220), and (215) planes, in accordance with ICDD file (no. 03‐065‐5714). Additionally, the peaks at 27.4°, 37.7°, 41.5°, 54.3°, 64.4°, and 68.7° are assigned to the rutile phase of TiO 2 , corresponding to the (110), (200), (111), (211), (310), and (301) planes, based on ICDD file (no. 04‐008‐7850). The weight fraction of the anatase phase (W A ) was calculated to be approximately 44% using the following equation [27]: W A = I A / [I A +1.265 I R ] (1) Where I R and I A represent the peak intensities of the rutile (110) plane and the anatase (101) plane, respectively. It is well-known that the anatase phase exhibits superior photocatalytic activity compared to the rutile phase [5]. However, in this work, the mixed-phase TiO 2 , when combined with graphene sheets, demonstrates high photocatalytic activity. This enhancement is attributed to the rutile phase's ability to reduce the recombination rate of photoexcited electrons and holes [14]. As the graphene content in the TiO 2 hybrid increases, the peak intensities generally decrease, except for the peak around 25°, which overlaps with the characteristic peak of RGO. However, the similar peak positions in the XRD patterns of both bare TiO 2 and the TGP samples indicate that RGO does not introduce new pathways for crystal phase growth. Additionally, the disappearance of the peak corresponding to GO in the TGP samples suggests that GO has been converted to RGO [12]. 3.1.4. SEM, TEM and E DX results The SEM and TEM image of TGP-50 sample are presented in Fig. 5. The TiO 2 exhibits an irregular spherical morphology with an average size of 145 nm while the GO content exhibits a lamellar structure with wrinkled layers. The TGP-50 sample demonstrates a random distribution of TiO 2 grains anchored to the surface of the graphene sheets, which is a result of the hydrothermal process. This anchoring helps prevent TiO 2 aggregation and graphene stacking, leading to an enhancement in photocatalytic activity [25]. Additionally, the EDX spectrum confirms the presence of carbon (58.29%) and oxygen (41.71%) in the GO sample (Fig. S1a). In contrast, the TGP-50 sample (Fig.S1b) contains carbon (58.29%), oxygen (41.71%), and titanium (18.08%). 3.1.5. Adsorption–desorption results The nitrogen adsorption-desorption isotherm and the average pore size for different samples are presented in Fig. S2. According to the IUPAC classification, the TGP-50 sample shows a mesoporous structure with H3 type hysteresis loop of type IV isotherm [28]. Compared to bare TiO 2 , which has a BET surface area of 13.54 m²/g and a pore volume of 0.044 cm³/g, the TGP-50 exhibits higher values of 21.55 m²/g for surface area and 0.064 cm³/g for pore volume. The increased surface area of TGP-50 provides a greater number of active sites for MB adsorption, potentially enhancing its photocatalytic activity [14]. 3.1.6. PL and DRS analysis The PL analysis was conducted to investigate the charge separation of the photocatalyst. The PL spectrum of bare TiO 2 displayed multiple peaks at approximately 416, 478, and 535 nm, with the emission intensities diminishing upon the addition of graphene (Fig. 6a). This PL quenching indicates a significant suppression of the recombination rate of electron-hole pairs, which is attributed to the transfer of photo-generated electrons from the conduction band of TiO 2 to the graphene sheets [29]. According to the Tauc plots (Fig. 6b), TGP-50 has a lower band gap (approximately 2.8 eV) compared to bare TiO₂, which has a band gap of 3.1 eV. This could indicate graphene-induced mid-gap states, doping, or interfacial interactions that narrow the effective band gap of TiO 2 and enabling visible-light activity [13]. 3.2. Photocatalytic activity for MB degradation Fig. 7 illustrates the colour change of the MB solution when treated with bare TiO 2 and TGP composites under visible-light radiation at 5-minute intervals. The bare TiO 2 exhibits no significant photocatalytic activity for MB degradation. In contrast, increasing the graphene content from 5 to 75 wt.% enhances the photocatalytic activity of the nanocomposites. Notably, the TGP-50 composite results in a colourless solution after approximately 10 minutes, confirming the complete degradation of MB. Fig. 8 presents the concentration change of the MB solution during the photocatalytic reaction with bare TiO 2 and different TGP composites under visible-light radiation. Degradation increases with irradiation time, plateauing as MB is depleted or intermediates accumulate. The photocatalytic performance, based on MB degradation, is defined by the following conversion rate (R) equation: Where C₀ represents the initial concentration of MB, and Cₜ indicates the concentration of MB in the solution (mg/L) at time t. The bare TiO 2 demonstrates less than 20% conversion over a 25-minute period due to poor visible-light activity and recombination. However, the addition of 5-50 wt. % graphene to TiO 2 increases the conversion rate, with the TGP-50 sample achieving complete MB degradation in just 10 minutes. Further addition of RGO decreases the conversion rate to 85% after 25 minutes. The excess graphene may block active sites on TiO₂ or reduce light penetration, slightly lowering efficiency. The enhanced photocatalytic activity of the TGP samples can be attributed to the presence of graphene, which contributes to band gap narrowing and a reduction in the recombination rate of photo-generated electron-hole pairs. The pseudo-first-order kinetic of MB degradation in aqueous solution was investigated using the Eq. 3. This model explores the relationship between the degradation rate (r MB ) and MB concentration at time t based on the following equation: where C 0 and C represent the initial and final concentrations of MB, respectively. The k a values were determined from the linear plot of ln (C 0 /C) versus time (Fig. 8b). Deviations from linearity might suggest competing processes such as adsorption-desorption equilibrium. The k a values are 0.087, 0.073, 0.037, 0.013, and 0.007 for TGP-25, TGP-75, TGP-10, TGP-5, and bare TiO 2 , respectively. The k a increases with graphene content, reflecting enhanced charge separation and light absorption. In the case of TGP-50, since the reaction was completed quickly within 10 minutes, the rate constant was not calculated. Notably, all TGP samples exhibit significantly higher k a values compared to bare TiO 2 , which aligns with the observed colour change in Fig. 7 and confirms their superior photocatalytic activity. To further elucidate graphene’s role in enhancing this activity, the following mechanisms are proposed: TiO 2 -RGO + h𝝊 → TiO 2 -RGO (h + + e - ) (5) TiO 2 -RGO (h + + e - ) → TiO 2 (h + )-RGO (e - ) (6) RGO (e - ) + O 2 (ads) → RGO + (7) TiO 2 (h + ) + H 2 O → TiO 2 + OH + H + (8) Due to its narrow bandgap, the TGP sample can be excited under visible-light irradiation, facilitating electron transfer to the conduction band of TiO 2 . The photoexcited electrons subsequently migrate to the graphene surface, promoting efficient charge separation and suppressing electron-hole recombination [ 25]. The photogenerated electrons and holes (Eqs. 5 and 6) are scavenged by adsorbed oxygen and water molecules, yielding reactive oxygen species (Eqs. 7 and 8). These reactive species then facilitate the oxidative degradation of MB via redox reactions [ 22, 30]. While the presence of RGO enhances the photocatalytic activity of TGP, excessive amounts of graphene (greater than 50 wt.%) may hinder light absorption [31]. Additionally, higher graphene content can increase the distance that electrons must travel to reach the MB molecules, thereby raising the likelihood of recombination. Table 1 summarizes the performance of various TiO 2 -graphene nanocomposites for MB removal. Compared to other studies, the TGP-50 sample demonstrates significant MB degradation with a rapid reaction time. Table 1 Comparison of TGP-50 performance with other photocatalysts for MB degradation. Photocatalyst sample Photocatalyst dosage (g/L) MB conc. (mg/L) Degradation efficiency (%) Reaction time (min) Ref. TiO 2 /GO 1.5 20 90 420 [32] TiO 2 /GO 0.8 10 95.5 60 [33] TiO 2 /RGO 0.1 5 90 160 [34] TiO 2 /RGO 0.5 10 91.5 60 [14] TiO 2 /20 % GO 0.08 10 98.8 100 [1] TiO 2 /50 % RGO 0.1 5 99.9 10 present work Conclusion The hydrothermal process is an efficient method for synthesizing TiO 2 -graphene nanocomposites. The combination of mixed-phase TiO 2 with graphene sheets, which have a high surface area and low band gap, results in an effective photocatalyst under visible light. The optimal graphene content (50 wt.%) maximizes MB degradation by balancing charge separation, light absorption, and surface area. Graphene increases adsorption sites for MB, acts as an electron sink, reducing recombination rate and extends light absorption into the visible range. Excess graphene (> 50%) might reduce efficiency due to light shielding or agglomeration. Hence, graphene-based TiO 2 composites can be effective photocatalysts for dye degradation under visible light. 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Supplementary Files supplemantry.docx Cite Share Download PDF Status: Published Journal Publication published 03 Nov, 2025 Read the published version in Research on Chemical Intermediates → Version 1 posted Editorial decision: Revision requested 27 Aug, 2025 Reviews received at journal 21 Aug, 2025 Reviewers agreed at journal 14 Aug, 2025 Reviewers agreed at journal 07 Aug, 2025 Reviews received at journal 05 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers agreed at journal 22 Jul, 2025 Reviewers invited by journal 22 Jul, 2025 Editor assigned by journal 24 Jun, 2025 Submission checks completed at journal 24 Jun, 2025 First submitted to journal 21 Jun, 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. 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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-6944176","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":488963616,"identity":"f2b0a04e-19de-46cf-91e9-d0b0bfcfe71b","order_by":0,"name":"Reza Naderzadeh","email":"","orcid":"","institution":"Hamedan University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Reza","middleName":"","lastName":"Naderzadeh","suffix":""},{"id":488963618,"identity":"debb17d4-ea99-433a-b322-344df20fcf91","order_by":1,"name":"Masoud Vesali-Naseh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8UlEQVRIiWNgGAWjYBACgwMgkg3MZjyQUHEAJo5biyWSFoYDCWcOMPAQ0mKPooWxDaYFDzA7fvzhgw9lDIn9/IcfHHg4707ifgbmhx8YCu7h1nImx9hwxjmGxJkz0gwOJG57ltjDwGYswWBQjFvLgRw2ad42BmODGwwgLYeBWhjMgH5JwKnF4PzzZ2At9uePfziQOAekhf0bfi03EsxAWuQMGHKAtjSAtPAQsOXGG5BfJOQkbuQUHEg4dti45zBPsUQCXoelg0LMhoe///jGhz9qDsu2t7dv/PDhD24tUCCBxGYGYoIaRsEoGAWjYBTgBQB5VFmJPe8tpgAAAABJRU5ErkJggg==","orcid":"","institution":"Hamedan University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Masoud","middleName":"","lastName":"Vesali-Naseh","suffix":""},{"id":488963619,"identity":"9dbfd7d0-2b38-4c4e-b268-e22633734eeb","order_by":2,"name":"Majid Rezaeivala","email":"","orcid":"","institution":"Hamedan University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Majid","middleName":"","lastName":"Rezaeivala","suffix":""}],"badges":[],"createdAt":"2025-06-21 09:53:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6944176/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6944176/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11164-025-05799-8","type":"published","date":"2025-11-03T15:57:36+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":87528150,"identity":"c6c4d49f-ffc1-4cd7-aee6-f960455e151c","added_by":"auto","created_at":"2025-07-24 20:22:57","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":166227,"visible":true,"origin":"","legend":"\u003cp\u003eThe scheme of TGP synthesis process and its application in dye removal.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/d537fe643d6b935638b2ac03.png"},{"id":87527352,"identity":"72c0b904-4088-4896-b6d2-a40fd8f74abd","added_by":"auto","created_at":"2025-07-24 19:58:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":251758,"visible":true,"origin":"","legend":"\u003cp\u003eThe colour change of TGP composites with different graphene content (a) before and (b) after hydrothermal process.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/c51694c2175a08ee99b56ae8.png"},{"id":87527715,"identity":"8aea4e07-8670-4350-8d0c-4a8ad784a93f","added_by":"auto","created_at":"2025-07-24 20:06:57","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":75381,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of (a) GO and RGO, and (b) various TGP composites.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/db4d15551e88b6a22e1b5a09.png"},{"id":87527999,"identity":"1c9687eb-913f-47a5-ad12-17b9b0848c16","added_by":"auto","created_at":"2025-07-24 20:14:57","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":106149,"visible":true,"origin":"","legend":"\u003cp\u003eXRD pattern of (a) graphite, GO, and RGO, (b) various TGP samples.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/22027ce3f56ef4f59d4ef48b.png"},{"id":87528530,"identity":"ffa3f735-4875-4e39-ab83-79d057acfd27","added_by":"auto","created_at":"2025-07-24 20:30:57","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":157148,"visible":true,"origin":"","legend":"\u003cp\u003e(a) SEM and (b) TEM image of TGP-50 sample.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/56a714601ce5ab308813cde5.png"},{"id":87527356,"identity":"1465a1ee-67bf-4495-8791-756b11ab95e9","added_by":"auto","created_at":"2025-07-24 19:58:57","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":39302,"visible":true,"origin":"","legend":"\u003cp\u003e(a) PL spectra and (b) Tauc plot of TiO\u003csub\u003e2\u003c/sub\u003e and TGP-50 samples.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/1f98f3eb2e5577237a91d824.png"},{"id":87527364,"identity":"8ed95808-ccbc-478e-bd04-7d542766081f","added_by":"auto","created_at":"2025-07-24 19:58:57","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":300144,"visible":true,"origin":"","legend":"\u003cp\u003eThe colour change of MB solution during the photocatalytic process under visible light using (a) bare TiO\u003csub\u003e2\u003c/sub\u003e, (b)TGP-5, (c) TGP-10, (d)TGP-25, (e) TGP-50, and (f) TGP-75. Samples were collected at 5-minute intervals.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/7f8160f98bec36705fdaa5c7.png"},{"id":87527372,"identity":"f0628bcd-ea64-4385-815f-d54529a0b8eb","added_by":"auto","created_at":"2025-07-24 19:58:57","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":54511,"visible":true,"origin":"","legend":"\u003cp\u003e(a)The effect of graphene content on MB decomposition under visible-light radiation in aqueous solution and (b) The pseudo-first-order kinetic model for different samples.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/f2ac8ff58c295c29aac3e9ac.png"},{"id":95564049,"identity":"335f6cc5-5743-42a1-98d4-0a559f70b2dd","added_by":"auto","created_at":"2025-11-10 16:07:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1888795,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/db356436-3955-4af7-9162-4d8e46cb6df4.pdf"},{"id":87527717,"identity":"ece3ccbc-3b2e-4262-be54-a23c4b52933c","added_by":"auto","created_at":"2025-07-24 20:06:57","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":140384,"visible":true,"origin":"","legend":"","description":"","filename":"supplemantry.docx","url":"https://assets-eu.researchsquare.com/files/rs-6944176/v1/abb18c639dc2b46b042cffb8.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Highly efficient TiO 2 –graphene nanocomposite for methylene blue decomposition under visible-light irradiation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDyes are organic compounds that exist in both natural and synthetic forms and are extensively utilized across various industries, including textile processing, plastic manufacturing, paper production, and cosmetics [1]. As a significant category of environmental pollutants, dyes primarily enter aquatic ecosystems through industrial wastewater effluents, posing serious ecological risks [2]. To treat wastewater contaminated with dyes, several approaches can be employed, including physical methods (such as adsorption, membrane filtration, and ion exchange) [3], chemical methods (including photolysis, electrochemical treatments, and coagulation-flocculation) [4], advanced oxidation processes (like photo-fenton, sonocatalysis, and ozonation) [5], as well as biological methods that utilize bacteria, enzymes, and algae [6]. Hybrid approaches, such as adsorption-membrane systems, filtration-activated sludge processes, and membrane bioreactor-photocatalytic membranes, can also be employed [7]. \u003c/p\u003e\n\u003cp\u003eThe photocatalytic process utilizing TiO\u003csub\u003e2\u003c/sub\u003e is a well-established technique not only for the removal of dyes but also for the elimination of heavy metals [8], desulfurization [9], solar cell [10], and simultaneous electricity generation [11].\u003c/p\u003e\n\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e has emerged as a highly regarded photoactive material due to its low cost, environmental friendliness, and excellent photocatalytic oxidation properties [12]. However, the high band gap of crystalline TiO\u003csub\u003e2\u003c/sub\u003e (3.0\u0026ndash;3.2 eV) leads to rapid recombination of photogenerated electron-hole pairs, which hinders its efficient utilization for visible-light applications [13]. Key factors influencing photocatalytic activity include specific surface area, phase composition, carbon content, and crystallite size [14].\u003cspan dir=\"RTL\"\u003e \u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eTo reduce the band gap and extend the absorbance into the visible-light region, TiO\u003csub\u003e2\u003c/sub\u003e can be modified through doping techniques. This can be achieved by combining TiO\u003csub\u003e2\u003c/sub\u003e with various materials, including metals [15], metal oxides [16], nonmetals [17], mesoporous materials [18], polymers [19], and carbon-based materials such as carbon nanotubes [20] and graphene (oxide) [21]. \u003c/p\u003e\n\u003cp\u003eGraphene (oxide) has become a prominent material for modification due to its high surface area, superior charge carrier mobility, and excellent thermal conductivity [22]. Incorporating graphene into TiO\u003csub\u003e2\u003c/sub\u003e hybrids can enhance surface area, quantum properties, and crystallite size, leading to increased adsorption capacity for dyes and improved photocatalytic reaction rates of TiO\u003csub\u003e2\u003c/sub\u003e in aqueous solutions [23]. Additionally, graphene sheets can function as visible-light absorbers or electron sinks, enhancing electron-hole separation and thereby suppressing the recombination process [21]. Furthermore, the presence of oxygen-containing functional groups on the surface of graphene sheets significantly improves the chemical reactivity and adsorption capacity for metals and inorganic precursors [24].\u003c/p\u003e\n\u003cp\u003eIn this study, MB, a significant azo dye, was degraded in aqueous solution through a photocatalytic reaction under visible-light irradiation. The photocatalyst was synthesized via a hydrothermal method using TiO\u003csub\u003e2\u003c/sub\u003e, graphene oxide (GO), and an ethanol-water solution as the solvent. The effect of different quantities of GO incorporated into the TiO\u003csub\u003e2\u003c/sub\u003e structure on photocatalytic activity was evaluated.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cp\u003e\u003cstrong\u003e2.1. Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe mixed-phase TiO\u003csub\u003e2\u003c/sub\u003e (98 wt.%) and graphite powder (99 wt.%) were obtained from COSMO Chemical and Merc Company, respectively. All other chemicals used were of analytical grade and sourced from Ghatran Shimi Company. Deionized water was utilized for the preparation of aqueous solutions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Preparation of GO\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGO was synthesized from graphite powder using chemical oxidation via a modified Hummers method (Fig. 1). In this process, 3 g of graphite powder was mixed with 18 g of KMnO\u003csub\u003e4\u003c/sub\u003e and added to a solution of 360 ml H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e and 40 ml H\u003csub\u003e3\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e. The mixture was stirred at 50 \u0026deg;C for 24 hours. Once the solution changed to a dark green colour, 400 ml of distilled water was gradually added while stirring gently. Next, 3.0 ml of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was slowly added until the colour shifted to yellow-orange. After 72 hours, the precipitate was collected and decanted from the acidic solution until the pH reached approximately 6. Finally, the washed precipitate was dried at 80 \u0026deg;C for 24 hours, resulting in the collection of brownish GO powder.\u003c/p\u003e\n\u003cp\u003eTo prepare reduced graphene oxide (RGO), 1.0 g of GO was mixed with 50 ml of ethanol and 25 ml of deionized water, then stirred for 2 hours at room temperature. The mixture was transferred to an autoclave and heated at 150 \u0026deg;C for 5 hours. The resulting precipitate was then dried at 80 \u0026deg;C for 24 hours to obtain black RGO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Preparation of TiO\u003csub\u003e2\u003c/sub\u003e\u0026ndash;graphene photocatalyst\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe TiO\u003csub\u003e2\u003c/sub\u003e\u0026ndash;graphene photocatalysts (TGP) with varying GO content (5, 10, 25, 50, and 75 wt.%) were synthesized using an in-situ hydrothermal method.\u003c/p\u003e\n\u003cp\u003eFirst, 1.0 g of TiO\u003csub\u003e2\u003c/sub\u003e and the corresponding amount of GO were dispersed in a mixture of 50 ml of deionized water and 25 ml of ethanol, and the mixture was vigorously stirred for 8 hours at room temperature. Next, the homogeneous suspension was transferred to a Teflon-lined steel autoclave reactor and maintained at 170 \u0026deg;C for 8 hours.\u003c/p\u003e\n\u003cp\u003eAfter the reaction, the resultant sample was separated, washed several times with deionized water using a decanter, and dried at 80 \u0026deg;C overnight (Fig. 1). The samples with 5, 10, 25, 50, and 75 wt.% GO content were designated as TGP-5, TGP-10, TGP-25, TGP-50, and TGP-75, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. Photocatalytic activity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe photocatalytic activity of the TGP samples was evaluated by measuring the degradation of MB using a homemade setup under visible-light irradiation (Fig. 1). A 100 W GLS light bulb was used to generate visible light (\u0026lambda; = 400 nm).\u003c/p\u003e\n\u003cp\u003eFor the MB degradation process, 10 mg of TGP was added to 100 ml of a MB solution (5 mg/L) in a quartz beaker, which was stirred using a magnetic stirrer. The beaker was placed inside a cylindrical chamber with a shiny aluminium coating to reflect light. One side of the cylinder was open to allow light to enter, and it was positioned 40 cm away from the lamp (Fig. 1).\u003c/p\u003e\n\u003cp\u003eThe reaction suspension was irradiated for 60 minutes, and 3 ml samples were taken at 10-minute intervals. The suspension samples were centrifuged to separate the TGP, and the remaining solution was analysed to determine the MB concentration. This analysis was conducted using a UV-2450 Shimadzu ultraviolet-visible spectrophotometer, measuring absorption intensity at the maximum characteristic wavelength of 663 nm. All experimental data represent the average values from triplicate experiments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5. Characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe surface characterization and morphology of TiO\u003csub\u003e2\u003c/sub\u003e and TGP samples were analysed using scanning electron microscopy (SEM, Seron AIS2300C) and transmission electron microscopy (TEM, Philips EM 208S). X-ray diffraction (XRD, APD2000 Pro) and Fourier-transform infrared spectroscopy (FTIR, Shimadzu IRPrestige-2) were employed to determine the structural features and functional groups of the samples.\u003c/p\u003e\n\u003cp\u003eThe electron transfer properties and band gap energy of the different samples were assessed using photoluminescence (PL) emission measurements at room temperature within the range of 250\u0026ndash;600 nm, along with Tauc plots. Additionally, the Brunauer-Emmett-Teller (BET) method and Barrett Joyner\u0026ndash;Halenda (BJH) equation were used to calculate specific surface area and pore size distribution of the samples using nitrogen adsorption-desorption branch at 77 K, with pore volume assessed at a relative pressure of p/p\u003csub\u003e₀\u003c/sub\u003e = 0.99.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003e\u003cstrong\u003e3.1. Characterization of the photocatalysts\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.1. Physical description\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFig. 2\u003c/strong\u003eillustrates the colour change of TGP composites with varying graphene content before and after the hydrothermal process. The addition of black RGO results in a darker TGP solution compared to the lighter brown of GO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.2. FTIR results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFig. 3a\u003c/strong\u003eshows the FTIR spectra of GO and RGO samples. The GO exhibits a broad peak around 3390 cm\u003csup\u003e-1\u003c/sup\u003e, attributed to the typical \u0026ndash;OH stretching bond [24]. This peak\u0026apos;s intensity significantly decreases upon conversion from GO to RGO, indicating the elimination of oxygenated functional groups during the hydrothermal process [25]. Additionally, two relatively sharp peaks at 1735 cm\u003csup\u003e-1\u0026nbsp;\u003c/sup\u003eand 1624 cm\u003csup\u003e-1\u003c/sup\u003e correspond to the vibration of the carbonyl (C═O) bond and the skeletal vibration of the aromatic C=C bond in the GO structure. A broad peak at 1080 cm\u003csup\u003e-1\u0026nbsp;\u003c/sup\u003eis associated with the stretching vibration of the C\u0026ndash;O bond [24].\u003c/p\u003e\n\u003cp\u003eIn \u003cstrong\u003eFig. 3b\u003c/strong\u003e\u003cstrong\u003e,\u0026nbsp;\u003c/strong\u003etheFTIR spectra of TGP composites reveal a characteristic peak at 671 cm\u003csup\u003e-1\u003c/sup\u003e, which is related to the vibration of Ti\u0026ndash;O\u0026ndash;Ti bonds [20]. Furthermore, the absorption peaks associated with oxygen-containing groups are significantly weakened, confirming the preferential anchoring of graphene to TiO\u003csub\u003e2\u003c/sub\u003e [21, 25].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.3. XRD results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD patterns of graphite, GO, and RGO samples are presented in Fig. 4a. In comparison to the sharp peak of graphite around 2\u0026theta; = 27\u0026deg;, GO exhibits a distinct sharp diffraction peak at 2\u0026theta; = 9.5\u0026deg;, which is attributed to the (001) plane [13, 26]. This sharp peak in GO is replaced by a broad peak at 2\u0026theta; = 25\u0026deg; in the RGO sample, corresponding to the (002) plane [12]. The broad peak in RGO indicates a reduction in the structural order compared to the original graphite.\u003c/p\u003e\n\u003cp\u003eFig. 4b displays the XRD pattern of TiO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ehybrids with varying graphene content. The peaks associated with the TiO\u003csub\u003e2\u003c/sub\u003e content correspond to the anatase and rutile phases. Specifically, the peaks at 25.3\u0026deg;, 36.1\u0026deg;, 47.8\u0026deg;, 56.6\u0026deg;, 62.6\u0026deg;, 70.2\u0026deg;, and 74.9\u0026deg; are attributed to the anatase phase of TiO\u003csub\u003e2\u003c/sub\u003e, corresponding to the (101), (004), (200), (211), (204), (220), and (215) planes, in accordance with ICDD file (no. 03‐065‐5714). Additionally, the peaks at 27.4\u0026deg;, 37.7\u0026deg;, 41.5\u0026deg;, 54.3\u0026deg;, 64.4\u0026deg;, and 68.7\u0026deg; are assigned to the rutile phase of TiO\u003csub\u003e2\u003c/sub\u003e, corresponding to the (110), (200), (111), (211), (310), and (301) planes, based on ICDD file (no. 04‐008‐7850). The weight fraction of the anatase phase (W\u003csub\u003eA\u003c/sub\u003e) was calculated to be approximately 44% using the following equation [27]:\u003c/p\u003e\n\u003cp\u003eW\u003csub\u003eA\u003c/sub\u003e= I\u003csub\u003eA\u003c/sub\u003e / [I\u003csub\u003eA\u003c/sub\u003e +1.265 I\u003csub\u003eR\u003c/sub\u003e] (1)\u003c/p\u003e\n\u003cp\u003eWhere \u003cem\u003eI\u003csub\u003eR\u003c/sub\u003e\u003c/em\u003e and I\u003csub\u003eA\u003c/sub\u003e represent the peak intensities of the rutile (110) plane and the anatase (101) plane, respectively. It is well-known that the anatase phase exhibits superior photocatalytic activity compared to the rutile phase [5]. However, in this work, the mixed-phase TiO\u003csub\u003e2\u003c/sub\u003e, when combined with graphene sheets, demonstrates high photocatalytic activity. This enhancement is attributed to the rutile phase\u0026apos;s ability to reduce the recombination rate of photoexcited electrons and holes [14].\u003c/p\u003e\n\u003cp\u003eAs the graphene content in the TiO\u003csub\u003e2\u003c/sub\u003e hybrid increases, the peak intensities generally decrease, except for the peak around 25\u0026deg;, which overlaps with the characteristic peak of RGO. However, the similar peak positions in the XRD patterns of both bare TiO\u003csub\u003e2\u003c/sub\u003e and the TGP samples indicate that RGO does not introduce new pathways for crystal phase growth. Additionally, the disappearance of the peak corresponding to GO in the TGP samples suggests that GO has been converted to RGO [12].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.4. SEM, TEM and E\u003c/strong\u003e\u003cstrong\u003eDX results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe SEM and TEM image of TGP-50 sample are presented in Fig. 5. The TiO\u003csub\u003e2\u003c/sub\u003e exhibits an irregular spherical morphology with an average size of 145 nm while the GO content exhibits a lamellar structure with wrinkled layers. The TGP-50 sample demonstrates a random distribution of TiO\u003csub\u003e2\u003c/sub\u003e grains anchored to the surface of the graphene sheets, which is a result of the hydrothermal process. This anchoring helps prevent TiO\u003csub\u003e2\u003c/sub\u003e aggregation and graphene stacking, leading to an enhancement in photocatalytic activity [25].\u003c/p\u003e\n\u003cp\u003eAdditionally, the EDX spectrum confirms the presence of carbon (58.29%) and oxygen (41.71%) in the GO sample (Fig. S1a). In contrast, the TGP-50 sample (Fig.S1b) contains carbon (58.29%), oxygen (41.71%), and titanium (18.08%).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.5. Adsorption\u0026ndash;desorption results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe nitrogen adsorption-desorption isotherm and the average pore size for different samples are presented in Fig. S2. According to the IUPAC classification, the TGP-50 sample shows a mesoporous structure\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003ewith H3 type hysteresis loop of type IV isotherm [28]. Compared to bare TiO\u003csub\u003e2\u003c/sub\u003e, which has a BET surface area of 13.54 m\u0026sup2;/g and a pore volume of 0.044 cm\u0026sup3;/g, the TGP-50 exhibits higher values of 21.55 m\u0026sup2;/g for surface area and 0.064 cm\u0026sup3;/g for pore volume. The increased surface area of TGP-50 provides a greater number of active sites for MB adsorption, potentially enhancing its photocatalytic activity [14].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.6. PL and DRS analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe PL analysis was conducted to investigate the charge separation of the photocatalyst. The PL spectrum of bare TiO\u003csub\u003e2\u003c/sub\u003e displayed multiple peaks at approximately 416, 478, and 535 nm, with the emission intensities diminishing upon the addition of graphene (Fig. 6a). This PL quenching indicates a significant suppression of the recombination rate of electron-hole pairs, which is attributed to the transfer of photo-generated electrons from the conduction band of TiO\u003csub\u003e2\u003c/sub\u003e to the graphene sheets [29]. According to the Tauc plots\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e(Fig. 6b), TGP-50 has a lower band gap (approximately 2.8 eV) compared to bare TiO₂, which has a band gap of 3.1 eV.\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003eThis could indicate graphene-induced mid-gap states, doping, or interfacial interactions that narrow the effective band gap of TiO\u003csub\u003e2\u003c/sub\u003e and enabling visible-light activity [13].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Photocatalytic activity for MB degradation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFig. 7 illustrates the colour change of the MB solution when treated with bare TiO\u003csub\u003e2\u003c/sub\u003e and TGP composites under visible-light radiation at 5-minute intervals. The bare TiO\u003csub\u003e2\u003c/sub\u003e exhibits no significant photocatalytic activity for MB degradation. In contrast, increasing the graphene content from 5 to 75 wt.% enhances the photocatalytic activity of the nanocomposites. Notably, the TGP-50 composite results in a colourless solution after approximately 10 minutes, confirming the complete degradation of MB.\u003c/p\u003e\n\u003cp\u003eFig. 8 presents the concentration change of the MB solution during the photocatalytic reaction with bare TiO\u003csub\u003e2\u003c/sub\u003e and different TGP composites under visible-light radiation. Degradation increases with irradiation time, plateauing as MB is depleted or intermediates accumulate. The photocatalytic performance, based on MB degradation, is defined by the following conversion rate (R) equation:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/p\u003e\n\u003cp\u003eWhere C₀ represents the initial concentration of MB, and Cₜ indicates the concentration of MB in the solution (mg/L) at time t. The bare\u0026nbsp;TiO\u003csub\u003e2\u003c/sub\u003e demonstrates less than 20% conversion over a 25-minute period due to poor visible-light activity and recombination. However, the addition of 5-50 wt.\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e% graphene to\u0026nbsp;TiO\u003csub\u003e2\u003c/sub\u003e increases the conversion rate, with the TGP-50 sample achieving complete MB degradation in just 10 minutes. Further addition of RGO\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003edecreases the conversion rate to 85% after 25 minutes. The excess graphene may block active sites on TiO₂ or reduce light penetration, slightly lowering efficiency. The enhanced photocatalytic activity of the TGP samples can be attributed to the presence of graphene, which contributes to band gap narrowing and a reduction in the recombination rate of photo-generated electron-hole pairs.\u003c/p\u003e\n\u003cp\u003eThe pseudo-first-order kinetic of MB degradation in aqueous solution was investigated using the Eq. 3. This model explores the relationship between the degradation rate (r\u003csub\u003eMB\u003c/sub\u003e) and MB concentration at time t based on the following equation:\u003c/p\u003e\n\u003cp\u003e\u003cimg 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\"\u003e\u003c/p\u003e\n\u003cp\u003ewhere C\u003csub\u003e0\u003c/sub\u003e and C represent the initial and final concentrations of MB, respectively. The k\u003csub\u003ea\u003c/sub\u003e values were determined from the linear plot of ln (C\u003csub\u003e0\u003c/sub\u003e/C) versus time (Fig. 8b). Deviations from linearity might suggest competing processes such as adsorption-desorption equilibrium. The k\u003csub\u003ea\u003c/sub\u003e values are 0.087, 0.073, 0.037, 0.013, and 0.007 for TGP-25, TGP-75, TGP-10, TGP-5, and bare\u0026nbsp;TiO\u003csub\u003e2\u003c/sub\u003e, respectively. The k\u003csub\u003ea\u003c/sub\u003e increases with graphene content, reflecting enhanced charge separation and light absorption. In the case of TGP-50, since the reaction was completed quickly within 10 minutes, the rate constant was not calculated. Notably, all TGP samples exhibit significantly higher k\u003csub\u003ea\u003c/sub\u003e values compared to bare\u0026nbsp;TiO\u003csub\u003e2\u003c/sub\u003e, which aligns with the observed colour change in Fig. 7 and confirms their superior photocatalytic activity. To further elucidate graphene\u0026rsquo;s role in enhancing this activity, the following mechanisms are proposed: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e-RGO + h𝝊\u0026nbsp;\u0026rarr; TiO\u003csub\u003e2\u003c/sub\u003e-RGO (h\u003csup\u003e+\u003c/sup\u003e + e\u003csup\u003e-\u003c/sup\u003e) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (5)\u003c/p\u003e\n\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e-RGO (h\u003csup\u003e+\u003c/sup\u003e + e\u003csup\u003e-\u003c/sup\u003e) \u0026rarr; TiO\u003csub\u003e2\u003c/sub\u003e (h\u003csup\u003e+\u003c/sup\u003e)-RGO (e\u003csup\u003e-\u003c/sup\u003e) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (6)\u003c/p\u003e\n\u003cp\u003eRGO (e\u003csup\u003e-\u003c/sup\u003e) + O\u003csub\u003e2\u003c/sub\u003e(ads) \u0026rarr; RGO + \u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (7)\u003c/p\u003e\n\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e (h\u003csup\u003e+\u003c/sup\u003e) + H\u003csub\u003e2\u003c/sub\u003eO \u0026rarr; TiO\u003csub\u003e2\u003c/sub\u003e +\u0026nbsp; OH\u0026nbsp;+ H\u003csup\u003e+ \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/sup\u003e(8)\u003c/p\u003e\n\u003cp\u003eDue to its narrow bandgap, the TGP sample can be excited under visible-light irradiation, facilitating electron transfer to the conduction band of TiO\u003csub\u003e2\u003c/sub\u003e. The photoexcited electrons subsequently migrate to the graphene surface, promoting efficient charge separation and suppressing electron-hole recombination\u003cspan dir=\"RTL\"\u003e\u0026nbsp;[\u003c/span\u003e25].\u003c/p\u003e\n\u003cp\u003eThe photogenerated electrons and holes (Eqs. 5 and 6) are scavenged by adsorbed oxygen and water molecules, yielding reactive oxygen species (Eqs. 7 and 8). These reactive species then facilitate the oxidative degradation of MB via redox reactions\u003cspan dir=\"RTL\"\u003e\u0026nbsp;[\u003c/span\u003e22, 30].\u003c/p\u003e\n\u003cp\u003eWhile the presence of RGO enhances the photocatalytic activity of TGP, excessive amounts of graphene (greater than 50 wt.%) may hinder light absorption [31]. Additionally, higher graphene content can increase the distance that electrons must travel to reach the MB molecules, thereby raising the likelihood of recombination.\u003c/p\u003e\n\u003cp\u003eTable 1 summarizes the performance of various TiO\u003csub\u003e2\u003c/sub\u003e-graphene nanocomposites for MB removal. Compared to other studies, the TGP-50 sample demonstrates significant MB degradation with a rapid reaction time.\u003c/p\u003e\n\u003cp\u003eTable 1 Comparison of TGP-50 performance with other photocatalysts for MB degradation.\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"643\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 126px;\"\u003e\n \u003cp\u003ePhotocatalyst\u003c/p\u003e\n \u003cp\u003esample\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003ePhotocatalyst dosage (g/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eMB conc. (mg/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eDegradation efficiency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003eReaction time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003eRef.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/GO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e420\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e[32]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/GO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e95.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e[33]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/RGO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e[34]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/RGO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e91.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e[14]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/20 % GO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e98.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e[1]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e/50 % RGO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e99.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003epresent work\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe hydrothermal process is an efficient method for synthesizing TiO\u003csub\u003e2\u003c/sub\u003e-graphene nanocomposites. The combination of mixed-phase TiO\u003csub\u003e2\u003c/sub\u003e with graphene sheets, which have a high surface area and low band gap, results in an effective photocatalyst under visible light. The optimal graphene content (50 wt.%) maximizes MB degradation by balancing charge separation, light absorption, and surface area. Graphene increases adsorption sites for MB, acts as an electron sink, reducing recombination rate and extends light absorption into the visible range. Excess graphene (\u0026gt; 50%) might reduce efficiency due to light shielding or agglomeration. Hence, graphene-based TiO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ecomposites can be effective photocatalysts for dye degradation under visible light.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\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.\u003c/p\u003e\n\u003cp\u003eAuthor Contribution\u003c/p\u003e\n\u003cp\u003eNaderzadeh has done the experiments. Vesali-Naseh wrote the main manuscript text and Rezaeivala has reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003eData Availability\u003c/p\u003e\n\u003cp\u003eData is provided within the manuscript and supplementary files.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eRong X, Qiu F, Zhang C, Fu L, Wang Y, Yang D. Preparation, characterization and photocatalytic application of TiO2\u0026ndash;graphene photocatalyst under visible light irradiation. 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Novel titanium dioxide\u0026ndash;graphene\u0026ndash;activated carbon ternary nanocomposites with enhanced photocatalytic performance in rhodamine B and tetracycline hydrochloride degradation. Journal of Materials Science. 2017;52:8311-20.\u003c/li\u003e\n \u003cli\u003eShahbazi R, Payan A, Fattahi M. Preparation, evaluations and operating conditions optimization of nano TiO2 over graphene based materials as the photocatalyst for degradation of phenol. Journal of Photochemistry and Photobiology A: Chemistry. 2018;364:564-76.\u003c/li\u003e\n \u003cli\u003eMengting Z, Kurniawan TA, Fei S, Ouyang T, Othman MHD, Rezakazemi M, et al. Applicability of BaTiO3/graphene oxide (GO) composite for enhanced photodegradation of methylene blue (MB) in synthetic wastewater under UV\u0026ndash;vis irradiation. Environmental pollution. 2019;255:113182.\u003c/li\u003e\n \u003cli\u003eTayel A, Ramadan AR, El Seoud OA. Titanium dioxide/graphene and titanium dioxide/graphene oxide nanocomposites: Synthesis, characterization and photocatalytic applications for water decontamination. Catalysts. 2018;8(11):491.\u003c/li\u003e\n \u003cli\u003eCong Y, Long M, Cui Z, Li X, Dong Z, Yuan G, et al. Anchoring a uniform TiO2 layer on graphene oxide sheets as an efficient visible light photocatalyst. Applied Surface Science. 2013;282:400-7.\u003c/li\u003e\n \u003cli\u003eNguyen-Phan T-D, Pham VH, Shin EW, Pham H-D, Kim S, Chung JS, et al. The role of graphene oxide content on the adsorption-enhanced photocatalysis of titanium dioxide/graphene oxide composites. Chemical Engineering Journal. 2011;170(1):226-32.\u003c/li\u003e\n \u003cli\u003eTorabi Momen M, Piri F, Karimian R. Photocatalytic degradation of rhodamine B and methylene blue by electrochemically prepared nano titanium dioxide/reduced graphene oxide/poly (methyl methacrylate) nanocomposite. Reaction Kinetics, Mechanisms and Catalysis. 2020;129(2):1145-57.\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":"Photocatalytic degradation, TiO2, Graphene oxide, Visible light, Methylene blue","lastPublishedDoi":"10.21203/rs.3.rs-6944176/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6944176/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMethylene blue (MB) as a persistent dye poses serious environmental threats, requiring efficient removal methods. In the present study, the TiO\u003csub\u003e2\u003c/sub\u003e-graphene nanocomposites have been fabricated for MB \u003cu\u003ed\u003c/u\u003eecomposition under visible-light irradiation. The graphene oxide (GO) was synthesized using the modified Hummers method and was doped on the pure TiO\u003csub\u003e2\u003c/sub\u003e with different amounts of 5-75 wt.% using hydrothermal method.\u003c/p\u003e\n\u003cp\u003eThe obtained nanocomposites were characterized using the FTIR, SEM, TEM, BET, XRD, and PL techniques. The photocatalytic activity of TiO\u003csub\u003e2\u003c/sub\u003e-reduced graphene composites for the oxidation of MB is relatively higher than those of pure TiO\u003csub\u003e2\u003c/sub\u003e. The nanocomposite containing the optimal 50% reduced GO exhibits the highest catalytic activity, achieving nearly complete degradation in less than 10 minutes.\u003c/p\u003e\n\u003cp\u003eThe incorporation of oxygen-functionalized reduced graphene oxide into mixed-phase TiO₂ (comprising both anatase and rutile) enhances the adsorption surface area, reduces the band gap, and suppresses electron-hole recombination. The kinetic of MB degradation was described by the pseudo-first-order model with a high-rate constant.\u003c/p\u003e","manuscriptTitle":"Highly efficient TiO 2 –graphene nanocomposite for methylene blue decomposition under visible-light irradiation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-24 19:58:53","doi":"10.21203/rs.3.rs-6944176/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-27T08:04:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-21T16:41:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"97505842280844884404141295284673408139","date":"2025-08-14T15:04:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"84238927064273086991513868872289082335","date":"2025-08-07T11:41:17+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-06T00:05:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"176899005749314221164655111169734071978","date":"2025-08-04T00:01:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"240033006060164847237352166631121886714","date":"2025-07-22T06:29:41+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-22T06:19:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-24T14:17:15+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-24T14:16:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Research on Chemical Intermediates","date":"2025-06-21T09:48:39+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":"fe29fc38-00ce-45f3-b75c-77091ae23c10","owner":[],"postedDate":"July 24th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-10T16:01:37+00:00","versionOfRecord":{"articleIdentity":"rs-6944176","link":"https://doi.org/10.1007/s11164-025-05799-8","journal":{"identity":"research-on-chemical-intermediates","isVorOnly":false,"title":"Research on Chemical Intermediates"},"publishedOn":"2025-11-03 15:57:36","publishedOnDateReadable":"November 3rd, 2025"},"versionCreatedAt":"2025-07-24 19:58:53","video":"","vorDoi":"10.1007/s11164-025-05799-8","vorDoiUrl":"https://doi.org/10.1007/s11164-025-05799-8","workflowStages":[]},"version":"v1","identity":"rs-6944176","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6944176","identity":"rs-6944176","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}