Enhancement in photocatalytic H2 evolution utilizing the synergistic effect between dual cocatalysts and heterojunctions

Expediting electrons-holes separation and surface reaction kinetics is deemed to be pivotal factor to determine the photocatalytic performance. Decoration of reductive and oxidative cocatalysts on semiconductors is a resultful approach for motivating electrons-holes separation and surface reaction kinetics. In this work, a ternary 2.4%-(CoSe₂@NiS-1)/CdS photocatalyst was developed. Among this compound, reductive cocatalyst CoSe₂ not only acted as electron trapping center by extracting photogenerated electrons, but also constructed Schottky junction with CdS to accelerate migration of photogenerated carriers and inhibit the backflow. Meanwhile, oxidative cocatalyst NiS forming p-n type heterojunction with CdS served as hole-trap center to boost transport and consumption of photoinduced holes. Integrating of dual cocatalysts and heterojunctions played synergistic effect in promoting the photocatalytic performance and photo-corrosion stability. 2.4%-(CoSe₂@NiS-1)/CdS achieved H₂ evolution of 1413.9 μmol and maintained at 85.47% after six cycles. It's expected that this work can provide an insight into designing high active solar energy conversion system.     

Highly efficient Bi2O3/MoS2 p-n heterojunction photocatalyst for H2 evolution from water splitting

The design of p-n heterojunction photocatalysts to overcome the drawbacks of low photocatalytic activity that results from the recombination of charge carriers and narrow photo-response range is promising technique for future energy. Here, we demonstrate the facile hydrothermal synthesis for the preparation of Bi₂O₃/MoS₂ p-n heterojunction photocatalysts with tunable loading amount of Bi₂O₃ (0–15 wt%). The structure, surface morphology, composition and optical properties of heterostructures were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, Brunauer-Emmett-Teller (BET) surface area, photoluminescence (PL), electrochemical impedance spectroscopy (EIS). Compare to pure Bi₂O₃ and MoS_2, the Bi₂O₃/MoS₂ heterostructures displayed significantly superior performance for photocatalytic hydrogen (H₂) production using visible photo-irradiation. The maximum performance for hydrogen evolution was achieved over Bi₂O₃/MoS₂ photocatalyst (10 μmol h⁻¹g⁻¹) with Bi₂O₃ content of 11 wt%, which was approximately ten times higher than pure Bi₂O₃ (1.1 μmol h⁻¹g⁻¹) and MoS₂ (1.2 μmol h⁻¹g⁻¹) photocatalyst. The superior performance was attributed to the robust light harvesting ability, enhanced charge carrier separation via gradual charge transferred pathway. Moreover, the increased efficiency of Bi₂O₃/MoS₂ heterostructure photocatalyst is discussed through proposed mechanism based on observed performance, band gap and band position calculations, PL and EIS data.     

Efficient interfacial charge transfer of 2D/2D CoP/CdS heterojunction for extremely boosted photocatalytic H2 evolution performance

Constructing 2D/2D heterojunction photocatalysts has attracted great attentions due to their inherent advantages such as larger interfacial contact areas, short transfer distance of charges and abundant reaction active sites. Herein, 2D/2D CoP/CdS heterojunctions were successfully fabricated and employed in photocatalytic H₂ evolution using lactic acid as sacrificial reagents. The multiple characteristic techniques were adopted to investigate the crystalline phases, morphologies, optical properties and textual structures of heterojunctions. It was found that integrating 2D CoP nanosheets as cocatalysts with 2D CdS nanosheets by Co–S chemical bonds would significantly boost the photocatalytic H₂ evolution performances, and the 7 wt% 2D/2D CoP/CdS heterojunction possessed the maximal H₂ evolution rate of 92.54 mmol g^?1 h^?1, approximately 31 times higher than that of bare 2D CdS nanosheets. Photoelectrochemical, steady photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements indicated that there existed an effective charge separation and migration over 2D/2D CoP/CdS heterojunction, which then markedly lengthened the photoinduced electrons average lifetimes, retarded the recombination of charge carriers, and caused the dramatically boosted photocatalytic H₂ evolution activity. Moreover, the density functional theory (DFT) calculation further corroborated that the efficient charge transfer occurred at the interfaces of CoP/CdS heterojunction. This present research puts forward a promising strategy to engineer the 2D/2D heterojunction photocatalysts endowed with an appealing photocatalytic H₂ evolution performance.     

Enhanced charge transfer for efficient photocatalytic H2 evolution over UiO-66-NH2 with annealed Ti3C2Tx MXenes

The annealed Ti₃C₂T_x MXenes retained original layered morphology and gave rise to the formation of TiO₂ is anticipated to achieve improved photocatalytic hydrogen evolution performance as a noble-metal-free co-catalyst. In this work, a novel Ti₃C₂/TiO₂/UiO-66-NH₂ hybrid was rationally designed for the first time by simply introducing annealed Ti₃C₂T_x MXenes over water-stable Zr-MOFs (UiO-66-NH₂) precursors via a facile hydrothermal process. As expected, the rationally designed Ti₃C₂/TiO₂/UiO-66-NH₂ displayed significantly improvement in photocatalytic H₂ performance (1980 μmol·h⁻¹·g⁻¹) than pristine UiO-66-NH₂ under simulated sunlight irradiation. The excellent photocatalytic HER activity can be attributed to the formation of multi-interfaces in Ti₃C₂/TiO₂/UiO-66-NH₂, including Ti₃C₂/TiO₂/UiO-66-NH₂, Ti₃C₂/TiO₂ and Ti₃C₂/UiO-66-NH₂ interfaces, which constructed multiple pathways at the interfaces with Schottky junctions to accelerate the separation and transfer of charge carriers and endowed the accumulation of photo-generated electrons on the surface of Ti₃C₂. This work expanded the possibility of porous MOFs for the development of efficient photocatalytic water splitting using annealed MXenes.     

Pt modified TiO2/NiO p-n junction with enhanced surface reaction and charge separation for efficient photocatalytic hydrogen evolution

Efficient charge separation is crucial for solar energy conversion in semiconductor-based systems. Creating p-n junction is an effective strategy to enhance charge separation because the built-in electric field could inhibit charge recombination. However, in many situations, the high reaction barrier will limit the surface reaction rate, resulting in poor carrier utilization of the p-n junction. Here, with carefully designed cocatalyst loading, we successfully overcome the limitation and obtain the full effectiveness of the p-n junction. When used for photocatalytic water splitting, the well-designed catalyst exhibits excellent photocatalytic activity, with a hydrogen evolution rate as high as 13.2 mmol h^?1 g^?1, which is 18 times higher than that of the pristine p-n junction. Further investigation reveals that the enhancement should be attributed to the synergistic effect between cocatalyst and p-n junction, with the cocatalyst improves reaction rate on the surface and the p-n junction accelerates charge separation in the bulk simultaneously. This work provides an effective strategy to modify the surface properties of p-n junction through cocatalysts-loading for efficient photocatalytic hydrogen evolution.     

CoNi bimetallic alloy cocatalyst-modified TiO2 nanoflowers with enhanced photocatalytic hydrogen evolution

In terms of improving photocatalytic hydrogen production performance, inexpensive and earth-rich cocatalysts have become promising alternatives to precious metals. Herein, a novel CoNi–TiO₂ photocatalyst composed of TiO₂ nanoflowers and CoNi alloy was prepared by hydrothermal and chemical reduction methods. Various characterizations and test results have confirmed that the further improvement of the photocatalytic performance of the CoNi–TiO₂ photocatalyst is mainly due to the fact that the bimetallic CoNi alloy can accelerate charge transfer and inhibit the recombination of photo-induced carriers. The hydrogen production rate of the prepared CoNi–TiO₂ is about 24 times higher than that of the pristine TiO₂, and its hydrogen production rate value can reach 6580.9 μmol g^?1 h^?1, and showing comparable photocatalytic performance to 0.5 wt% Pt–TiO₂. In addition, combined with the characterization results, a probable mechanism for enhanced photocatalytic performance was proposed. This study provides favorable enlightenment for the design of a series of highly efficient non-precious metal TiO₂-based photocatalysts.     

Nanoparticle metal Ni cocatalyst on NiTe2 microsphere for improved photocatalytic hydrogen evolution

Scalable and sustainable photocatalytic hydrogen evolution via water splitting requires highly active, stable and earth-abundant cocatalysts to replace rare and expensive metal Platinum. Herein, two facile and similar thermal injection methods are employed to synthesize 3D NiTe₂ microsphere and 0D/3D Ni/NiTe₂ Schottky heterojunction photocatalyst. The optimized 6% Ni/NiTe₂ composite shows good H₂ evolution activity with a rate of 2214.2 μmol g⁻¹·h⁻¹- about 1.55 times higher than that of single NiTe₂. Especially, it is the first time to report that NiTe₂ and Ni/NiTe₂ composite have the activity of producing H₂O₂ through the two-electron reduction of O₂ during photocatalytic water splitting. This enhanced photocatalytic performance can be attributed to the rapid separation and migration of photogenerated charge carriers, low interfacial resistance, abundant surface active sites and two-electron reduction reaction process. This work provides an innovative approach for designing and constructing the potential metal-semiconductor composites with unique electronic structures.     

Based on amorphous carbon C@ZnxCd1-xS/Co3O4 composite for efficient photocatalytic hydrogen evolution

In this work, C@Zn_xCd_1-xS/Co₃O₄ catalyst which with high hydrogen production activity was prepared and the catalyst was characterized by SEM, TEM, XRD, XPS, Uv–vis DRS characterization. After two-step modification, the light absorption intensity of C@Zn_xCd_1-xS and C@Zn_xCd_1-xS/Co₃O₄ showed an increasing trend compared with pure Zn_xCd_1-xS, such phenomenon was beneficial to the visible light absorption and utilization of photocatalyst. In addition, Mott-Schottky proved that Zn_xCd_1-xS catalyst formed p-n heterojunction with Co₃O₄ nanoparticles, which further demonstrated that the modification of Zn_xCd_1-xS by Co₃O₄ was successful. And the hydrogen production of C@Zn_xCd_1-xS/Co₃O₄ (30%) (1405.1 μmol) was 6.9 times that of pure Zn_xCd_1-xS. The improvement of photocatalytic performance can be attributed to that carbon particles accelerate the storage and transfer of electrons, and the formation of p-n heterojunction between Co₃O₄ and Zn_xCd_1-xS promotes the separation of photogenerated carriers effectively. In this study, the introduction of amorphous carbon and Co₃O₄ promoted the transfer and separation of electrons and holes greatly, thereby inhibited the recombination of carriers and provided the favorable conditions for the preparation of highly efficient and stable photocatalysts.     

Construction of noble-metal-free FeWO4/Mn0.5Cd0.5S photocatalyst to optimize H2 evolution performance in water splitting

Designing cost-effective photocatalysts with remarkable performance is a foresighted strategy to foster the evolution of H₂ in water splitting. In this study, a p-n heterojunction FeWO₄/Mn_0.5Cd_0.5S photocatalyst modified by low-cost and non-toxic FeWO₄ was synthesized using hydrothermal and calcination methods. The hydrogen evolution activity of Mn_0.5Cd_0.5S was strengthened by varying the amount of FeWO₄ loading. The hydrogen production rate of FeWO₄/Mn_0.5Cd_0.5S photocatalyst loaded with 10% FeWO₄ can reach 9.63 mmol g^?1 h^?1, which is equivalent to 2.16 times of pure Mn_0.5Cd_0.5S. The enhancement of the H₂ evolution activity was primarily contributed to a p-n heterojunction formed at the interface of FeWO₄ and Mn_0.5Cd_0.5S. It provides a fast pathway for the migration and separation of photogenerated charges and effectively inhibits the photo-corrosion of Mn_0.5Cd_0.5S.     

Amorphous sulfur-rich CoSx nanodots as highly efficient cocatalyst to promote photocatalytic hydrogen evolution over TiO2

In this work, amorphous cobalt sulfide with a sulfur-rich structure (sr-CoS_x) is developed as the cocatalyst for photocatalytic hydrogen evolution. Through a facile hydrothermal reaction, sr-CoS_x nanodots are in situ grown on TiO₂ to obtain a heterojunction photocatalyst (sr-CoS_x/TiO₂). The as-prepared photocatalyst exhibits remarkable improved hydrogen evolution performance compared with TiO₂. Under the irradiation of xenon lamp, the hydrogen evolution rate of sr-CoS_x/TiO₂ can reach 507 μmol h^?1 g^?1, which is about 121 times that of pristine TiO₂, indicating that sr-CoS_x is a highly efficient cocatalyst to promote hydrogen evolution on TiO₂. Moreover, sr-CoS_x/TiO₂ exhibits better performance than crystalline CoS₂ or amorphous CoS modified TiO₂, suggesting the important role of sulfur-rich structure and amorphous state in promoting the cocatalytic effect. Electrochemical and photoluminescence measurements show the most efficient carrier separation between sr-CoS_x and TiO₂, which also contributes to its high photocatalytic hydrogen evolution performance.     

Energy band modulation in CuxP(x=3,1/2)/PbTiO3 via heterogeneous erection induced benign junction interface for enhanced photocatalytic H2 evolution

Prompt recombination of photo-generated charges in semiconducting material strictly restrict photocatalytic process efficiency. Herein, coupling of Cu_xP nanoparticles and PbTiO₃ nanoplates through inert atmosphere calcination process for outstanding H₂ production has been reported. Uniform edging distribution of Cu_xP nanoparticles over PbTiO₃ nanoplates; witnessed from TEM analysis revealed an intimate material contact for charge transportation to the active reaction sites of catalyst surface. Besides, junction interface between Cu_xP and PbTiO₃ component; confirmed from XPS and Mott-Schottky analysis yield an amplified photo/electro-chemical and catalytic performance. A stronger photocurrent density via., H₂O₂ electron scavenger and larger photovoltage in junction material compared with PbTiO₃ counterpart; follows higher surface charge transfer efficiency and slower potential decay with longer charge carriers lifetime simultaneously. The PbTiO₃ nanoplates with an optimum amount of Cu_xP have achieved maximum H₂ production attaining conversion efficiency of 9.72%. Consequently, a type-II energy band alignment mechanism has been proposed for enhanced H₂ production.     

Promoted interfacial charge transfer by coral-like nickel diselenide for enhanced photocatalytic hydrogen evolution over carbon nitride nanosheet

Seeking an efficient and non-precious co-catalyst for g-C₃N₄ (CN) remains a great demanding to achieve high photocatalytic hydrogen generation performance. Herein, a composite photocatalyst with high efficiency was prepared by modifying CN with coral-like NiSe₂. The optimal hydrogen evolution rate of 643.16 μmol g^?1 h^?1 is from NiSe₂/CN-5 under visible light. Superior light absorption and interfacial charge transfer properties including suppressed photogenerated carrier recombination and efficient separation of photogenerated electron-hole pairs have been observed, which account for the enhanced photocatalytic performance of CN.     

1D/2D carbon-doped nanowire/ultra-thin nanosheet g-C3N4 isotype heterojunction for effective and durable photocatalytic H2 evolution

It is still challenging to design effective g-C₃N₄ photocatalysts with high separation efficiency of photo-generated charges and strong visible light absorption. Herein, a simple, template-free and “bottom-up” strategy has been developed to prepare 1D/2D g-C₃N₄ isotype heterojunction composed of carbon-doped nanowires and ultra-thin nanosheets. The ethanediamine (EE) grafted on melamine ensures the growth of 1D g-C₃N₄ nanowires with high carbon doping, and the ultra-thin g-C₃N₄ nanosheets were produced through HCl-assisted hydrothermal strategy. The apparent grain boundary between 2D nanosheets and 1D carbon-doped nanowires manifested the formation of the isotype heterojunction. The built-in electric field provide strong driving force for photogenerated carriers separation. Meanwhile, the doping carbon in g-C₃N₄ nanowires promotes visible light absorption. As a result, the photocatalytic H₂ evolution activity of 1D/2D g-C₃N₄ isotype heterojunction is 8.2 time that of the pristine g-C₃N₄, and an excellent stability is also obtained. This work provides a promising strategy to construct isotype heterojunction with different morphologies for effective photocatalytic H₂ evolution.     

Highly sensitive and stable H2 gas sensor based on p-PdO-n-WO3-heterostructure-homogeneously-dispersing thin film

The film-based gas sensor owning high compatibility with semiconductor device fabrication, plays an important role in the miniaturization and integration of the devices. Here, simple metal organic decomposition method and calcining procedure were used to prepare dense WO₃ thin film with PdO nanoparticles being homogeneously dispersed. After painting the silver paste on its surface as electrodes, the H₂ gas sensor was fabricated. At the optimal operating temperature of 160 °C, with response values (R_a/R_g) of 1.2 & 45.1 and response time of 38 s & 4 s, towards 500 ppb and 100 ppm H₂, respectively, the sensor presents high sensitivity and low detection limit together. It is rare to report the H₂ gas sensor based on dense semiconductor film with such low detection limit. Towards 500 ppb and 100 ppm H₂, it still shows the same response values more than half a year later, which proves its stability. A good linear behaviour between the response and relative humidity is observed too. The chief cause of the better performance of the sensor may be the homogeneous and optimal distribution of the p-type PdO nanoparticles in n-type WO₃ film, which is the character of this structure. In addition, the repeatability of the preparing process is very well too. All the better performances suggest that the H₂ sensor based on this structure has a huge potential in practical application.     

A novel direct Z-scheme heterojunction of CoTiO3/ZnIn2S4 for enhanced photocatalytic H2 evolution activity

The shortage of fossil energy has become a growing global concern. It is particularly important to make full use of the infinite solar energy resources, and transform them into sustainable and clean energy. The development of hydrogen energy has become a feasible solution to solve the energy shortage problem. The preparation of photocatalysts featuring efficient charge transfer channels and high hydrogen production activity provides a pathway for the development of hydrogen energy. In this paper, we report for the first time the direct assembly of 2D ZnIn₂S₄ (ZIS) nanosheets on the surface of CoTiO₃ (CTO). The synthesized CoTiO₃/ZnIn₂S₄ (CTO/ZIS) photocatalyst features a direct Z-scheme charge transfer channel, which enhances the separation rate of photogenerated carriers, and accelerates the photocatalytic H₂ evolution (PHE) rate. Without the assistance of any co-catalyst, the PHE rate of prepared CoTiO₃/ZnIn₂S₄ was as high as 5.21 mmol g^?1 h^?1. Moreover, the H₂ evolution rate of CoTiO₃/ZnIn₂S₄ almost did not decrease significantly after four consecutive 4 h cycles. This investigation provides a valuable approach for the exploitation of novel and efficient Z-scheme photocatalysts in the application of solar energy to hydrogen energy conversion.     

Mn0.2Cd0.8S nanorods assembled with 0D CoWO4 nanoparticles formed p-n heterojunction for efficient photocatalytic hydrogen evolution

In this work, p-type semiconductor CoWO₄ nanoparticles was successfully anchored on the surface of n-type Mn_0.2Cd_0.8S nanorods, and p-n type heterostructure photocatalysts with low cost and high efficiency were synthesized. By optimizing the loading of CoWO₄ nanoparticles, the hydrogen evolution rate of the compound can reach a maximum, the peak is 408 μmol/5 h. Under visible light irradiation, it is equivalent to 3.61 times pure Mn_0.2Cd_0.8S. In addition, the composite catalyst has favorable durability and structural stability. In terms of morphology, the combination of nanorods (S_BET = 24 m²g^-1) and nanoparticles (S_BET = 12 m²g^-1) increased the specific surface area of the composite catalyst (S_BET = 31 m²g^-1), thus the composite exposed more active sites. In terms of heterojunction, the conduction bands of two semiconductors were determined by UV–vis diffuse reflection and Mott-Schottky, and the construction of p-n heterojunction was verified. The results of photochemical experiment further indicate that the built-in electric field in the p-n type heterostructure not only accelerates the electron-hole pair transfer, but vastly enhances the carrier average lifetime. In this paper, the morphology of the photocatalyst was modified and p-n heterojunction was constructed. The result is that the performance of Mn_0.2Cd_0.8S MCS was improved and the possible mechanism of photocatalytic hydrogen evolution was proposed.     

Oxygen vacancy and p-n junction synergistically boosting photocatalytic hydrogen evolution in alkaline solution for a 2D lamellar Co3O4/K7HNb6O19

The exploration of efficient alkaline hydrogen evolution photocatalysts is very meaningful in overall water splitting due to the fact that the high O₂ evolution performance is usually obtained under alkaline conditions. Herein, we successfully prepared a kind of photocatalysts with excellent H₂ production activity in an alkaline environment by combining Lindqvist-type polyoxoniobate K₇HNb₆O₁₉ with Co₃O₄. The hydrogen production performance of the optimal sample could reach 5394.17 μmol g^?1 under highly alkaline conditions. The superior H₂ evolution activity is mainly endowed by p-n heterojunction creating an internal-built electric field on the interface of the two semiconductors, which realizes the effective spatial separation of electron-hole pairs. Simultaneously, the increased oxygen vacancies and lamellar structure of catalysts also respectively endow samples with a high H₂O adsorption capacity and efficient photoinduced carrier separation rate. The work will be instructive for designing high-efficiency and stable HER catalyst in alkaline conditions for practical applications.     

Highly efficient thiomolybdate [Mo2S12]2- nanocluster cocatalyst decorated on TiO2 to boost photocatalytic hydrogen evolution

The exploitation of noble-metal-free photocatalysts with high solar-to-H₂ conversion efficiency is a hot topic in the photocatalysis field. Molybdenum sulfide materials, which have good physicochemical properties and excellent hydrogen evolution activity, have become an effective noble metal cocatalyst substitute and attracted widespread attention. In this work, a highly efficient photocatalyst constructed by decorating thiomolybdate [Mo₂S₁₂]^2- nanoclusters on TiO₂ is reported for the first time. The resultant [Mo₂S₁₂]^2-/TiO₂ photocatalyst shows a remarkable enhanced hydrogen evolution rate under the Xenon light irradiation. At the optimal loading amount of [Mo₂S₁₂]^2-, the photocatalyst exhibits a photocatalytic hydrogen evolution rate of 213.1 μmol h^?1 g^?1, which is about 51 times that of the pure TiO₂. Characterization results show that the intimate contact between [Mo₂S₁₂]^2- and TiO₂ promotes the separation of hole-electron pairs, prolongs the lifetime of carriers, and thereby increases the photocatalytic activity. Furthermore, abundant bridging S in the [Mo₂S₁₂]^2- acts as active sites for hydrogen evolution, which also contributes to the enhanced hydrogen production rate. This work demonstrates an efficient way for the construction of noble-metal-free hydrogen evolution photocatalyst and provides a useful reference for the development of low cost photocatalysts in the future.     

Boosted photogenerated carriers separation in Z-scheme Cu3P/ZnIn2S4 heterojunction photocatalyst for highly efficient H2 evolution under visible light

Developing low-cost, highly efficient and robust photocatalystic hydrogen evolution system is a promising solution to environmental and energy crisis. Herein, a Z-scheme Cu₃P/ZnIn₂S₄ heterojunction photocatalyst was successfully constructed for the first time via a facile solution-phase hybridization method. The optimized Cu₃P/ZIS composite exhibited the highest H₂ production rate of 2561.1 μmol g⁻¹ h⁻¹ under visible light irradiation (>420 nm), which was 5.2 times greater than that of bare ZnIn₂S₄ and even exceeded the photocatalytic performance of Pt/ZIS composite. The apparent quantum yield of 10 wt% Cu₃P/ZnIn₂S₄ can reach 22.3% at 420 nm. The huge boost of photocatalytic hydrogen evolution activity is ascribed to the formation of heterojunction with the built in electric field within Cu₃P/ZnIn₂S₄ and Z-scheme charge carriers transfer pathway, which result in efficient separation and migration of charge carriers. In addition, both experimental and theoretical calculation confirmed that the charge-carriers transfer pathway of Cu₃P/ZnIn₂S₄ photocatalyst follows the Z-scheme mechanism instead of conventional type-Ⅱ heterojunction mechanism. This work is considered helpful for getting a great deal of insight into constructing high-activity and cost-effective transition metal phosphides (TMPs) based photcatalytic hydrogen production system and rationally designing Z-scheme heterojunction photocatalyst.     

Enhanced photocatalytic H2 evolution over In2S3 via decoration with GO and Fe2P co-catalysts

In this study, GO and Fe₂P were used as co-catalysts to improve the separation efficiency of photogenerated electron-hole pairs in an In₂S₃ photocatalyst. The metallic character of Fe₂P provided a cheap substitute for traditional noble metal co-catalyst for H₂ production in aqueous media. The GO/Fe₂P/In₂S₃ composite demonstrated significantly enhanced photocatalytic activity compared to pure In₂S₃, delivering a H₂ production rate of 483.35 μmol h^?1 g^?1 and a quantum yield was 22.68% under visible light irradiation. The design of the photocatalyst was optimized using “Design Expert” software. The analysis showed that a GO loading of 1.18 wt%, a Fe loading of 5.36 wt%, and a calcination temperature of 180 °C were optimal.