Photocurrent and hydrogen production by overall water splitting based on polymeric composite Calix[n]arene/Cyanin Dye/IrO2 nanoparticle

In this study, a new photoelectrochemical cell based on overall splitting of water into oxygen and hydrogen is constructed to obtain an improved photocurrent under a visible range of light. The photoanode was obtained by a gold electrode (GE) modified with carboxylic acid functionalized SH-Calix-4-arene-COOH and IrO₂ nanoparticles attached light absorbing cyanine dye via polymeric oligoaniline linkages. The conductive polymer, 4- (4H-Dithieno [3,2-b: 2 ′, 3′-d] pyrrol-4-yl)aniline, was coated on GE using electropolymerization and used as a photocathode after platinum nanoparticles (Pt) were attached on the surface. The system was illuminated under the visible light, and the water was oxidized via IrO₂ catalyst to produce hydrogen on the photocathode side while oxygen on the photoanode. A photocurrent density of 182.03 μA cm⁻² was obtained by direct transfer of electrons without using a mediator. The bilirubin oxidase (BOx) enzyme was successfully used to remove excess oxygen from the reaction chamber and a further increase in photocurrent was reached up to 272.44 μA cm⁻². Hydrogen production in the reaction chamber was measured by gas chromatography at different time intervals and a maximum of 1.25 × 10⁻⁸ mol cm⁻² was obtained.     

Photoelectrochemical water splitting by engineered multilayer TiO2/GQDs photoanode with cascade charge transfer structure

Herein, for the first time, an efficient photoanode engineered with the cascade structure of FTO|c-TiO₂|few graphene layers|TiO₂/GQDs|Ni(OH)₂ assembly (Ni(OH)₂ photoanode) is designed. This photoanode exhibited much lower electron–hole recombination, fast charge transport, higher visible light harvesting, and excellent performance with respect to FTO|c-TiO₂|TiO₂ assembly (TiO₂ photoanode) in the photoelectrocatalytic oxygen evolution process. The photocurrent density of Ni(OH)₂ photoanode is 7 times (0.35 mA cm⁻² at 1.23 V vs. RHE) greater than that of TiO₂ photoanode (0.045 mA cm⁻² at 1.23 V vs. RHE). The compact TiO₂ (c-TiO₂) layer in Ni(OH)₂ photoanode plays a role of an effective hole-blocking layer. Few-layer graphene layer could speed up the transport of the photogenerated electrons from the conduction band of the TiO₂/GQDs to FTO. Ni(OH)₂ layer could transfer rapidly holes into electrolyte solution.     

Synthesis of reduced graphene oxide–TiO2 nanoparticle composite systems and its application in hydrogen production

The utilization of solar energy for the conversion of water to hydrogen and oxygen has been considered to be an efficient strategy to solve crisis of energy and environment. Here, we report the synthesis of reduced graphene oxide–TiO₂ nanoparticle composite system through the photocatalytic reduction of graphite oxide using TiO₂ nanoparticles. Photoelectrochemical characterizations and hydrogen evolution measurements of these nanocomposites reveal that the presence of graphene enhances the photocurrent density and hydrogen generation rate. The optimum photocurrent density and hydrogen generation rate has been found to be 3.4 mA cm⁻² and 127.5 μmole cm⁻²h⁻¹ in 0.5 M Na₂SO₄ electrolyte solution under 1.5AM solar irradiance of white light with illumination intensity of 100 mW cm⁻². In graphene–TiO₂ nanocomposite, photogenerated electrons in TiO₂ are scavenged by graphene sheets and percolate to counter electrode to reduce H⁺ to molecular hydrogen thus increasing the performance of water-splitting reaction.     

An efficient tandem photoelectrochemical cell composed of FeOOH/TiO2/BiVO4 and Cu2O for self-driven solar water splitting

An integrated solar water splitting tandem cell without external bias was designed using a FeOOH modified TiO₂/BiVO₄ photoanode as a photoanode and p-Cu₂O as a photocathode in this study. An apparent photocurrent (0.37 mA/cm² at operating voltage of +0.36 V_RHE) for the tandem cell without applied bias was measured, which is corresponding to a photoconversion efficiency of 0.46%. Besides, the photocurrent of FeOOH modified TiO₂/BiVO₄–Cu₂O is much higher than the operating point given by pure BiVO₄ and Cu₂O photocathode (∼0.07 mA/cm² at +0.42 V_RHE). Then we established a FeOOH modified TiO₂/BiVO₄–Cu₂O two-electrode system and measured the current density-voltage curves under AM 1.5G illumination. The unassisted photocurrent density is 0.12 mA/cm⁻² and the corresponding amounts of hydrogen and oxygen evolved by the tandem PEC cell without bias are 2.36 μmol/cm² and 1.09 μmol/cm² after testing for 2.5 h. The photoelectrochemical (PEC) properties of the FeOOH modified TiO₂/BiVO₄ photoanode were further studied to demonstrate the electrons transport process of solar water splitting. This aspect provides a fundamental challenge to establish an unbiased and stabilized photoelectrochemical (PEC) solar water splitting tandem cell with higher solar-to-hydrogen efficiency.     

Hierarchical mesoporous SnO2/BiVO4 photoanode decorated with Ag nanorods for efficient photoelectrochemical water splitting

Bismuth vanadate has been extensively investigated as a potential visible light photoanode for PEC water splitting. The performance of BiVO₄ is restricted by fast charge recombination and slow oxygen evolution reaction kinetic. To address these issues, hierarchical SnO₂ (HSN) mesoporous support is developed via a novel sol-electrophoretic approach, and BiVO₄ film is decorated with silver nanorods (Ag NRs). The photocurrent density of HSN/BiVO₄ photoanode is 3.98 mA/cm² at 1.23 V vs. reversible hydrogen electrode (RHE) and onset potential (V_onset) of 0.5 V vs. RHE. The PEC performance is attributed to the appropriate band alignment between SnO₂ and BiVO₄, as well as the hierarchical structure of SnO₂. Ag-HSN/BiVO₄ photoanode shows photocurrent density of 4.30 mA/cm² at 1.23 V vs. RHE and V_onset of 0.28 V vs. RHE. The enhanced photocurrent and negatively shifted V_onset can be attributed to radiative localized surface plasmon resonance decay and catalytic effect of Ag NRs, respectively.     

Fabrication of platinum coated nanoporous gold film electrode: A nanostructured ultra low-platinum loading electrocatalyst for hydrogen evolution reaction

The electrolytic hydrogen evolution reaction (HER) on platinum coated nanoporous gold film (PtNPGF) electrode is demonstrated. The deposition of platinum occurred as a spontaneous redox process in which a copper layer, obtained by underpotential deposition, was oxidized by platinum ions, which were reduced and simultaneously deposited. The present method could provide a very low Pt-loading electrode and the results demonstrated that ultra thin Pt coating effected efficiently and behaved as the nanostructured Pt for electrocatalytic hydrogen evolution reaction. The loading of Pt was calculated as 4.2 × 10⁻³ μg cm⁻² for PtNPGF electrode. The current density at −0.4 V and −0.8 V vs. Ag/AgCl was as high as 0.66 A μg⁻¹ Pt and 3 A μg⁻¹ Pt, respectively and the j₀ was evaluated as 0.03 mA cm⁻² or 8 mA μg⁻¹ Pt. The results indicated that increasing electrode area had no catalytic effect, but the nanostructure nature of as-fabricated electrode and submonolayer deposition of copper resulted in electrocatalytic activity for PtNPGF electrode.     

Self-organized TiO2 nanotube arrays with uniform platinum nanoparticles for highly efficient water splitting

Highly efficient water splitting electrode based on uniform platinum (Pt) nanoparticles on self-organized TiO₂ nanotube arrays (TNTAs) was prepared by a combination of multi-step electrochemical anodization with facile photoreduction process. Uniform platinum (Pt) nanoparticles with an average diameter of 8 nm are distributed homogeneously on nanoporous top layer and underneath TiO₂ nanotube wall. In comparison to pristine TNTAs, Pt@TNTAs show substantially enhanced photocurrent density and the incident photon-to-current conversion efficiency (IPCE) in the entire wavelength window. The maximum photocurrent density and IPCE from the optimized Pt@TNTAs photoelectrode (Pt, ～1.57 wt%) were about 24.2 mA cm⁻² and 87.9% at 350 nm, which is much higher than that of the pure nanotubes sample (16.3 mA cm⁻² and 67.3%). The resultant Pt@TNTAs architecture exhibited significantly enhanced photoelectrochemical activities for solar water splitting with hydrogen evolution rate up to 495 μmol h⁻¹ cm⁻² in 2 M Na₂CO₃ + 0.5 M ethylene glycol under the optimal external bias of −0.3 V_SCE.     

Fabrication of large area nanorod like structured CdS photoanode for solar H2 generation using spray pyrolysis technique

Large area nanorod like structured CdS films (9 × 9 cm²) were deposited on the FTO glass substrate using simple and economic spray pyrolysis deposition technique for photoelectrochemical (PEC) hydrogen production. With an intention of electrode scaling-up, the deposition area of photoanode was varied to evaluate its effect on the PEC hydrogen generation capability. High photocurrent of 5 mA has been achieved from the PEC active area of 37.5 cm². Its unit area (1 cm²) counterpart yielded Solar-to-Hydrogen (STH) conversion efficiency of 0.20% at a bias of 0.2 V vs Ag/AgCl using sacrificial reagents under solar simulator (AM1.5) with 80 mW/cm² irradiance. The 500 nm thick film exhibiting uniformly distributed nano-rod features yielded 3-times more photocurrent, as well as hydrogen evolution than other films. It exhibited an enhanced photo-activity as indicated by the higher IPCE values (5–9%) in the wavelength range of 450–550 nm. It exhibited superior optical properties (E_g ∼2.4 eV), and formation of high crystallinity hexagonal CdS phase with space group P63MC. The superior performance of the photoanode is attributed to the nanostructured morphology acquired under optimized spray pyrolysis conditions. Large area photoanodes showed unaltered photo-activity indicating the homogeneity in the film properties even in scaled-up version.     

Ultrathin hematite films deposited layer-by-layer on a TiO2 underlayer for efficient water splitting under visible light

Ultrathin hematite (α-Fe₂O₃) film deposited on a TiO₂ underlayer as a photoanode for photoelectrochemical water splitting was described. The TiO₂ underlayer was coated on conductive fluorine-doped tin oxide (FTO) glass by spin coating. The hematite films were formed layer-by-layer by repeating the separated two-phase hydrolysis-solvothermal reaction of iron(III) acetylacetonate and aqueous ammonia. A photocurrent density of 0.683 mA cm⁻² at +1.5 V vs. RHE (reversible hydrogen electrode) was obtained under visible light (>420 nm, 100 mW cm⁻²) illumination. The TiO₂ underlayer plays an important role in the formation of hematite film, acting as an intermediary to alleviate the dead layer effect and as a support of large surface areas to coat greater amounts of Fe₂O₃. The as-prepared photoanodes are notably stable and highly efficient for photoelectrochemical water splitting under visible light. This study provides a facile synthesis process for the controlled production of highly active ultrathin hematite film and a simple route for photocurrent enhancement using several photoanodes in tandem.     

A novel visible-light responsive photocatalytic fuel cell with a highly efficient BiVO4/WO3 inverse opal photoanode and a MnO2/graphene oxide nanocomposite modified cathode

A highly efficient inverse-opal structured BiVO₄/WO₃ photoanode and a MnO₂/graphene oxide (GO) nanocomposite modified cathode were successfully synthesized in this paper. The optimized BiVO₄/WO₃ inverse opal photoanode achieved a photocurrent density of ∼5.04 mA/cm² at 1.2 V vs. Ag/AgCl under simulated AM 1.5 illumination, which was 2.84 and 2.36 times higher than that of WO₃ inverse opal photoanode and BiVO₄/WO₃ nanoflake photoanode, respectively. The BiVO₄/WO₃ inverse opal photoanode was coupled with the MnO₂/GO modified cathode to build up a novel visible-light responsive photocatalytic fuel cell (PFC) system. The as-established PFC showed outstanding power production performances in comparison with the PFC equipped with a bare MnO₂ modified cathode. For example, in the former PFC system, the maximum power density and the short circuit current density were ∼66.2 μW/cm² and ∼593.5 μA/cm², respectively, for comparison, in the latter PFC, the values were ∼30.1 μW/cm² and ∼255.9 μA/cm², respectively. The degradation experiment for Rhodamine B confirmed successful application of the as-established PFC in pollutant degradation. The mechanism for the significantly enhanced photoelectrocatalytic performances of the PFC was elucidated. The PFC system presented in this paper opened up a new prototype in developing highly efficient devices for energy conversion and environmental protection.     

Facile fabrication of visible light driven tin oxide photoanode and its photoelectrochemical water splitting properties

Photoelectrochemical water splitting is a promise way to transfer solar energy to hydrogen as chemical energy carrier. In this paper, visible light driven tin oxide based photoelectrodes were obtained through dipping SnCl₂·2H₂O EtOH solution on FTO or metal Ti substrate and with further heat treatment process. Photoelectrochemical measurements with three electrodes configuration revealed that this obtained photoelectrode showed n-type responsive properties and the photocurrent density reached mA/cm² level without any modification under visible light irradiation (λ > 420 nm). XRD, UV–Vis spectrum and control experimental results proposed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn⁴⁺/Sn²⁺ transformation and surface oxygen deficiency, and the tin oxide can be denoted as SnO_2−x.     

Microwave-assisted low temperature fabrication of nanostructured α-Fe2O3 electrodes for solar-driven hydrogen generation

It is demonstrated for the first time that significant enhancement of photoelectrochemical performance could be achieved by using microwave-assisted annealing for the fabrication of α-Fe₂O₃ thin films. The process can also lead to significant energy savings (>60% when compared with conventional methods). Different types of Fe thin films were oxidized using both microwave and conventional heating techniques. The photoelectrochemical performance of electrodeposited, undoped and Si-doped iron oxide samples showed that microwave-annealing resulted in superior structural and performance enhancements. The photocurrent densities obtained from microwave annealed samples are among the highest values reported for α-Fe₂O₃ photoelectrodes fabricated at low temperatures and short times; the highest photocurrent density at 0.55 V vs. V_Ag/AgCl, before the dark current onset, was 450 μA cm⁻² for the Si-doped films annealed at 270 °C for 15 min using microwave irradiation (and 180 μA cm⁻² at 0.23 V vs. V_Ag/AgCl) while conventional annealing at the same temperature resulted in samples with negligible (3 μA cm⁻²) photoactivity. In contrast, a 450 °C/15 min conventional heat treatment only resulted in a film with 25% lower photocurrent density than that of the microwave annealed sample. The improved performance is attributed to the lower processing temperatures and rapidity of the microwave method that help to retain the nanostructure of the thin films whilst restricting the grain growth to a minimum. The lower processing temperature requirements of the microwave process can also open up the possibility of fabricating hematite thin films on conducting, flexible, plastic electronic substrates.     

In2O3:Sn/TiO2/CdS heterojunction nanowire array photoanode in photoelectrochemical cells

The design of photoanode with highly efficient light harvesting and charge collection properties is important in photoelectrochemical (PEC) cell performance for hydrogen production. Here, we report the hierarchical In₂O₃:Sn/TiO₂/CdS heterojunction nanowire array photoanode (ITO/TiO₂/CdS-nanowire array photoanode) as it provides a short travel distance for charge carrier and long light absorption pathway by scattering effect. In addition, optical properties and device performance of the ITO/TiO₂/CdS-nanowire array photoanode were compared with the TiO₂ nanoparticle/CdS photoanode. The photocatalytic properties for water splitting were measured in the presence of sacrificial agent such as SO₃²⁻ and S²⁻ ions. Under illumination (AM 1.5G, 100 mW/cm²), ITO/TiO₂/CdS-nanowire array photoanode exhibits a photocurrent density of 8.36 mA/cm² at 0 V versus Ag/AgCl, which is four times higher than the TiO₂ nanoparticle/CdS photoanode. The maximum applied bias photon-to-current efficiency for the ITO/TiO₂/CdS-nanowire array and the TiO₂ nanoparticle/CdS photoanode were 3.33% and 2.09%, respectively. The improved light harvesting and the charge collection properties due to the increased light absorption pathway and reduced electron travel distance by ITO nanowire lead to enhancement of PEC performance.     

Photocurrent and photoelectrochemical hydrogen production with tin porphyrin and platinum nanowires immobilized with nafion on glassy carbon electrode

Platinum nanowires mixed with Tin meso-tetra (4-pyridyl) porphine dichloride and nafion solution was used to modify the surface of glassy carbon electrode for photocurrent generation and photo-electrochemical hydrogen production. Different concentrations of porphyrin (50 μM, 100 μM, 300 μM and 500 μM) and platinum loading (200 μg/cm², 400 μg/cm², 600 μg/cm² and 800 μg/cm²) were tested at −150 mV Vs Ag/AgCl in reaction cell containing the modified glassy carbon electrode as working electrode, platinum wire as counter electrode and Ag/AgCl as reference electrode, under illumination to determine the optimum, based on photocurrent production in 50 mM potassium hydrogen phthalate buffer (pH 3) containing 0.1Na₂SO₄ as supporting electrolyte. Optimum photocurrent was obtained at 100 μM tin porphyrin and 600 μg/cm² platinum loading. Detectable amount of hydrogen was produced at −350 mV Vs Ag/AgCl under irradiation with visible light.     

Synergistic effect of titanium oxide underlayer and interlayer on zirconium-doped zinc ferrite photoanode for photoelectrochemical water splitting

Here, we report the synergistic effect of dual TiO₂ layers to enhance the PEC performance of Zirconium-doped zinc ferrite (ZZFO) photoanode by improving the charge carrier density and suppressing the photogenerated charge recombination. The TiO₂ underlayer works as a blocking layer to remarkably suppress the back-injection of electrons from the fluorine-doped tin oxide (FTO) leading to reducing the bulk charge recombination. While interlayer TiO₂ improves the bulk charge transfer property of ZZFO photoanodes. The optimal TiO₂ double-layer modified ZZFO photoanode exhibits an enhanced photocurrent of 0.435 mA/cm² at 1.23 V vs. reversible hydrogen electrode (RHE), which is 2.5 times higher than that of the ZZFO photoanode. The effect of each layer was deeply investigated by electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS) and time-resolved photoluminescence studies (TRPL) with the aim of gaining a clear picture of the interface modifications and their impact on the efficiency of the ZZFO photoanode.     

Nickel-doped TiO2 and thiophene-naphthalenediimide copolymer based inorganic/organic nano-heterostructure for the enhanced photoelectrochemical urea oxidation reaction

To overcome the global challenges of energy crises and environmental threats, urea oxidation is a hopeful route to utilize urea-rich wastewater as an energy source for hydrogen production. Herein, we report an inorganic/organic type of nano-heterostructure (NHs–Ni-TiO₂/p-NDIHBT) as a photoanode with excellent urea oxidation efficiency driven by visible light. This heterostructured photoanode consists of nickel (Ni)-doped TiO₂ nanorods (NRs) arrays as an inorganic part and a D-A-D type organic polymer i.e p-NDIHBT as an organic part. The as-prepared photoanode was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The morphological studies of TEM confirm the coating of p-NDIHBT on Ni–TiO₂ NPs (～1 μm). The consequence of heterostructure formation on optical and photoelectrochemical (PEC) properties of photoanode were explored through photoelectrochemical responses under visible light irradiation. The photoelectrochemical activity of Ni–TiO₂ and Ni–TiO₂/p-NDIHBT photoanode from linear sweep voltammetry (LSV) shows the ultrahigh photocurrent density of 0.36 mA/cm² and 2.21 mA/cm², respectively measured at 1.965 V_RHE. Electrochemical impedance spectroscopy (EIS) of both photoanodes shows a highly sensitive nature toward the urea oxidation reaction. The hybrid photoanode also exhibits high photostability, good solar-to-hydrogen conversion efficiency, and high faradaic efficiency for urea oxidation.     

3D cross-linked BiOI decorated ZnO/CdS nanorod arrays: A cost-effective hydrogen evolution photoanode with high photoelectrocatalytic activity

ZnO/CdS photoanode with an excellent photoelectrochemical (PEC) performance for water splitting to produce hydrogen, but its practical application is seriously hindered owing to the photocorrosion induced by photoholes on the surface of CdS. Herein, a 3D cross-linked heterostructure ZnO/CdS/BiOI nanorod arrays (NRAs) has been prepared by a simple solvothermal strategy. Under visible light illumination (λ > 420 nm), the ZnO/CdS/BiOI NRAs photoanode shows an excellent PEC activity and generates a photocurrent density of 9.12 mA cm⁻² at 1.1 V vs. RHE, which is 1.8 times higher than that of the ZnO/CdS NRAs photoanode in the alkaline electrolyte. Furthermore, the photoanode achieves a high photo conversion efficiency of 3.49% and a long-time stability over 6000 s. It is proposed that the BiOI nanosheets not only serve as protecting layer to restrain the photocorrosion of CdS, but also facilitate the charge separation in CdS by the virtue of the p-n junction formed between CdS and BiOI.     

Bi2S3 entrenched BiVO4/WO3 multidimensional triadic photoanode for enhanced photoelectrochemical hydrogen evolution applications

The catalytic reactivity and photoactivity of WO₃ and BiVO₄ oxide semiconductors have general obstacles as electrodes in emergent photo-electrochemical (PEC) hydrogen evolution applications. The present work comprises the integration of photocatalyst with wide visible photon absorption material which is vital for hydrogen evolution in photo-electrocatalytic water splitting. Herein, the 1D WO₃ NWs have been integrated with stable water oxidation photocatalysts of BiVO₄ and Bi₂S₃ as a photoanode (Bi₂S₃/BiVO₄/WO₃) for photoelectrochemical hydrogen evolution reactions. The morphological variations in the Bi₂S₃/BiVO₄/WO₃ heterostructure manifest catalytic activity and rapid charge transfer characteristics owing to band alignment and a wide range of visible photon absorption. The optimized Bi₂S₃/BiVO₄/WO₃ multidimensional photoanode accomplishes a superior photocurrent density of 1.52 mA/cm², a seven-fold higher than pristine WO₃ photoanode counterpart (0.2 mA/cm²) at 1 V vs. RHE. A prodigious lowest onset potential of ?0.01 V vs. RHE) has been achieved which enables very high solar to hydrogen conversion. The photoelectrode with entangled morphology such as nanosheets, nanocrystals and nanorods expanded their surface to volume ratio having enhanced catalytic performance. The hybrid photoanodes have demonstrated the lowest charge transfer resistance of 360 Ohm/cm² with a 7-fold rise in hydrogen evolution performance. The resultant triadic Bi₂S₃/BiVO₄/WO₃ heterostructure appeared to be an emerging stable photo-electro catalyst for hydrogen evolution applications.     

Photoelectrical and charge transfer properties of hydrogen-evolving TiO2 nanotube arrays electrodes annealed in different gases

TiO₂ nanotube arrays were fabricated by sonoelectrochemical anodic oxidation and calcined in nitrogen, air, or 5% hydrogen/nitrogen which was denoted as TNT-A, TNT-N, and TNT-H, respectively. All annealed TiO₂ nanotube arrays samples exhibited similar surface morphology. With UV illumination (365 ± 15 nm), the photocurrent density of the TNT-A, TNT-N and TNT-H was about 0.27 mA/cm², 0.45 mA/cm² and 0.60 mA/cm², respectively. The trapped electron at the Ti⁴⁺ center of TiO₂ nanotube arrays shows absorption at around 500-700 nm. From the XPS measurement, it was found that annealing in 5% hydrogen/nitrogen helped the sample obtain a greater defect density. Because of the reduction of Ti⁴⁺ and the formation of oxygen vacancies, the charge transfer resistance appeared in this order: TNT-A > TNT-N > TNT-H. Thus TNT-H harvested the greatest charge carrier density of 9.86 × 10²⁰ cm⁻³, TNT-N and TNT-A obtained a charge carrier density of 1.38 × 10²⁰ cm⁻³ and 1.06 × 10²⁰ cm⁻³, respectively. Accordingly, the hydrogen production rate by water splitting over TNT-A, TNT-N and TNT-H (320-780 nm irradiation, 3 h) was about 120 μL/h cm², 159 μL/h cm² and 231 μL/h cm², respectively.     

Synthesis and characterizations of graphene/Sm doped BiFeO3 composites photoanode for efficient photo-electrochemical water splitting

The present study features Bi_1-xSm_xFeO₃ (BSFO) nanoparticles anchored on high-quality, reduced graphene oxide (RGO) sheets via a two-step ultrasonication method for photo-electrochemical (PEC) studies relating to solar hydrogen generation. Sm doping leads to the formation of pure BFO type phase without any secondary phases. The structural, morphological, optical, and local structure analyses of BSFO and BSFO@RGO have been done through X-ray diffraction, scanning electron microscope, UV–Vis spectrophotometer, and Raman spectrometer, respectively. The BSFO nanoparticles have been templated on reduced graphene oxide. The BSFO@RGO has been employed as a photoanode for PEC measurements under the simulated solar irradiation of intensity 100 mW-cm^?1. The optimum photoanode has been found with Bi_0.95S_0.05FO₃@RGO. The highest photocurrent density and solar to hydrogen (STH) conversion efficiency have been found as 2.40 mA/cm² (at 0.5 V vs. saturated calomel electrode) and 2.45%, respectively. Furthermore, the stability of the photoanode against photo corrosion has also been tested by the chronoamperometric technique. During 2 h experiment, the average photocurrent density has been maintained at 1.5 mA/cm² (at 0 V vs. SCE). The improved photocatalytic activity of BSFO@RGO has been explained based on the effect of doping, better solar spectral response, hindering the recombination loss of photo-generated charge carriers, and fast, facile charge transport. Although earlier studies have used Bi(Sm)FeO₃ photoanode, hydrogen production has been observed for the first time in the present investigation to the best of our knowledge. Also, it appears that hydrogen production at zero external bias as observed in the present study suggests a new feature for bandgap tailored BFO.