Oxygen evolution NiOOH catalyst assisted V2O5@BiVO4 inverse opal hetero-structure for solar water oxidation

Using vanadium oxide (V₂O₅) inverse opal (IO) as a three-dimensional (3D) electron transporting tunnel, bismuth vanadate (BiVO₄) as a light harvester, and Amorphous Nickel Hydroxide (NiOOH) as an oxygen evolution co-catalyst, a V₂O₅@BiVO₄@NiOOH IO architecture was fabricated as an efficient photoanode on a conductive fluorine doped tin oxide (FTO) substrate for photoelectrochemical (PEC) water oxidation. V₂O₅ is the visible light absorbing photoanodes for water oxidation; however, the efficiency of this compound remains low (∼0.08 mA/cm² at 1.23 V vs. reversible hydrogen electrode (V_RHE)) and the unfavorable surface trap states limits the activity of V₂O₅ photoelectrodes in a PEC system. We found that the photoactive thin conductive BiVO₄ (∼12 nm) in the V₂O₅ IO greatly enhanced the charge separation efficiency to achieve better PEC water oxidation through modification of the surface states. The subsequent addition of NiOOH as an effective Oxygen evolution catalyst subsequently reduces the large overpotential and generates the photocurrent density of 1.14 mA/cm² at 1.23 V_RHE. Electrochemical impedance spectroscopy (EIS) evidenced that NiOOH deposition can substantially lower the charge transfer resistance (R_ct) at the semiconductor interface. Specifically, the consecutive and ordered morphology renders direct conduction pathways for the extraction of photogenerated electron/hole pairs and the convenient structure to penetrate the photogenerated carriers toward the semiconductor surface over the electrolyte. It is expected that the uninterrupted pathways will improve the electron transportation and thus the charge collection properties.     

α-Fe2O3 nanoarrays photoanodes decorated with Ni-MOFs for enhancing photoelectrochemical water oxidation

Owing to severe recombination of photogenerated charges, sluggish kinetics of oxygen evolution reaction (OER) and high overpotential, the efficiency of photoelectrocatalytic (PEC) water splitting is severely restricted currently. Herein, a metal-organic framework (Ni-MOF) as cocatalyst has been introduced onto Fe₂O₃ nanoarrays for PEC water oxidation. The new Ni-MOFs/Fe₂O₃ photoanode obviously improves the PEC water oxidation performance with respect to the Fe₂O₃. Specifically, a high photocurrent density is achieved on the Ni-MOF/Fe₂O₃ film, which corresponds to two-fold over the pristine Fe₂O₃ film at 1.23 V vs. RHE. Moreover, the photoanode also exhibits a significant cathodic shift of the onset potential (~240 mV) relative to the bare Fe₂O₃. The enhanced PEC performance is attributed to effective utilization the surface-reaching holes and reduction of the surface charge recombination, which are confirmed by electrochemical impedance spectroscopy and the derived Bode analysis. This study brings new insight into the development of MOF-based materials in the field of PEC water splitting.     

Plasmon Au modified 3D-nanostructrue CoOx decorated hematite for highly efficient photoelectrochemical water splitting

Surface modification and interface engineering are efficient strategies to address the serious charge recombination and the sluggish water oxidation kinetics in photoelectrochemical water splitting. In this work, CoO_x decorated hematite nanosheets (Fe₂O₃/CoO_x) are deposited on Nickel foam by the in-situ hydrothermal process. Au nanoparticles are incorporated on Fe₂O₃/CoO_x semiconductors (Fe₂O₃/CoO_x/Au) by electrochemical deposition. In photoelectrochemical test, Fe₂O₃/CoO_x attains a photocurrent density of 1.87 mA cm^?2 at 1.23 V_RHE, which is 4.45 times that for α-Fe₂O₃. The onset potential of Fe₂O₃/CoO_x decreases by 266 mV compared with α-Fe₂O₃. The 3D-nanostructrue Fe₂O₃/CoO_x/Au attains a photocurrent density of 3.88 mA·cm^?2 at 1.23 V_RHE, which is 9.24 times that of ɑ-Fe₂O₃. The applied bias photon-to-current efficiency, charge separation and charge injection efficiency of Fe₂O₃/CoO_x/Au are improved. EIS studies show the co-modification of CoO_x and Au reduces charge transfer resistance. This strategy would provide a potential approach to promote light absorption and charge separation for photoelectrochemical catalyst.     

Deep surface reconstruction of Co-based cocatalyst on Ti-doped α-Fe2O3 photoanode for highly efficient water oxidation

Transition metal-based cocatalysts play important roles in promoting the surface kinetics of hematite (α-Fe₂O₃) photoanode. However, their performances are restricted by the shallow reconstruction process for generating highly efficient metal oxyhydroxides, where the oxygen evolution reaction (OER) occurs. Therefore, a Brnsted base-regulated strategy is developed to promote the in situ surface reconstruction of cocatalysts on Ti-doped α-Fe₂O₃ (Ti–Fe₂O₃) under photoelectrochemical conditions. After deep surface reconstruction by electrochemical activation, the CoWO₄ cocatalyst decorated Ti–Fe₂O₃ photoanode (a-CoWO₄/Ti–Fe₂O₃) delivers a photocurrent density of 0.88 mA cm^?2 at 1.23 V_RHE, which is about 3.0 times of activated Ti–Fe₂O₃ (a-Ti-Fe₂O₃) and 1.5 times of activated CoO_x/Ti–Fe₂O₃. Tungstate promotes the surface reconstruction of cobalt-based cocatalyst, resulting in a significant increase in bulk charge separation efficiency (η_sep) and surface charge injection efficiency (η_inj). Moreover, the type-II heterojunction between CoWO₄-derived CoOOH and a-Ti-Fe₂O₃ drives the rapid separation and transfer of photogenerated electron-hole pairs, and enhances the performance of Ti–Fe₂O₃ photoanode.     

Design of efficient Mn-doped α-Fe2O3/Ti-doped α-Fe2O3 homojunction for catalyzing photoelectrochemical water splitting

To produce clean chemical fuel of hydrogen efficiently, applying photocatalysts for conducting photoelectrochemical water splitting is indispensable. Hematite (α-Fe₂O₃) has been considered as one of the most effective photocatalysts for water oxidation due to excellent visible-light responses, high stability and source abundance properties, but low electrical conductivity and slow oxidation evolution kinetics limit its application. In this study, a novel α-Fe₂O₃ homojunction is constructed via doping Ti and Mn in two layers using two-step hydrothermal synthesis followed by one-step annealing process. Co-doping effect of Ti and Mn in α-Fe₂O₃ and growing sequence of Mn doped α-Fe₂O₃ (Mn:Fe₂O₃) and Ti doped α-Fe₂O₃ (Ti:Fe₂O₃) are also investigated to illustrate the efficient design of Mn:Fe₂O₃/Ti:Fe₂O₃ homojunction. The optimized Mn:Fe₂O₃/Ti:Fe₂O₃ electrode shows the highest photocurrent density of 2.10 mA/cm² at 1.60 V_RHE respectively comparing to those of 0.10, 1.20 and 0.22 mA/cm² for Ti:FeOOH, Ti:Fe₂O₃ and α-Fe₂O₃ electrodes. The outstanding performance of Mn:Fe₂O₃/Ti:Fe₂O₃ homojunction is attributed to the smaller charge-transfer resistance, higher carrier density, and less charge recombination. This work gives a rational design for hematite-based photocatalysts and successfully attains greatly improved photocatalytic ability for water oxidation. Development of homojunction using heteroatom doping in thus verified to be highly applicable on synthesizing promising photocatalysts.     

Creation of oxygen vacancies to activate Fe2O3 photoanode by simple solvothermal method for highly efficient photoelectrochemical water oxidation

Photoelectric chemical (PEC) decomposition of water is regarded as one of the most promising ways to convert solar energy into hydrogen energy, which has attracted extensive attention from researchers at home and abroad. Among the numerous photoanode materials, α-Fe₂O₃ is considered to be one of the most promising photocatalytic materials. However, due to the poor conductivity, short photogenerated charge life and high overpotential of water oxidation reaction, the development and application of α-Fe₂O₃ is seriously hindered. Recently, the introduction of oxygen vacancies is an effective method to improve the efficiency of α-Fe₂O₃ photoelectric conversion. In this work, oxygen vacancy was introduced in Fe₂O₃ photoanode by simple solvothermal method with ethylene glycol as solvent at 160 °C. The photoelectric catalytic activity of eg-Fe₂O₃ was significantly improved for solvothermal process. At 0.186 V_SCE (1.23 V_RHE), the photocurrent density of eg-Fe₂O₃ photoanode could reach 2.8 mA/cm², which is 1–2 orders of magnitude higher than that of pristine Fe₂O₃ photoanode (0.1 mA/cm²). XPS test results show that the solvothermal process with ethylene glycol at 160 °C introduces oxygen vacancy to Fe₂O₃ photoanode. The tests of electrochemical impedance spectroscopy and photoelectrochemical impedance spectroscopy indicate that the introduction of the oxygen vacancy significantly improve the conductivity of the Fe₂O₃ photoanode and reduces the resistance of charge transmission between the electrode catalytic material and the electrolyte, which are the main reasons for the improvement of photoelectric water oxidation activity. This work provides a new method for improving the photoelectrochemical water oxidation by iron oxide photoanode.     

Photodeposited CoOx as highly active phases to boost water oxidation on BiVO4/WO3 photoanode

Surface decoration of photoanodes with oxygen evolution cocatalysts is an efficient approach to improve the photoelectrochemical water splitting performance. Herein, ultrafine CoO_x was selectively immobilized on the surface of BiVO₄/WO₃ photoanode by using the photogenerated holes to in-situ oxidize Co₄O₄ cubane. The composited photoanode (CoO_x/BiVO₄/WO₃) displayed an enhanced photoelectrochemical (PEC) water oxidation performance, with a photocurrent density of 2.3 mA/cm² at 1.23 V_RHE under the simulated sunlight irradiation, which was 2 times higher than that of bare BiVO₄/WO₃. The characterization results for the morphological, optical and electrochemical properties of the photoelectrodes revealed that, the enhanced PEC performances could be attributed to the improved charge carrier separation/transport behaviors and the promoted water oxidation kinetics when the photoelectrodes were loaded with CoO_x.     

Plasma-chemical reduction of iron oxide photoanodes for efficient solar hydrogen production

We demonstrate the effect of hydrogen plasma treatment on hematite films as a simple and effective strategy for modifying the existing substrate to improve significantly the band edge positions and photoelectrochemical (PEC) performance. Plasma treated hematite films were consist of mixed phases (Fe₃O₄:α-Fe₂O₃) which was confirmed by XPS and Raman analysis, treated films also showed higher absorption cross-section and were found to be a promising photoelectrode material. The treated samples showed enhance photocurrent densities with maximum of 3.5 mA/cm² at 1.8 V/RHE and the photocurrent onset potentials were shifted from 1.68 V_RHE (untreated) to 1.28 V_RHE (treated). Hydrogen plasma treatment under non-equilibrium conditions induced a valence dynamics among Fe centers in the sub-surface region that was sustained by the incorporation of hydrogen in the hematite lattice as supported by the density functional theory calculations.     

BiVO4 photoanode decorated with cobalt-manganese layered double hydroxides for enhanced photoelectrochemical water oxidation

Bismuth vanadate (BiVO₄) is being widely identified as a leading n-type semiconductor material for photoelectrochemical (PEC) water splitting. Nevertheless, achieving efficient PEC water oxidation process through BiVO₄ photoanode still faces serious challenge such as severe electron-hole recombination. In this case, PEC activity of BiVO₄ photoanode was enhanced by decoration of three-dimensional CoMn-layered double hydroxide (CoMn-LDH) nanoflakes on the BiVO₄ surface via a facile electrodeposition process. It was suggested that CoMn-LDH played a synergistic effect on broadening internal light absorption, which accelerated injection of holes carrier to electrolyte and alleviated the electron-hole recombination, resulting in expediting faster PEC water oxidation reaction kinetics. Consequently, the photocurrent density of BiVO₄/CoMn-LDH photoanode achieved 2.69 mA cm⁻² at 1.23 V_RHE, 2.45 times higher than the pristine BiVO₄. What's more, 220 mV negative-shift took place on onset potential that was further decreased to 0.31 V_RHE. The vastly enhanced PEC performance was also prioritized to those of Co and Mn single relatives. This work demonstrated that the synergistic BiVO₄/CoMn-LDH as a capable candidate material, can be utilized for effective PEC water splitting.     

Electrochemical reduction induced self-doping of oxygen vacancies into Ti–Si–O nanotubes as efficient photoanode for boosted photoelectrochemical water splitting

Self-doping of oxygen vacancies (V_O) states into TiO₂-based nanotubes was an efficient way for improving photoelectrochemical (PEC) water splitting properties. Here we induced oxygen vacancies into Si-doped TiO₂ (Ti–Si–O) nanotubes on Ti–Si alloy via a facile electrochemical surface reduction, and applied it for PEC water splitting. Systematic studies revealed that the self-doped oxygen vacancies not only promoted optical absorption of the doped nanotubes but also enhanced separation-transport processes of the photo-generated charge carriers, and thus resulted in improved PEC water splitting properties. The V_O/Ti–Si–O co-doping system exhibited a higher photocurrent density of 1.63 mA/cm² at 0 V vs. Ag/AgCl. Corresponding solar-to-hydrogen efficiency could reach 0.81%, which was about 5.4 times that of undoped TiO₂. It's believed that elements doping and oxygen vacancies self-doping synergistic strategy employed in this work, may provide theoretical and practical significance for designing and fabricating efficient TiO₂-based nanostructures photoanodes in PEC water splitting for boosted solar-to-hydrogen conversion.     

Surface selective passivation and FexNi1-xOOH co-modified Fe2O3 photoanode toward high-performance water oxidation

Improving the water-splitting performance of hematite (α-Fe₂O₃) is still hindered due to its severe charge recombination and poor water oxidation kinetics. Herein, borate-treated Ti–Fe₂O₃ combined with a Fe_xNi_1-xOOH cocatalyst (Fe_xNi_1-xOOH/B/Ti–Fe₂O₃) greatly improved the performance of Ti–Fe₂O₃, and reached a notable photocurrent density of 3.39 mA/cm² at 1.23 V vs. RHE. Transient surface photovoltage spectroscopy (TPV) directly reveals that [B(OH)₄]^? as a Lewis base can selectively passivate acceptor surface states on Ti–Fe₂O₃ photoanode surface, efficiently enhancing the charge separation efficiency. Moreover, the Fe_xNi_1-xOOH thin layer is devoted to further facilitate holes injection into the electrolyte, accelerating the water oxidation kinetics of Ti–Fe₂O₃ photoanode. The synergetic integration of acceptor surface states passivation and Fe_xNi_1-xOOH cocatalyst provides a novel strategy for the construction of efficient photoanodes by surface engineering.     

Novel synthesis of Ti–Fe2O3/MIL-53(Fe) via the in situ process for efficient photoelectrochemical water oxidation

The slow kinetics of water oxidation has become a challenge for photoelectrochemical hydrogen production. Here, a novel organic-inorganic integrated photoanode system was constructed by using MIL-53(Fe) formed during the in-situ etching process as a cocatalyst to modify Ti–Fe₂O₃. The photocurrent density of Ti–Fe₂O₃/MIL-53(Fe) reaches 2.5 mA/cm², 10 times that of bare Ti–Fe₂O₃ at 1.23 V vs. RHE, and the water oxidation photocurrent onset potential shifts 105 mV negatively. Ti–Fe₂O₃/MIL-53(Fe) reaches 52% at 390 nm for IPCE. The excellent photoelectrochemical performance is due to iron oxide clusters boost charge separation and transfer, in-situ etching exposes more reactive sites, and the tight connection reduces interfacial resistance, which greatly accelerates the surface kinetics of Ti–Fe₂O₃. The in-depth understanding is provided for in-situ modification of photoanodes by metal organic frameworks in this work.     

Significantly improve photoelectrochemical performance of Ti:Fe2O3 with CdSe modification and surface oxidation

Significant interest has been arisen to explore photoanodes for full optical absorption spectrums and good stability in photoelectrochemistry. Herein CdSe is used to modify Ti:Fe₂O₃ photoanode forming Ti:Fe₂O₃/CdSe heterojunction. Combining with an air annealing treatment, Ti:Fe₂O₃/CdSe exhibits a 6.5 times higher photocurrent density that of the pristine Ti:Fe₂O₃ to achieve 3.25 mA cm^?2 at 1.2 V vs. RHE. The photoelectrochemical (PEC) stability of Ti:Fe₂O₃/CdSe annealed in air shows great improvement comparable to both unannealed and annealed ones in Ar. The enhancement mechanisms for both heterojunction and annealing are explored for fundamental insights, which reveal that the surface oxide layer can significantly increase the PEC stability of Ti:Fe₂O₃/CdSe photoanode. X-ray photoelectron spectra and transmission electron microscope results further confirms the surface oxidation on CdSe layer after annealing in air.     

Charge carrier separation and enhanced PEC properties of BiVO4 based heterojunctions having ultrathin overlayers

The photoelectrochemical performance of a BiVO₄ photoanode is limited by its poor charge transport properties, despite other useful optical absorption properties. Modifying the surface charge transport properties by forming heterojunction of BiVO₄ with other metal oxides layers having ultralow thickness is a promising route, as it may facilitate charge separation/transport without affecting other properties of BiVO₄. In this study, the structural, optical and PEC properties of heterojunction of BiVO₄ having ultrathin overlayers of Fe₂O₃, MoO₃ and ZnO has been investigated. The electrochemical impedance (via electrochemical impedance spectra in PEC cell) and surface photovoltage (using KPFM) measurements indicates improved charge transport owing to staggered band alignment and favourable band bending in case of BiVO₄/MoO₃ heterojunction as compared to pristine BiVO₄, BiVO₄/Fe₂O₃ and BiVO₄/ZnO heterojunctions. Enhanced photocurrent density in BiVO₄/MoO₃ of ~0.22 mA/cm² at 1.23 V_RHE which is 6 times as compared to pristine BiVO₄ layers has been observed. The results of the present study show that by forming heterojunction with a suitable semiconductor material can be used to enhance the PEC response by modifying the surface charge transfer characteristics and there is a large possibility of using other semiconductor materials for further investigations and improvement.     

Effect of Mo-doping in SnO2 thin film photoanodes for water oxidation

New semiconducting metal oxides of various compositions are of great interest for efficient solar water oxidation. In this report, Mo-doped SnO₂ (Mo:SnO₂) thin films deposited by reactive magnetron co-sputtering in the Ar and O₂ gas environment are studied. The Sn to Mo ratio in the films can be controlled by changing the O₂ partial pressure and the deposition power of the Sn and Mo targets. Increasing the Mo concentration in the film leads to the increase in the oxygen vacancy density, which limits the maximum achievable photocurrent density. The thin films exhibit a direct band gap of 2.7 eV, the maximum achievable photocurrent density of 0.6 mA cm⁻² at 0 V_RHE and the onset potential of 0.14 V_RHE. The incident photon to current transfer (IPCE) efficiency of 22% is shown at a 450 nm wavelength. The initial performance of the Mo:SnO₂ thin films is evaluated for solar water oxidation.     

Thin-film iron-oxide nanobeads as bifunctional electrocatalyst for high activity overall water splitting

Developing only Fe derived bifunctional overall water splitting electrocatalyst both for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) while performing at low onset overpotential and with high catalytic stability is a rare instance. We present here the first demonstration of unique iron-oxide nanobeads (FeO_x-NBs) based electrocatalyst executing both OER and HER with high activity. Thin-film electrocatalytic FeO_x-NBs assembly is surface grown via simple spray coating (SC). The unique SC/FeO_x-NBs propels OER initiating water oxidation just at 1.49 V_RHE (η = 260 mV) that is the lowest observable onset potential for OER on simple Fe-oxide based catalytic films reported so far. Catalyst also reveals decently high HER activity and competent overall water splitting performance in the FeO_x-NBs two-electrode system as well. Catalyst also presents stable kinetics, with promising high electrochemically active surface area (ECSA) of 1765 cm², notable Tafel slopes of just 54 mV dec^1? (OER) and 85 mV dec^1? (HER), high exchange current density of 1.10 mA cm^2? (OER), 0.58 mA cm^2? (HER) and TOF of 74.29s^1?@1.58V_RHE, 262s^1?@1.62V_RHE (OER) and 82.5s^1?@-0.45V_RHE, 681s^1?@-0.56V_RHE (HER).     

Enhanced photocurrent by MOFs layer on Ti-doped α-Fe2O3 for PEC water oxidation

Low photocurrent density of hematite (α-Fe₂O₃) originating from the inherent defects usually hinders its application in photoelectrochemical (PEC) water oxidation. In this paper, the synergetic effect of increase of oxygen vacancies and in-situ constructing heterojunction by coating MOFs on the α-Fe₂O₃ nanoarrays gives rise to the boosted photocurrent of α-Fe₂O₃ from 0.25 mA/cm² to 2.1 mA/cm² at 1.23 V (vs. RHE). The results showed that the appropriate energy band structure engineered by the presence of MOFs layer not only facilitated the PEC water oxidation, but also enhanced the light absorption performance. With inducing oxygen vacancies in further, the intrinsic conductivity of photoanode can be well ameliorated. The value of carrier density is improved one order higher to promote charge transfer between the interfaces and raise the carrier separation efficiency as a result.     

The effects of potential and solar input on Z-scheme C3N4-TiO2 nanotubes @ Ti electrode in a broad potential window

Construction of Z-scheme graphitic carbon nitride-titanium dioxide nanotubes (C₃N₄-TNT) has been known useful to optimize the band structure for improving photon capture and for accelerating charge carrier separation and transfer rate in photoelectrochemical water splitting (PECWS) cells. However, the reported operating potential window in a PECWS cell, often in 0 – 1.23 V_RHE (volt versus reversible hydrogen electrode) plus its overpotential, is too narrow to understand the C₃N₄-TNT electrode. Herein, a broad potential window of −0.5 − 2.5 V_RHE is applied to C₃N₄-TNT@Ti and recorded via the polarization test under chopped sunlight to analyze the effect of both electrons from external electrical circuit and photons from simulated sunlight. In 0 – 2.5 V_RHE, the potential enhances the photocurrent density. For example, at 1.6 V_RHE, the C₃N₄-TNT sample exhibits 1.8-time higher photocurrent density than that of pure TNT. In −0.5 − 0 V_RHE, i.e., both samples do not give photo-current response. In addition, for advanced water oxidation/reduction beyond WS to oxygen/hydrogen, a large potential window will be expected. Further, the light capture ability, the charge carrier recombination rate, and the electron flow path through the C₃N₄-TNT junction without and with reverse/forward potentials are discussed to elucidate the effect of the applied potential.     

Enhanced photoelectrochemical performance of an α-Fe2O3 nanorods photoanode with embedded nanocavities formed by helium ions implantation

Hematite is a prospective semiconductor in photoelectrochemical (PEC) water oxidation field due to its suitable bandgap for the solar spectrum absorption. Nevertheless, the low transfer and separation efficiency of the charge carriers are restricted by its diffusion length of hole which is 2–4 nm and further reduce the PEC performance. Here, we report an innovative method, by introducing nanocavities into the α-Fe₂O₃ nanorod arrays photoanodes through helium ions implantation, to improve the charge carriers' transfer and separation efficiency and further to enhance water oxidation performance. The result indicates that, the photocurrent density of nanocavities embedded α-Fe₂O₃ photoanode (S2-A sample) reaches 1.270 mA/cm² at 1.6 V vs. RHE which is 1-fold higher than that of the pristine α-Fe₂O₃ (0.688 mA/cm²) and the photocurrent density of S2-A sample reaches 0.652 mA/cm² at 1.23 V vs. RHE. In this work, the ion implantation combined with post annealing method is found to be a valid method to improve the photoelectrochemical performance, and it also can be further used to modify the other semiconductor photoelectrodes materials.     

Coupling surface modification with cocatalyst deposition on BiVO4 photoanode to enhance charge transfer for efficient solar-driven water splitting

Bismuth vanadate (BiVO₄) has attracted wide attention as photoanode in water-splitting photoelectrochemical (PEC) devices. However, its catalytic performance is greatly limited by the serious charge recombination on the surface states. Herein, borate modified BiVO₄ plus additional CoPi cocatalyst (B-BVO/CoPi) is developed as photoanode for PEC cell via a simple soaking and electrodeposition process. Based on the electrochemistry tests and material characteristics, the borate groups [B(OH)₄] ^– is able to effectively prevent the charge recombination, while the outer CoPi cocatalyst enhance the activity toward oxygen evolution reaction. Therefore, the designed B-BVO/CoPi photoanode could obtain a high current density of 2.67 mA cm⁻² at 1.23 V_RHE with an onset potential of 0.29 V_RHE, much higher than pristine BiVO₄ (0.78 mA cm⁻², 0.52 V_RHE). This work may provide a new insight for constructing multifunctional modified photoanodes for efficient solar conversion.