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Molybdenum Disulfide Catalytic Coatings via Atomic Layer Deposition for Solar Hydrogen Production from Copper Gallium Diselenide Photocathodes
摘要： We demonstrate that applying atomic layer deposition-derived molybdenum disulfide (MoS2) catalytic coatings on copper gallium diselenide (CGSe) thin film absorbers can lead to efficient wide band gap photocathodes for photoelectrochemical hydrogen production. We have prepared a device that is free of precious metals, employing a CGSe absorber and a cadmium sulfide (CdS) buffer layer, a titanium dioxide (TiO2) interfacial layer, and a MoS2 catalytic layer. The resulting MoS2/TiO2/CdS/CGSe photocathode exhibits a photocurrent onset of +0.53 V vs RHE and a saturation photocurrent density of ?10 mA cm?2, with stable operation for >5 h in acidic electrolyte. Spectroscopic investigations of this device architecture indicate that overlayer degradation occurs inhomogeneously, ultimately exposing the underlying CGSe absorber.
关键词： hydrogen evolution,molybdenum disulfide,photoelectrochemical water splitting,atomic layer deposition,copper gallium diselenide
更新于2025-11-19 16:56:35
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Photoelectrochemical enhancement from deposition of BiVO4 photosensitizer on different thickness layer TiO2 photoanode for water splitting application
摘要： TiO2 is a prominent photocatalyst and has been pioneering the research in water splitting for hydrogen cell production. However, TiO2 has low visible region absorption which limit its functionality as a photoabsorber and requires addition of other high absorptive material such as BiVO4. Fabrication of TiO2 photoanode on FTO substrate and deposition of BiVO4 on TiO2 were done using simple spin coating procedure. TiO2/BiVO4 photoelectrode were first tested for its photo absorption, photocurrent generation and electrical impedance to obtain the optimized sample. Optimized sample then further tested for its photocurrent generation stability using linear sweep voltammetry and time dependent photocurrent test. Photo absorption enhancement from TiO2/BiVO4 of almost 10 folds achieved along the visible region comparing to pure TiO2. Photogenerated charge produced from TiO2/BiVO4 is also 3 folds higher compared to pure TiO2at water oxidation threshold potential at 1.23 V vs. RHE. From photocurrent generation analysis, heterostructure of TiO2/BiVO4 proven to produce more than 3 folds higher photocurrent comparing to both pure TiO2 and BiVO4.
关键词： Z-scheme,Bismuth vanadate,Thin-film,Titanium dioxide,Photoelectrochemical water splitting
更新于2025-11-14 15:19:41
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High Temperature One-Step Synthesis of Efficient Nanostructured BiVO4 Photoanodes for Water Oxidation
摘要： Bismuth vanadate (BiVO4) is a promising photoanode material for photoelectrochemical water splitting due to its well-suited valence band edge and comparatively narrow band gap. Herein, we provide first insights on the high temperature rapid and scalable synthesis of efficient nanostructured BiVO4 photoanodes for water oxidation. Nanostructured BiVO4 films with tunable optical density and porosity from 12 to 80% have been synthesized in few seconds by direct deposition of flame-made BiVO4 nanoparticle aerosols. The impact of BiVO4 film structural properties on the photooxidation performance has been systematically investigated by a set of electrochemical and physical characterizations indicating key directions for its morphological optimization. It was found that the BiVO4 water oxidization performance is mainly determined by two competitive factors, viz. accessible surface area and carrier conductivity through the grain boundaries. Optimization of these two factors increased the photocurrent densities by more than 3 times resulting in ca 1.5 mA cm-2 for sulphite oxidation and ca 1 mA cm-2 for water oxidation with a FeOOH\NiOOH co-catalyst at 1.0 V vs. the reversible hydrogen electrode (VRHE) under simulated one sun illumination. These findings provide novel insights into the structure-activity relationships of high temperature synthesized BiVO4 photoanodes for solar-powered water splitting, and introduce a scalable and low-cost approach for their rapid nanofabrication.
关键词： Flame Synthesis,Bismuth Vanadate,Scalable,One-Step,Photoelectrochemical Water Splitting
更新于2025-10-22 19:40:53
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Plasmonic nickel nanoparticles decorated on to LaFeO3 photocathode for enhanced solar hydrogen generation
摘要： Plasmonic Ni nanoparticles were incorporated into LaFeO3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70e100 nm for Surface Plasmon Resonance (SPR) enhancement.
关键词： LaFeO3,Finite difference time domain,Surface plasmon resonance,Ni nanoparticle,Photocathode,Photoelectrochemical water splitting
更新于2025-10-22 19:40:53
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Ti3C2 MXene nanoparticles modified metal oxide composites for enhanced photoelectrochemical water splitting
摘要： MXene, an emerging family of two-dimensional (2-D) material, has shown outstanding electronic properties and promise for the applications on energy storage and conversion. In this paper, Ti3C2 MXene nanoparticles were synthesized by a facile solvent exfoliation method and used to construct metal oxide/Ti3C2 heterostructures. When these heterostructures were used as photoanodes for photoelectrochemical water splitting, significantly improved photoactivity and stability were achieved. Compared to pristine TiO2, 6-fold enhanced applied bias photon-to-current efficiency (ABPE) was achieved for TiO2/Ti3C2 heterostructures. According to the electron spin resonance, electrical impedance spectroscopic and Mott-Schottky measurements, the enhanced photoelectrochemical performance was ascribed to the presence of Ti3C2 as oxygen evolution cocatalysts and the strong interfacial interactions between metal oxide and Ti3C2. Therefore, our research provides a new way to design MXene-based heterostructures for solar energy conversion applications.
关键词： Metal oxide,MXene,Heterostructured photoanodes,Photoelectrochemical,Water splitting
更新于2025-09-23 15:23:52
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Aging of a Vanadium Precursor Solution: Influencing Material Properties and Photoelectrochemical Water Oxidation Performance of Solution-Processed BiVO <sub/>4</sub> Photoanodes
摘要： Metal–organic decomposition is an easy way to fabricate BiVO4 (BVO) photoanodes; however, it often experiences a reproducibility issue. Here, the aging duration of a vanadium precursor solution, vanadyl acetylacetonate in methanol, is identified as a factor that profoundly affects reproducibility. Substantial changes in structural, optical, and electrical properties of BVO films are observed upon varying aging time of vanadium precursor solutions, which subsequently impacts photoelectrochemical (PEC) water oxidation and sulfite oxidation reactions. With the optimum number of aging days (3 d), some deficiency of oxygen is observed, which is accompanied by an increase in carrier concentration and a reduced charge transfer resistance in the PEC device, which produces the highest PEC performance that is comparable to the state-of-the-art undoped BVO photoanodes. The findings point to the importance of understanding solution chemistry and demonstrate that utilization of the understanding of fine adjustment of the composition of BVO films can produce highly reproducible and efficient BiVO4 photoanodes.
关键词： solution aging,metal–organic decomposition,bismuth vanadate,chemical composition,photoelectrochemical water splitting
更新于2025-09-23 15:23:52
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Effect of Mo doping and NiFe-LDH cocatalyst on PEC water oxidation efficiency
摘要： The NiFe-layered double hydroxide (LDH) nanosheets were decorated on the surface of doped BiVO4 to structure an integrating photoanode for improving solar photoelectrochemical (PEC) water splitting efficiency, which is a dynamic research topic to solve the energy crisis and remit environmental pollution caused by fossil fuel combustion. The fabricated photoanode exhibits rapid response to visible light, enhances photocurrent density and shows significant cathodic shift compared to BiVO4. Moreover, the measured incident photon-to-current efficiency (IPCE) of the photoanode is comparable to that reported in the literature. The amount of evolution oxygen was measured and the faradaic efficiency produced oxygen was also obtained by comparing the theoretical calculation value. The enhancement is attributed to the increase of the carrier density, the effective separation of photogenerated electron-hole and consuming of the photogenerated holes accumulated at the electrode surface, which has been confirmed by electrochemical impedance spectra (EIS) and the intensity modulated photocurrent spectra (IMPS). The work may offer a promising method for designing a high efficiency and low-cost photoanode.
关键词： NiFe-layered double hydroxides.,BiVO4,Mo-doping,Photoelectrochemical water splitting
更新于2025-09-23 15:23:52
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Energy diagram analysis of photoelectrochemical water splitting process
摘要： Photoelectrochemical (PEC) water splitting process is thoroughly revisited based on the energy diagram to elucidate the experimental observations. The TiO2 nanorod structure is studied as the model system for the photoanode of the PEC cell due to its stability in both acidic and basic solutions. The photocurrents with the external bias are examined under the various electrolytes of H2SO4, NaCl, and NaOH. The energy diagrams of the whole PEC system related to the water splitting process are interactively constructed in three-electrode configuration with the vacuum level as the common reference. Electrode potentials and photocurrents measured with the external bias in dark and under light are systematically correlated with the energy diagram of the PEC system. The pH dependent flat-band potential is explained by applying the pH dependent Helmholtz layer potential at the interface. In addition, the distribution of the applied potential in the PEC system during the water splitting process is understood by in-depth understanding of the energy band diagram.
关键词： band analysis,TiO2 nanorod,photoelectrochemical water splitting
更新于2025-09-23 15:23:52
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ZnxCd1-xSe nanoparticles decorated ordered mesoporous ZnO inverse opal with binder-free heterojunction interfaces for highly efficient photoelectrochemical water splitting
摘要： Well-defined porous heteronanostructures with broad light absorption range and efficient charge transfer are the key challenges towards developing efficient photoanodes for photoelectrochemical (PEC) water splitting. Herein, we reported a facile template and continuous ion exchange method to fabricate three-dimensional ordered mesoporous (3DOM) ZnO/ZnxCd1-xSe inverse opal with binder-free heterojunction interfaces on F-doped SnO2 glass. The heteroepitaxial growth of ZnxCd1-xSe shell layer on ZnO inverse opal skeleton surface provided favorable type-II band alignment, low interfacial resistance, and high visible light absorption. As expected, the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal achieved a significant saturated photocurrent density of 24.76 mA cm-2 at 1.23 V versus a reversible hydrogen electrode (RHE) in 0.25 M Na2S and 0.35 M Na2SO3 aqueous solution under AM 1.5 G simulated solar light irradiation (100 mW cm-2), which is 25 times higher than that of the pristine ZnO (0.99 mA cm-2 at 1.23 V versus RHE) photoanode. The maximum photoconversion efficiency reached 10.64% for the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal at an applied potential of 0.52 V versus RHE, an about 22.63 times increase relative to that of the pristine ZnO inverse opal (0.47% at 0.61 V versus RHE). In addition, the photostability of the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal photoanode was also greatly improved in the electrolyte solution, 82.6% initial value was maintained even after 3000 s continuous light illumination without any protective coating layer. Such prominent PEC performances of the as-prepared 3DOM ZnO/ZnxCd1-xSe inverse opal can be ascribed to the improved visible light harvesting and enhanced charge separation/collection efficiency. This work provides a fundamental insight to design the efficient photoanode for high performance water splitting.
关键词： Heteroepitaxial growth,ZnO/ZnxCd1-xSe,Inverse opal,Photoelectrochemical water splitting,Heterojunction interface
更新于2025-09-23 15:23:52
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Modulated anodization synthesis of Sn-doped iron oxide with enhanced solar water splitting performance
摘要： Modulated anodization synthesis is introduced here for the fabrication of porous Sn-doped iron oxide. Continuous square-wave modulation consisting of highly positive (+50 to +80 V range) and slightly negative potentials (-2 to -10 V range) at 100 Hz allowed the etching anodization of the metallic Fe foil and incorporation of Sn-dopant from the fluoride anion-containing electrolyte, respectively. Compared with the undoped iron oxide, the surface-enriched Sn-dopant (in the form of Sn4+) alleviates the trapping and recombination of surface holes, while enhancing the hole transfer at the surface states. As such, the overpotential for photoelectrochemical (PEC) water oxidation was reduced by 110 mV and photocurrent density doubled. The incorporation of Co-Pi co-catalyst further improved the hole transfer efficiency, resulting in further reduction in overpotential by another 330 mV with respect to the bare Sn-doped iron oxide and significant improvement in photocurrent density at potentials below +1.23 V vs. reversible hydrogen electrode. Lastly, the iron oxide electrodes exhibit highly stable PEC water oxidation with no degradation in activity throughout the 10 h assessment under simulated solar irradiation and Faradaic efficiency of 90%. We envisage that the modulated anodization technique can be conveniently incorporated for a wide range of other dopants in search of efficient solar water splitting electrodes.
关键词： Doping,Hematite,Hydrogen,Photoelectrochemical water splitting,Charge transport
更新于2025-09-23 15:23:52