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Enhanced Photoelectrochemical Water Oxidation from CdTe Photoanodes Annealed with CdCl2
摘要： CdTe absorbs sunlight up to 830 nm and has the potential to promote efficient photoelectrochemical (PEC) water splitting. However, most CdTe photoanodes and CdTe photocathodes show positive and negative photocurrent onset potentials for water oxidation and reduction, respectively, and are thus unable to drive PEC water splitting without external applied biases. In this work, we enhanced the activity of a CdTe photoanode having an internal p-n junction during PEC water oxidation by applying a CdCl2 annealing treatment together with surface modifications. The resulting CdTe photoanode generated photocurrents of 1.8 and 5.4 mA cm-2 at 0.6 and 1.2 VRHE, respectively, with a photoanodic current onset potential of 0.22 VRHE under simulated sunlight (AM 1.5G). The CdCl2 annealing increased the grain sizes in this material and lowered the density of grain boundaries, allowing for more efficient charge separation. Consequently, a two-electrode tandem PEC cell comprising a CdTe-based photoanode and photocathode split water without any external bias at a solar-to-hydrogen conversion efficiency of 0.51% at the beginning of the reaction.
关键词： Photoanode,Overall water splitting,Photoelectrochemistry,p-n junction,CdCl2 treatment
更新于2025-09-23 15:21:01
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Balance between the explored Pt counter electrode in an electrolyte medium and the photoanode for highly efficient liquid-junction photovoltaic devices
摘要： This work investigates the effect of the ratio of the explored Pt area in the electrolyte medium and the photoanode area (REP) on the performance of dye-sensitized solar cells (DSCs). As a result, the power conversion efficiency of DSCs increases by the ascending REP. The highest power conversion efficiency, which was obtained for the cell with the REP of 64/49, was 8.40%. Furthermore, the relationship between efficiency and fabrication cost is carefully discussed in terms of reducing or enhancing the surface area of CE compared to the photoanode’s surface area. The findings in this work may propose a way for a further development of efficient and large-scale DSCs in the future.
关键词： explored Pt area,photoanode,counter electrode,Dye-sensitized solar cells
更新于2025-09-23 15:19:57
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High-Performance Silicon Photoanode Enabled by Oxygen Vacancy Modulation on NiOOH Electrocatalyst for Water Oxidation
摘要： Silicon (Si) is an attractive photoanode material for photoelectrochemical (PEC) water splitting. However, Si photoanode is highly challenging due to its poor stability and catalytic inactivity toward oxygen evolution reaction (OER). Integration of highly active electrocatalysts with Si photoanodes has been considered as an effective strategy to improve OER performance through accelerates reaction kinetics and inhibits Si photocorrosion. In this work, ultra-small NiFe nanoparticles are deposited onto n-Si/Ni/NiOOH surface to improve the activity and stability of Si photoanode by engineering the electrocatalyst and Si interface. Ultra-small NiFe can introduce oxygen vacancies via modulating the local electronic structure of Ni hosts in NiOOH electrocatalyst for fast charge separation and transfer. Besides, NiFe nanoparticles also can serve as co-catalyst exposure more active sites and as protection layer prevents Si photocorrosion. The as-prepared n-Si/Ni/NiOOH/NiFe photoanode exhibits excellent OER activity with an onset potential of 1.0 V versus reversible hydrogen electrode (RHE) and a photocurrent density of ～25.2 mA cm-2 at 1.23 V versus RHE. This work provides a promising approach to design high-performance Si photoanodes by surface electrocatalyst engineering.
关键词： photoelectrochemical water splitting,oxygen vacancies,OER activity,NiFe nanoparticles,Silicon photoanode
更新于2025-09-23 15:19:57
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Ti-MOF derived TixFe1-xOy Shells Boost Fe2O3 Nanorod Cores for Enhanced Photoelectrochemical Water Oxidation
摘要： TixFe1-xOy shells, in-situ formed from thermal treatment of a Ti-containing metal organic framework, NH2-MIL-125(Ti), significantly boost the photoelectrochemical water oxidation efficiency of Fe2O3 nanorod cores. The NH2-MIL-125(Ti) was coated on the surface of the Fe2O3 nanorods with a solvothermal process, followed by a two step calcination to afford the TixFe1-xOy shell/Fe2O3 core nanorod arrays. The TixFe1-xOy shell/Fe2O3 core nanorod array electrode exhibited much improved photoelectrochemical activities over the pristine Fe2O3 nanorod array electrode, boosting photo-current densities to 26.7 folds of that achieved by the pristine Fe2O3 nanorod array electrode at 1.23 V (vs. RHE) under illumination of simulated sun light of AM 1.5G. The success may be attributed to the much enhanced charge separation enabled by the hole trapping heterojunction of TixFe1-xOy shell/Fe2O3 core. The photoelectrochemical stability of the TixFe1-xOy shell/Fe2O3 core nanorod array electrode was excellent, retaining 98.9% of the initial photo-current density after a 5 hr continuous operation. This work is the first demonstration of MOF derived core-shell heterojunction for large improvements of PEC water splitting efficiencies, and can be readily extended to a wide range of catalyst design.
关键词： NH2-MIL-125(Ti),Fe2O3 nanorod,TixFe1-xOy shell/Fe2O3 core nanorod arrays,photoelectrochemical water oxidation,photoanode
更新于2025-09-23 15:19:57
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Solution-processed ultrathin SnS <sub/>2</sub> -Pt nanoplates for photoelectrochemical water oxidation
摘要： Tin disulfide (SnS2) is attracting significant interest due to the abundance of its elements and its excellent optoelectronic properties in part related to its layered structure. In this work, we detail the preparation of ultrathin SnS2 nanoplates (NPLs) through a hot-injection solution-based process. Subsequently, Pt was grown on their surface via in-situ reduction of a Pt salt. The photoelectrochemical (PEC) performance of such nanoheterostructures as photoanode toward water oxidation was afterward tested. Optimized SnS2-Pt photoanodes provided significantly higher photocurrent densities than bare SnS2 and SnS2-based photoanodes previously reported. Mott-Schottky analysis and PEC impedance spectroscopy (PEIS) were used to analyze in more detail the effect of Pt on the PEC performance. From these analyses, we attribute the enhanced activity of the SnS2-Pt photoanodes here reported to a combination of the very thin SnS2 NPLs and the proper electronic contact between Pt nanoparticles (NPs) and SnS2.
关键词： photoanode,Tin disulfide,SnS2-Pt heterostructure,two-dimensional material,photoelectrochemical water oxidation
更新于2025-09-19 17:15:36
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Stabilization of GaAs photoanodes by in-situ deposition of nickel-borate surface catalyst as hole trapping sites
摘要： Although semiconducting gallium arsenide (GaAs) possesses an ideal band gap for efficient solar-driven fuel synthesis, it is extremely unstable in aqueous media, undergoing facile photocorrosion and therefore is seldom used. We have addressed this stability problem to some extent using a strategy of introducing a Ni-B surface catalyst onto p/n junction GaAs by in-situ photoassisted electrodeposition. A monolithic layer of Ni-B/Ga(As)Ox was generated during the Ni-B deposition process, resulting in a Ni-B/Ga(As)Ox/GaAs photoanode structure. Such structure was optimized by varying the GaAs surface architecture, electrolyte pH value and Ni-B deposition time to achieve optimal photoelectrochemical performance, together with improved stability. The optimized photoanode (Ni-B/Ga(As)Ox/shallow GaAs with 0.5 h Ni-B deposition time (~ 900 nm thickness of Ni-B/Ga(As)Ox layer) exhibited a very high photocurrent, leading to a nearly 22 hour stable photocurrent density of 20 mA/cm2, while the bare GaAs represents 60 % photocurrent loss after three hours under continuous one sun illumination (100 mW/cm2) in an alkaline media (pH=14). This remarkable performance in both photocurrent and stability directly address the current severe limitations in the application of GaAs photoanodes for solar fuel synthesis, and maybe applicable to other unstable photoelectrodes.
关键词： Nickel borate,Photoanode stabilization,Gallium arsenide,Solar energy conversion
更新于2025-09-19 17:15:36
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Highly Efficient Photoelectrochemical Water Splitting: Surface Modification of Cobalt-Phosphate-Loaded Co <sub/>3</sub> O <sub/>4</sub> /Fe <sub/>2</sub> O <sub/>3</sub> p-n Heterojunction Nanorod Arrays
摘要： Hematite (α-Fe2O3) as a photoanode material for photoelectrochemical (PEC) water splitting suffers from the two problems of poor charge separation and slow water oxidation kinetics. The construction of p–n junction nanostructures by coupling of highly stable Co3O4 in aqueous alkaline environment to Fe2O3 nanorod arrays with delicate energy band positions may be a challenging strategy for efficient PEC water oxidation. It is demonstrated that the designed p-Co3O4/n-Fe2O3 junction exhibits superior photocurrent density, fast water oxidation kinetics, and remarkable charge injection and bulk separation efficiency (ηinj and ηsep), attributing to the high catalytic behavior of Co3O4 for the oxygen evolution reaction as well as the induced interfacial electric field that facilitates separation and transportation of charge carriers. In addition, a cocatalyst of cobalt phosphate (Co-Pi) is introduced, which brings the PEC performance to a high level. The resultant Co-Pi/Co3O4/Ti:Fe2O3 photoanode shows a photocurrent density of 2.7 mA cm?2 at 1.23 VRHE (V vs reversible hydrogen electrode), 125% higher than that of the Ti:Fe2O3 photoanode. The optimized ηinj and ηsep of 91.6 and 23.0% at 1.23 VRHE are achieved on Co-Pi/Co3O4/Ti:Fe2O3, respectively, corresponding to the 70 and 43% improvements compared with those of Ti:Fe2O3. Furthermore, Co-Pi/Co3O4/Ti:Fe2O3 shows a low onset potential of 0.64 VRHE and long-time PEC stability.
关键词： photoanode,Co3O4,Fe2O3,p–n heterojunctions,Co-Pi
更新于2025-09-19 17:15:36
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The optimization of surface morphology of Au nanoparticles on WO3 nanoflakes for plasmonic photoanode
摘要： Among many candidates for photoanode materials of photoelectrochemical (PEC) cell, nanostructured tungsten trioxide (WO3) is regarded as one of the most promising materials due to its superior electrical properties and adequate bandgap (~2.8eV) and band edge position. WO3 nanoflakes(WO3 NFs), which have merits on its high surface area and crystallinity, have been actively studied for this manner but solar-to-hydrogen (STH) efficiency of WO3 NFs based photoanode is still not sufficient both in light absorption and charge separation. Plasmon-induced enhancement using Au nanoparticles is excellent approach for both the efficiency of light absorption and charge separation of WO3. However, it still needs optimization on its amount, shape, coverage, and e.t.c. Here, we synthesized WO3 NFs by solvothermal growth and decorated gold nanoparticles on these nanoflakes by e-beam evaporation and rapid thermal annealing (RTA) process in a row. By this process, a large-area AuNPs/WO3 nanocomposite structure with various size, interparticle distance, and coverage of AuNPs were fabricated. These AuNPs/WO3 NFs type photoanode achieve high light absorption both in UV and visible range and consequently higher photocurrent density. The optimized AuNPs/WO3 nanocomposite photoanode exhibits 1.01mA/cm2 of photocurrent density, which is increased to 19.8% compared with bare WO3 nanoflakes. Field emission-scanning electron microscope(FE-SEM), X-ray Diffraction(XRD), UV-vis spectrometer analysis were measured to analyze the morphology and crystallinity and relationship between structure and PEC performance.
关键词： Au nanoparticles,WO3 nanoflakes,plasmonic photoanode,Au/WO3 hierarchical structure,LSPR
更新于2025-09-19 17:13:59
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Recent Progress in Visible Light Driven Water Oxidation Using Semiconductors Coupled with Molecular Catalysts
摘要： Hybrid systems combining the molecular catalyst and semiconductors have been demonstrated to be feasible and efficient for water oxidation under visible light illumination. Herein, we present a brief review on recent developments of constructing molecule/semiconductor hybrid systems. These hybrid systems combined molecular catalysts with dye-sensitized semiconductors or visible-light-response semiconductors. This review systematically summarizes the fabrication strategies of hybrid systems in photoelectrochemical (PEC) water splitting and powdered photocatalytic water oxidation. Furthermore, we highlight the excellent water oxidation performances and stability of different hybrid systems and provide valuable guidance to design construction strategies for more robust and capable devices.
关键词： semiconductor,photoanode,molecular catalyst,photocatalytic,water oxidation,photoelectrochemical
更新于2025-09-19 17:13:59
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Enhanced Light Absorption and Charge Carrier Management in Core‐Shell Fe2O3@Nickel Nanocone Photoanodes for Photoelectrochemical Water Splitting
摘要： Solar driven photoelectrochemical (PEC) water splitting is a clean and sustainable approach to generate green fuel, Hydrogen. Hematite (Fe2O3) is considered as potential photoanode because of its abundance, chemical stability and suitable band gap, though its short carrier diffusion length puts a limit on the film thickness and subsequent light absorption capability. In this regard, here we have designed and constructed a unique photoanode by depositing ultrathin films of Fe2O3 on purpose-built three-dimensional (3D) nickel nanocone arrays. In this design, 3D nanostructures not only provide ameliorated surface area for PEC reactions but also enhance light absorption capability in ultrathin Fe2O3 films, while ultrathin films promote charge carrier separation and effective transfer to the electrolyte. The 3D electrodes exhibit a substantial improvement in light absorption capability within the entire visible region of solar spectrum, as well as enhanced photocurrent density as compared to the planar Fe2O3 photoelectrode. Detailed investigation of reaction kinetics suggests an optimum Fe2O3 film thickness on 3D nanocone arrays obtained after 6 deposition cycles in achieving maximum charge carrier separation and transfer efficiencies (82% and 88%, respectively), mainly ascribable to the increased charge carrier lifetime overcoming recombination losses.
关键词： photoanode,nanocones,water splitting,ultrathin,photoelectrochemical
更新于2025-09-19 17:13:59