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Mixed-metal organic framework-coated ZnO nanowires array for efficient photoelectrochemical water oxidation
摘要： Designing of high-performance photoanodes is essential for efficient solar energy conversion in photoelectrochemical (PEC) water splitting. Herein, we report an effective approach to synthesize three dimensional (3D) mixed-metal organic framework-coated ZnO nanowires array (ZnNi MOF@ZnO) for the effective PEC performance. The ZnO nanowires act as photon absorber as well as rapid charge transporter; whilst the ZnNi MOF provides the active sites for PEC process by lowering the energy barrier of water oxidation and suppressing electron-hole recombination. The 3D nanostructure of ZnNi MOF@ZnO nanowires array provides intimate interfacial contact through covalent interactions between the ZnNi MOF and ZnO nanowires which facilitates the rapid charge transfer during photocatalytic oxygen evolution reactions. As a result, the ZnNi MOF@ZnO nanowires array exhibited excellent photoelectrochemical water oxidation with very low onset potential (0.31 V vs. RHE) and high photocurrent density (1.40 mA/cm2) as compared to the Zn MOF @ZnO and ZnO nanowires array. This facile strategy provides a promising direction towards high performance photoanode design for adequate solar energy conversion.
关键词： Metal organic frameworks (MOFs),Photoelectrocatalyst,Nanowires array,Photoelectrochemical water oxidation,Photoanodes
更新于2025-09-23 15:22:29
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Layered Double Hydroxides Decorated Graphic Carbon Nitride Film as Efficient Photoanodes for Photoelectrochemical Water Splitting
摘要： In the present work, we investigate the graphic carbon nitride (g-CN) film as photoanode to catalyze the photoelectrochemical (PEC) water oxidation and study the influence of NiCo layered double hydroxides (NiCo-LDH) layer on the performance. The g-CN film with good quality and intimate contact with substrate was in-situ prepared via solvothermal process and subsequent calcination. NiCo-LDH is further decorated on the g-CN film through cathodic electrochemical deposition to work as co-catalyst. The g-CN/NiCo-LDH composite with optimized NiCo-LDH loading amount exhibits a photocurrent of 11.8 μA cm-2 at 0.6 V vs. SCE, which is 2.8 times of bare g-CN. Characterizations and performance tests demonstrate that NiCo-LDH promoted reaction kinetics and charge separation. The results provide an effective strategy to improve the photoelectrochemical water oxidation performance of g-CN through NiCo-LDH co-catalyst. This work to investigate the photoelectrochemical water oxidation is of great significance toward explore the overall water splitting on the g-CN film.
关键词： Layered double hydroxides,Solvothermal process,Photoelectrochemical water oxidation,Co-catalyst,Graphitic carbon nitride
更新于2025-09-23 15:22:29
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Ti, Zn co-doped hematite photoanode for solar driven photoelectrochemical water oxidation
摘要： Although there have been many reports of metal doping to ameliorate the drawbacks of hematite as the photoanode for water oxidation, most of them focused on monometallic doping, and only a few of them payed attention to bimetallic doping. What is worse, the synergetic mechanism between two metal dopants was not su?ciently studied, especially the density functional theory (DFT) calculation. In this work, the n-type hematite was synthesized by introducing Ti dopant into hematite through the hydrothermal method, and dipping-sintering treatment was employed to further introduce homogeneously dispersed Zn dopant into that, forming the Ti, Zn co-doped hematite. Under the optimal condition, Ti-doped hematite photoanode reached approximately 2-times enhancement of the photocurrent density compared with the pristine one at 1.23 V vs. RHE, while Ti, Zn co-doped hematite anode obtained another 25% elevation. UV –Vis spectroscopy, Mott –Schottky plots, EIS analysis, photo-oxidation of hole scavenger (H 2 O 2 ), and DFT calculation were employed to understand the role of Ti, Zn dopant. Based on the obtained results, the synergetic mechanism of two dopants was discussed, i.e., the improvement of PEC performance of Ti, Zn co-doped hematite photoanode was possibly attributed to greater carrier density and improved charge separation e?ciency at the surface of hematite. This work provides new strategy and understanding of the improvement of PEC performance of hematite by doping engineering.
关键词： Photoelectrochemical water oxidation,Zn co-doping,Ti,DFT calculation,Hematite
更新于2025-09-23 15:21:01
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Bio-template assisted hierarchical ZnO superstructures coupled with graphene quantum dots for enhanced water oxidation kinetics
摘要： Due to anisotropic growth behavior and tunable electrical properties, ZnO nanostructures having dimensions such as 0-D, 1-D, 2-D and 3-D are actively studied for their optoelectronic properties. However, ZnO based photoanodes suffer from unfavorable recombination of electron hole pair, which hinders its use in photoelectrochemical (PEC) water oxidation. Herein, we demonstrate a strategy to enhance the PEC performance using bio-template assisted in-situ grown hierarchical ZnO superstructures directly over fluorine-doped tin oxide (FTO) modified by graphene quantum dots (GQDs). GQDs decorated hierarchical ZnO superstructures displayed a significant increment of ~77% in photocurrent density value compared to pristine ZnO with an impressive carrier density of 3.19 × 1020 cm?3, which is ~1.8 orders of magnitude higher than that of pristine ZnO. It is observed that GQDs acts as an efficient hole extractor, which improves the carrier separation on ZnO surface and reduces the hole trapping probability.
关键词： Hole extracting agent,Polygalacturonic acid,Hierarchical ZnO superstructures,Photoelectrochemical water oxidation,Graphene quantum dots
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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Interfacial growth of the optimal BiVO4 nanoparticles onto self-assembled WO3 nanoplates for efficient photoelectrochemical water splitting
摘要： Photoelectrochemical water splitting is the most efficient green engineering approach to convert the sun light into hydrogen energy. The formation of high surface area core-shell heterojunction with enhanced light-harvesting efficiency, elevated charge separation, and transport are key parameters in achieving the ideal water splitting performance of the photoanode. Herein, we demonstrate a first green engineering interfacial growth of the BiVO4 nanoparticles onto self-assembled WO3 nanoplates forming WO3/BiVO4 core-shell heterojunction for efficient PEC water splitting performance. The three different WO3 nanostructures (nanoplates, nanobricks, and stacked nanosheets) were self-assembled on fluorine doped tin oxide glass substrates via hydrothermal route at various pH (0.8–1.2) of the solutions. In comparison to nanobricks and stacked nanosheets, WO3 nanoplates displayed considerably elevated photocurrent density. Moreover, a simple and low cost green approach of modified chemical bath deposition technique was established for the optimal decoration of a BiVO4 nanoparticles on vertically aligned WO3 nanoplates. The boosted photoelectrochemical current density of 1.7 mA cm?2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination was achieved for the WO3/BiVO4 heterojunction which can be attributed to a suitable band alignment for the efficient charge transfer from BiVO4 to WO3, increased light harvesting capability of outer BiVO4 layer, and high charge transfer efficiency of WO3 nanoplates.
关键词： Green hydrogen,Photoelectrochemical water oxidation,WO3/BiVO4 heterojunction,Low cost,Core-shell
更新于2025-09-12 10:27:22
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Hexagonal boron nitride quantum dots as a superior hole extractor for efficient charge separation in WO <sub/>3</sub> based photoelectrochemical water oxidation
摘要： Photoelectrochemical (PEC) water splitting is one of the best desirable technique to harvest clean chemical energy from abundant solar energy. However, the anodic half reaction, i.e. water oxidation is complicated due to the involvement of multiple electrons in this process. Herein, stable WO3 nanoblocks with monoclinic phase have been modified by incorporation of hexagonal boron nitride quantum dots (h-BNQDs) to improve the photogenerated electron-hole separation and additionally to hinder the charge recombination process. The photocurrent density (J) value for modified WO3 photoanode by incorporation of BNQDs has been found to be 1.63 mA/cm2 at the potential of 1.23VRHE which is approximately 2.4 fold higher than the bare WO3 photoanode. The enhancement in photocurrent density is mainly due to the hole extraction property of BNQDs on the surface of the WO3 nanoblocks. A two-fold increment in photogenerated charge carrier density (ND) value has been achieved due to better charge separation of electron-hole pairs in the modified system confirmed by the Mott-Schottky (MS) plot. Present work demonstrates a unique, low-cost strategy for enhancement of PEC water oxidation by modification of photoanode with hole extracting agents.
关键词： charge separation,boron nitride quantum dots,photoelectrochemical water oxidation,hole extracting agent,Tungsten trioxide
更新于2025-09-12 10:27:22
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Particulate Oxynitride Photoanodes Assembled with Transparent Electron-Collecting Oxide Nanorod Arrays
摘要： The collection of photogenerated electrons is commonly a bottleneck in photoelectrochemical water oxidation on a particulate photoanode. Herein, a new strategy called “array insertion” for particulate photoanode preparation is proposed to improve electron collection. ZnO nanorod arrays are inserted between LaTiO2N particles and Al-doped ZnO (AZO) substrates via epitaxial electrodeposition, which make electronic connections. Using this methodology, charge separation efficiency is improved drastically, and the photocurrent at 1.23 VRHE is enhanced by more than 1 order of magnitude, because the obstacle of electron collection in the particulate LaTiO2N photoanodes is overcome.
关键词： photoelectrochemical water oxidation,particulate photoanode,ZnO nanorod arrays,LaTiO2N,electron collection
更新于2025-09-11 14:15:04
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Hierarchical Ta-Doped TiO2 Nanorod Arrays with Improved Charge Separation for Photoelectrochemical Water Oxidation under FTO Side Illumination
摘要： TiO2 is one of the most attractive semiconductors for use as a photoanode for photoelectrochemical (PEC) water oxidation. However, the large-scale application of TiO2 photoanodes is restricted due to a short hole diffusion length and low electron mobility, which can be addressed by metal doping and surface decorating. In this paper we report the successful synthesis of hierarchical Ta doped TiO2 nanorod arrays, with nanoparticles on the top (Ta:TiO2), on F-doped tin oxide (FTO) glass by a hydrothermal method, and its application as photoanodes for photoelectrochemical water oxidation. It has been found that the incorporation of Ta5+ in the TiO2 lattice can decrease the diameter of surface TiO2 nanoparticles. Ta:TiO2-140, obtained with a moderate Ta concentration, yields a photocurrent of ～1.36 mA cm?2 at 1.23 V vs. a reversible hydrogen electrode (RHE) under FTO side illumination. The large photocurrent is attributed to the large interface area of the surface TiO2 nanoparticles and the good electron conductivity due to Ta doping. Besides, the electron trap-free model illustrates that Ta:TiO2 affords higher transport speed and lower electron resistance when under FTO side illumination.
关键词： hierarchical TiO2,photoelectrochemical water oxidation,Ta doping,charge separation
更新于2025-09-09 09:28:46