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Wafer-Scale Si Nanoconed Arrays Induced Syngas in the Photoelectrochemical CO2 Reduction
摘要： Photoelectrochemical (PEC) CO2 reduction offers a promising way to carry out the CO2 sequestration and develop the carbon-neutral technology. Doped Si is by far one of the most technologically important semiconductors with high conductivity and narrow bandgap, potential for CO2 reduction. However, the previous reports on PEC CO2 reduction over Si electrodes were not involved with many nanostructures. Syngas, a kind of chemical feedstocks and a crucial intermediate for hydrocarbon fuels, is highly demanded for industry. Herein, we used a wafer-scale nanoconed Si arrays substrate to load the metallic nanoparticles (Au and Cu). Effective PEC CO2 reduction into syngas was achieved in the aqueous solution with no sacrificial reagents. In contrast, planar Si seldom generated CO under the same reactant environment. Our finding deepens the comprehension of PEC CO2 reduction over the nanostructured materials and gives an inspiration for rational design of the PEC catalysts towards solar-to-chemical conversion.
关键词： Si,photoelectrochemical (PEC),CO2 reduction,nanostructure,syngas
更新于2025-11-19 16:51:07
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Visible light active CZTS sensitized CdS/TiO2 tandem photoanode for highly efficient photoelectrochemical hydrogen generation
摘要： A tandem photoanode consisting of Cu2ZnSnS4 (CZTS) nanoparticles layer over CdS/TiO2 heterostructure thin film on FTO substrate has been fabricated for photoelectrochemical hydrogen generation. CdS thin film has been deposited by chemical bath deposition over the spin-coated TiO2 thin film, which is followed by the deposition of CZTS nanoparticles layer by spray coating technique resulting in a CZTS/CdS/TiO2/FTO photoanode. The coating of CZTS nanoparticles layer over CdS/TiO2 films resulted in the tandem structure of different band level positions, which enhances the optical absorption in the visible region and also leads to higher separation of the photogenerated charge carriers. A substantial enhancement (39 times) in the PEC activity has been demonstrated for the CZTS/CdS/TiO2/FTO photoanode as compared to TiO2/FTO photoanode, which is due to cascade band gap from 3.2 eV to 1.7 eV and formation of heterojunction at interfaces. The enhancement in the charge transport properties of CZTS/CdS/TiO2/FTO photoanode has been confirmed from the electrochemical impedance spectroscopy (EIS) measurement. The EIS results confirm that the CZTS/CdS/TiO2/FTO photoanode exhibited lowest charge transfer resistance (Rct = 302 Ω/cm2) as compared to CdS/TiO2 (Rct = 615 Ω/cm2) and TiO2 (Rct = 1700 Ω/cm2) photoanode. A mechanism depicting the enhanced the performance of photoelectrochemical (PEC) CZTS/CdS/TiO2/FTO photoanode has been proposed.
关键词： EIS,Hydrothermal,PEC,Hydrogen generation,CZTS nanoparticles
更新于2025-10-22 19:40:53
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Influence of thermal oxidation temperature on the microstructure and photoelectrochemical properties of ZnO nanostructures fabricated on the zinc scraps
摘要： In this paper, zinc oxide (ZnO) nanowires were synthesized by thermal oxidation method of zinc scrap at various temperatures ranging between 400 °C and 900 °C under air atmosphere. The influence of different temperature on the phase structures, surface morphologies and photoelectrochemical (PEC) properties of ZnO nanowires were investigated. The characterizations were carried out via X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results showed that annealing temperature played a significant role on surface morphology and phase structure. The band gap energy of the ZnO nanowires changed between 3.12 and 3.194 eV. The photoelectrochemical (PEC) study of the ZnO nanowires was investigated in 0.1 M Na2SO4 aqueous solution. The PEC findings represented that the ZnO nanowire annealed at 600 °C had 252.2 mA/cm2 net photocurrent density which was the best efficiency and at least 10 times higher than that of the lowest one at 1.25 V (vs. VRHE). Mott-Schottky analysis showed that the ZnO nanowires behaved as n-type semiconductor. ZnO nanowire annealed at 600 °C had the highest carrier density value (Nd = 9.03 × 10^23). Moreover, the charge transfer behavior of the ZnO nanowires was determined by means of electrochemical impedance spectroscopy (EIS) measurements. As a result, this work recommends that the ZnO nanowires could be good candidate on PEC applications. Also, thermal oxidation method is an efficient method for fabrication of ZnO nanowires.
关键词： Thermal oxidation,Zn scrap,Electrochemical impedance spectroscopy (EIS),ZnO nanowires,Photoelectrochemical (PEC)
更新于2025-09-23 15:23:52
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In-situ approach to fabricate BiOI photocathode with oxygen vacancies: Understanding the N2 reduced behavior in photoelectrochemical system
摘要： The adsorption and activation of N2 on the catalyst surface is a major problem in the process of photoelectrochemical (PEC) N2 reduction. Herein, we report a strategy to fabricate intrinsic BiOI (I-BiOI) photocathode with oxygen vacancies (OVs) (R-BiOI) by a facile in-situ method, and the R-BiOI was successfully selected as the model matrix for understanding the role of OVs in the PEC N2 reduction system for the first time. The correlation between carrier concentration/Lewis-base/active sites and OVs was in-depth demonstrated by Mott-Schottky plots and photoelectrochemical impedance spectroscopy (PEIS) results, meanwhile the Linear-sweep-voltammetry (LSV) data further confirmed the selectivity for active N2 over R-BiOI photocathode. The tandem built from BiVO4 photoanode and R-BiOI photocathode presented the desirable production rate of ammonia at about 1.4 mmol/m2/h, which is 1.3 and 2.9 times than that of I-BiOI (1.1 mmol/m2/h) and Pt (0.48 mmol/m2/h). Our findings have initially developed the proposed mechanism for the behavior of solar-electron-ammonia conversion and offered an alternative potential route for green N2 fixation.
关键词： Active sites,Lewis-base,Oxygen vacancies,BiOI,Photoelectrochemical (PEC) N2 fixation
更新于2025-09-23 15:23:52
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Operando observation of chemical transformations of iridium oxide during photoelectrochemical water oxidation
摘要： Iridium oxide is one of the few catalysts capable of catalyzing the oxygen evolution reaction (OER) in both acidic and basic conditions. Understanding the mechanism of IrOx under realistic photoelectrochemical conditions is important for the development of integrated water splitting systems. Herein, we have developed a highly efficient OER photoanode in pH 1 aqueous solutions based on a sputtered IrOx film and a p+n-Si light absorber, interfaced with sputtered Au layer. Operando high energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD XAS) was employed to monitor the oxidation state changes of IrOx during both electrochemical and photoelectrochemical (PEC) water oxidation reactions in pH 1 aqueous solutions. We observed a gradual increase of the average oxidation state of Ir with increasing anodic potential in the pre-catalytic region, followed by a reduction of Ir under O2 evolution conditions. Consistent results were obtained on dark anodes and illuminated photoanodes. However, when the thickness of IrO2 was increased to 2 and 3 nm, the spectral changes became much less pronounced and the reduction of Ir oxidation state after the OER onset was not observed. This is due to the lower surface to bulk ratio, where lattice oxygen sites in the bulk are not accessible for the formation of hydroxide. More generally, the operando method developed here can be extended to other materials, thereby providing a powerful tool for mechanism discovery and an enabling capability for catalyst design.
关键词： oxygen evolution reaction (OER),electrochemical and photoelectrochemical (PEC),high energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD XAS),iridium oxide,Operando method
更新于2025-09-23 15:23:52
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Elucidation of the structural and charge separation properties of titanium-doped hematite films deposited by electrospray method for photoelectrochemical water oxidation
摘要： Elemental doping is considered to be an effective strategy to improve the photoelectrochemical (PEC) activity of hematite (a-Fe2O3) as a photoanode for water splitting, but the precise function(s) of the dopant remains unclear. In this study, we report on the structural and charge separation properties of titanium-doped hematite (Ti doped Fe2O3) films prepared by a simple electrospray technique for PEC water oxidation. The effect of Ti doping on the structure, morphology, light absorption, and electrical and photoelectrochemical properties was investigated on a-Fe2O3 films. SEM images revealed a reduction in particle sizes for 2% Ti doped a-Fe2O3, while an increase in particle size was observed for higher Ti content. XRD confirmed the presence of a-Fe2O3 without any impurity or other phases. From XPS spectra, the incorporation of Ti was confirmed in the form of Ti4+ as predominant species while no impurities from the substrate were detected. When the Ti doped Fe2O3 (2% Ti) film was used as a photoanode in a PEC cell, it delivered the best performance with a maximum photocurrent density of 1.09 mA cm-2 (at 1.8 V vs. RHE and under standard 1 sun illumination conditions (AM 1.5 G, 100 mW cm-2)), which is 2 times higher than that of the un-doped a-Fe2O3 (0.51 mA cm-2). The photoelectrode also showed a superior incident photon to current efficiency (IPCE) as compared to an un-doped a-Fe2O3. This enhancement in performance was attributed to the better charge separation and transport properties of a-Fe2O3 due to Ti doping, as revealed by an electrochemical impedance spectroscopy (EIS) analysis.
关键词： Electrospray deposition,PEC,a-Fe2O3,Ti doping,Water splitting
更新于2025-09-23 15:23:52
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Photoelectrochemical hydrogen production from water splitting using heterostructured nanowire arrays of Bi2O3/BiAl oxides as a photocathode
摘要： To date, most metal oxide-based photocathodes used in photoelectrochemical cells for water splitting contain copper cations in its composition, which can be reduced to metal Cu under cathodic bias leading to deactivation of the photoelectrode. Here, a Cu-free photocathode composed by a ternary heterostructure of Bi2O3/Al2Bi24O39/Al2Bi48O75 nanowires is reported with a narrow band gap energy (1.83 eV) and suitable conduction band edge potential (?0.98 VRHE) for water reduction to hydrogen. Photoelectrochemical measurements display that the highest photocurrent density of ?4.85 mA cm?2 at 0 VRHE under simulated sunlight is achieved by tuning the Bi:Al molar ratio of photocathode to 21:1. The photocurrent onset potential of the Bi2O3/BiAl oxides photoelectrode was estimated to be 0.57 VRHE at pH 7, which is comparable to that of silicon. Controlled potential photoelectrolysis at 0 VRHE showed a stable photocurrent of about ?2 mA cm?2 for 2 h of continuous operation. The H2 measured at this time was 696 μmol cm?2, which corresponds to a Faradaic efficiency of 93%. Finally, this work gives a new generation of Cu-free photocathodes and demonstrates a promising future of BiAl oxides in constructing photoelectrochemical devices for water splitting.
关键词： Oxides,Solar energy,PEC cells,Water reduction,Spray pyrolysis,Heterojunction
更新于2025-09-23 15:23:52
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Synthesis of oxygen deficient bismuth oxide photocatalyst for improved photoelectrochemical applications
摘要： The present paper reports the effect of nitrogen modification on photoelectrochemical (PEC) water oxidation behavior of Bi2O3 semiconductor thin film. The semiconductor particles were synthesized via hydrothermal route using Bi(NO3)3 as a Bi3+ ion precursor and urea as the nitrogen source followed by drop-cast the particles and annealing the film at 600oC. The synthesized Bi2O3 exhibited band gap energy of 3.01 eV, calculated from the UV-vis absorption spectrum which decreases to 2.75eV through N-modification. Water oxidation behavior of the material has been tested through linear sweep voltammetry under periodic illumination. Highest photo-current of 180 μAcm-2 has been measured for water oxidation reaction at 0.95V vs. Ag/AgCl, under illumination of 35mWcm-2. N-incorporation can enhance the photocurrent up to 50% whereas the visible responsiveness of the material improves significantly as confirmed from electrochemical action spectra and UV-visible absorption spectra. The photocatalytic activity of the semiconductor particles was confirmed through decoloration of Rhodamine-B dye, by spectrophotometric measurements.
关键词： Hydrothermal synthesis,Oxygen vacancies,Bismuth oxide photocatalyst,PEC water oxidation.,N-modification
更新于2025-09-23 15:22:29
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Pseudomorphic Transformation of Interpenetrated Prussian Blue Analogs into Defective Nickel Iron Selenides for Enhanced Electrochemical and Photo-Electrochemical Water Splitting
摘要： A significant methodology gap remains in the construction of advanced electrocatalysts, which has collaborative defective functionalities and structural coherence that maximizes electrochemical redox activity, electrical conductivity, and mass transport characteristics. Here, a coordinative self-templated pseudomorphic transformation of an interpenetrated metal organic compound network is conceptualized into a defect-rich porous framework that delivers highly reactive and durable photo(electro)chemical energy conversion functionalities. The coordinative-template approach enables previously inaccessible synthesis routes to rationally accomplish an interconnected porous conductive network at the microscopic level, while exposing copious unsaturated reactive sites at the atomic level without electronic or structural integrity trade-offs. Consequently, porous framework, interconnected motifs, and engineered defects endow remarkable electrocatalytic hydrogen evolution reaction and oxygen evolution reaction activity due to intrinsically improved turnover frequency, electrochemical surface area, and charge transfer. Moreover, when the hybrid is coupled with a silicon photocathode for solar-driven water splitting, it enables photon assisted redox reactions, improved charge separation, and enhanced carrier transport via the built-in heterojunction and additive co-catalyst functionality, leading to a promising photo(electro)chemical hydrogen generation performance. This work signifies a viable and generic approach to prepare other functional interconnected metal organic coordinated compounds, which can be exploited for diverse energy storage, conversion, or environmental applications.
关键词： MOF,PBA,electrochemical and PEC water splitting,metal-organic
更新于2025-09-23 15:21:21
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CuO/ZnO Heterojunction Nanoarrays for Enhanced Photoelectrochemical Water Oxidation
摘要： Photoelectrochemical (PEC) water splitting offers a promising route for producing chemical energy from abundant solar energy, but a bottleneck remains for PEC practical applications because of the lack of efficient, stable and earth-abundant photoelectrodes. Here, we report simultaneous improvements in carrier separation and light harvesting by constructing p-n heterojunctions in CuO/ZnO nanorod arrays. The novelty of this work is developing a new strategy for preparing a CuO/ZnO p-n heterojunction photoanode for PEC water splitting, in which Cu(OH)2/ZnO is first prepared by a chemical solution strategy and then transformed into CuO/ZnO by annealing. The CuO/ZnO heterojunction photoanode exhibited a significant negative shift of 150 mV for the onset potential and an approximately 4-fold enhancement in the photocurrent at 1.23 V vs reversible hydrogen electrode (RHE) compared with those of pristine ZnO NRs. This work offers a facile strategy for preparing oxide-based p-n heterojunction photoanodes for enhanced PEC water splitting.
关键词： Water Splitting,Light Absorption,Photoelectrochemical (PEC),Heterojunction,Photoanode,P-N Junction
更新于2025-09-23 15:21:21