- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
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
-
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
-
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
-
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
-
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
-
Facile designing and assessment of photovoltaic performance of hydrothermally grown kesterite Cu2ZnSnS4 thin films: Influence of deposition time
摘要： Herein, low cost precursor source Cu2ZnSnS4 (CZTS) nanocrystalline thin films at various reaction time were successfully synthesized via one step hydrothermal route. Hydrothermal route was employed to achieve control over the size and grain growth of CZTS films. As deposited CZTS films were analyzed for its optoelectronic, structural, morphological and electrochemical properties to investigate the effect of hydrothermal reaction time on growth and photovoltaic performance. The hydrothermal synthesis promoted to high absorption (104 cm?1) of the CZTS film with a decrease in optical band gap energy from 1.52 eV to 1.41 eV. Structural study revealed that, improved crystallinity with A1 mode of vibration for pure phase kesterite CZTS structure. Morphological transition was observed from nanograins to well grown and compact nanospheres. Compositional analysis illustrates, stoichiometric CZTS film formation with the desired valence state of Cu+, Zn2+, Sn4+ and S2? elements. Current density-voltage (J-V) measurement of FTO/CZTS/(0.3 M Eu3+/Eu2+)/Graphite cell configuration shows, highest photocurrent of 2.60 mA/cm2 and open circuit voltage of 754 mV was observed for CZTS4 sample with best photoconversion efficiency (η) 3.21% under illumination of 30 mW/cm2 light intensity. Electron impedance spectroscopy (EIS) showed that, generation of lower charge transfer resistance (Rct) with increase in reaction time.
关键词： Photoelectrochemical (PEC) cell,Cu2ZnSnS4 thin films,Electron impedance spectroscopy,Hydrothermal route
更新于2025-09-19 17:13:59
-
Compared with a-Fe2O3 and ZnxFe3-XO4 Thin Films Grown by Chemical Spray Pyrolysis
摘要： This work describes hematite (a-Fe2O3) and ZnxFe3-XO4 thin films prepared by Chemical Spray Pyrolysis (CSP) method. CSP method allows an optimal control of stoichiometry and impurity incorporation, hematite films modified with Zn2+ was also prepared. Moreover, the most attracting characteristics of the hematite are its stability in neutral and basic solutions, abundance and band gap energy (2.0–2.2 eV) which permits it to absorb approximately 40% of the incident solar spectrum on earth. Nevertheless, the performance of hematite electrodes for water oxidation is restricted by their poor charge transport properties. Hematite has low conductivity and low charge-carrier mobility. In addition, the photoexcited electron–hole pairs have short life time (~10-12 s), which makes the hole diffusion length to be also short (2–4 nm). The charge transport properties of hematite can be improved by dopping. We demonstrated to increase the conductivity of hematite by dopping it with metal cations with 2+ charges which improved the photocatalytic properties. Doping with metal cations with 2+ charges has also brought good photoelectrochemical results. So we iron oxide and Zn-doped iron oxide compounds have been investigated. The structural, optical and magnetic properties of a-Fe2O3 and ZnxFe3-xO4 compounds have been extensively investigated. XRD, XPS, Raman, FE-SEM and AFM techniques have been used for structural analysis; Absorption technique has been used for optical properties; Hall and Vibrating Sample Magnetometer (VSM) techniques have been used for magnetic properties.
关键词： Hematite,Thin film,Photoelectrochemical (PEC),Zn-doped iron oxide
更新于2025-09-09 09:28:46
-
Energy Band Gap Modulation in Nd-doped BiFeO <sub/>3</sub> /SrRuO <sub/>3</sub> Heteroepitaxial for Visible Light Photoelectrochemical Activity
摘要： The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer, and thus alters the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principles calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
关键词： density functional theory (DFT),heterojunction band offsets,charge transfer,Nd-doped BiFeO3,photoelectrochemical (PEC)
更新于2025-09-04 15:30:14