Synthesis And Study On Photoelectrocatalytic Properties Of Hydrogen Treatment CuWO₄

Energy crisis and environmental pollution problems have become increasingly serious. It is urgent to explore new energy sources and to develop an economic and efficient new energy technology. Semiconductor photocatalytic technology with its cheap, no secondary pollution, good stability and other advantages has a great application prospects in the use of solar energy to solve the current energy crisis and environmental pollution control. For the past few decades, some metal oxides, such as TiO2, Zn O, WO3, CeO2 and-Fe2O3 and sulfide?CdS and ZnS?, have been the primary choice of photoelectrodes for PEC water oxidation because of their low cost and high chemical stability. However, these metal oxides have not been satisfactory because they have narrow spectral response range, photoetching, high charge carrier recombination and poor stability. At present, an attractive and promising ternary metal oxide for photoanode is n-type CuWO₄ with a favorable band gap and exhibits stability property for water splitting in neutral pH electrolyte. The existing methods of synthesizing CuWO₄ are prepared into powder because the CuWO₄ is double metal oxide, however, which is made of the electrode in the photoelectrochemical?PEC? water oxidation. Therefore it is urgently the subject of research to prepare CuWO₄ photoanode and used for the PEC water oxidation. Nevertheless, no significant improvement in the efficiency of CuWO₄ as a photocatalyst for water oxidation is observed. Therefore, it is necessary to improve the transport properties and electron transfer kinetics of CuWO₄. In this paper, the CuWO₄ was modified by hydrogenation treatment, and its photocatalytic performance was improved.The main research content and results of this paper is divided into two parts:?1?Method for preparing CuWO₄/FTO photoanode: CuWO₄ films with nanoparticle on fluorine-doped tin oxide?FTO? substrates were prepared by hydrothermal synthesis. Then we discussed the effects of different hydrothermal concentrations and different hydrothermal solvents on the structure of CuWO₄ thin films. At the same time, the morphology, surface state, band gap structure and photo catalytic activity of CuWO₄/FTO prepared by hydrothermal method were characterized.?2?The prepared CuWO₄ films were treated in hydrogen atmosphere at constant temperature 300 °C for different annealing time and used for photoelectrochemical?PEC? water oxidation. Compared with pristine CuWO₄ film, the optimized hydrogen-treated CuWO₄ film presented three times enhanced photocurrent density of 0.75 mA/cm2 at 1.2 V vs.Ag/AgCl in 0.1 M Na2SO4 solution under the illumination. The mechanism of the photocatalytic activity of CuWO₄ modified by hydrogen treatment was discussed. The donor density of hydrogenated CuWO₄ film determined by Mott–Schottky, XPS, PL, Raman, UV-vis analyses was improved. The enhanced photoelectrochemical activity could be attributed to the formation of defect levels?oxygen vacancies? after hydrogen treatment, which changed CuWO₄ bandgap. Additionally the defect level?oxygen vacancies? who plays the role of electron capture, improving the carrier separation efficiency.