BiVO4膜电极的制备及其光电化学性能

以自制的BiVO4纳米粉制备膜电极, 采用电化学方法较系统地研究了退火温度和膜厚对BiVO4膜电极的光电化学行为和电子输运与复合的影响. 结果表明: 退火温度和膜厚对BiVO4膜电极的光电特性有显著的影响. 膜厚为6.75 μm时, BiVO4膜电极具有最佳的光电化学特性. 退火温度低于500 °C时, 膜电极的光电活性随着温度的升高而增强, 至500 °C时达到最大值; 此后膜电极内的体相缺陷明显增加, 导致其光电活性逐渐降低. BiVO4膜电极有良好的可见光光电转换效率, 并利用其单色光转换效率曲线计算得到BiVO4的带隙为2.36eV, 采用莫特-肖特基电化学法测得其平带电位为-0.7 V (vs Ag/AgCl). 上述结果为BiVO4光催化体系的优化提供了重要的参考.

Preparation and Photoelectrochemical Performance of BiVO4 Film Electrode

A BiVO4 film electrode was prepared using a home-made BiVO4 nanopowder and the effects of annealing temperature and film thickness on its photoelectrochemical behavior,electron transport and recombination in the BiVO4 electrode were systematically studied by electrochemical techniques.Experimental results indicate that the annealing temperature and film thickness can significantly influence the photoelectrochemical characteristics of the BiVO4 electrode.At low annealing temperature(≤500 °C) the photoelectrochemical activity improved upon increasing the temperature and the optimal activity was obtained for the electrode annealed at 500 °C.At high temperature(>500 °C) the photoelectrochemical activity decreased because of a marked increase of bulk traps in the electrode.The BiVO4 electrode showed good photon-to-electron conversion efficiency under visible light and its bandgap was found to be 2.36 eV based on an incident monochromatic photon-to-electric conversion efficiency curve.The flat-band potential(Efb) of BiVO4 was determined to be-0.7 V(vs Ag/AgCl) by the Mott]Schottky method.These results give an important reference for the optimization of the BiVO4 photocatalytic system.