碱性电解质中BiVO4膜电极的光电化学性质

采用刮刀法制备了压制BiVO4膜电极,研究了电极在0 1 mol/L NaOH中的光电化学性质. 发现相对于中性电解质,其在碱性电解质中的光电流增大,稳定性提高. 结合循环伏安分析中间产物的还原特性,认为光催化氧化水作用是通过四空穴亲核反应历程进行的. pH值升高有利于亲核反应,过氧化物中间产物累积较少. 在较高的偏压的碱性溶液中,光氧化水的机制可能涉及铋的中间物质.

Photoelectrochemical Properties of BiVO4 Film Electrode in Alkaline Solution

A pressed BiVO4 film electrode with excellent performance has been prepared by a doctor blade method.The photoelectrochemical properties of the electrode in 0.1 mol/L NaOH have been studied.The results showed that the photocurrent and stability were better than those in the Na2SO4 electrolyte.Combined with the cyclic voltammograms for the intermediate analysis,the results indicated that the water photooxidation is a nucleophilic attack process involving four holes.The nucleophilic attack reaction is favorable in higher-pH alkaline solution,and the accumulation of peroxide intermediates is decreased.Moreover,when a higher bias is applied in an alkaline solution,the water photooxidation mechanism is more complex,and some bismuth intermediates probably are involved in the process.