Electrodeposition of CdS onto BiVO4 films with high photoelectrochemical performance

Abstract

In this study, CdS/BiVO4 heterojunction was successfully synthesized on the FTO-coated glass substrate through electrodeposition annealing followed by the second electrodeposition. First, the BiVO4 films were prepared by electrodepositing nanoporous BiOI, and then, it was converted to BiVO4 via annealing. Then, CdS was electrodeposited onto the BiVO4/FTO electrode. The obtained CdS/BiVO4 heterojunction shows higher photoelectrochemical (PEC) performance and higher stability for PEC water splitting than the blank BiVO4 films. The maximum photocurrent density of 6.6 mA cm−2 at 0.4 V vs Ag/AgCl was obtained for CdS/BiVO4/FTO, which is 4.2 times of that of the blank BiVO4/FTO (1.6 mA cm−2). The enhancement mechanism of the CdS/BiVO4/FTO heterojunction was investigated. The CdS achieves the efficient visible light absorption and forms heterostructure with BiVO4, which promotes the separation efficiency of photogenerated electron-hole pairs in BiVO4 to enhance PEC performance of CdS/BiVO4 heterojunction.