Electrodeposition of CdS onto BiVO4 films with high photoelectrochemical performance

In this study, CdS/BiVO 4 heterojunction was successfully synthesized on the FTO-coated glass substrate through electrodeposition annealing followed by the second electrodeposition. First, the BiVO 4 films were prepared by electrodepositing nanoporous BiOI, and then, it was converted to BiVO 4 via annealing. Then, CdS was electrodeposited onto the BiVO 4 /FTO electrode. The obtained CdS/BiVO 4 heterojunction shows higher photoelectrochemical (PEC) performance and higher stability for PEC water splitting than the blank BiVO 4 films. The maximum photocurrent density of 6.6 mA cm −2 at 0.4 V vs Ag/AgCl was obtained for CdS/BiVO 4 /FTO, which is 4.2 times of that of the blank BiVO 4 /FTO (1.6 mA cm −2 ). The enhancement mechanism of the CdS/BiVO 4 /FTO heterojunction was investigated. The CdS achieves the efficient visible light absorption and forms heterostructure with BiVO 4 , which promotes the separation efficiency of photogenerated electron-hole pairs in BiVO 4 to enhance PEC performance of CdS/BiVO 4 heterojunction.