Controllable synthesis of CdS nanospheres photoelectrode for photoelectrochemical water splitting

Abstract

CdS nanospheres were grown on indium tin oxide (ITO) substrate using a hydrothermal method. The crystal structure, morphology and electronic structure of the samples synthesized were characterized in detail. The results confirm that the crystallinity, size, crystal defects of the CdS nanospheres and the film thickness of CdS photoelectrodes can be tuned by varying the precursor Cd²⁺ concentration. Combined with charge transfer dynamics analysis, it can be found that proper particle size and film thickness, as well as fewer defects, will result in better charge separation efficiency of the prepared CdS/ITO photoelectrodes, thereby exhibiting better photoelectrochemical performance for water splitting. The optimized CdS/ITO photoelectrode synthesized with a Cd²⁺ concentration of 0.14 mol·L⁻¹ gave a photocurrent density of 5.10 mA·cm⁻² at potential of 1.23 V versus the reversible hydrogen electrode (RHE), under a simulated solar illumination of 100 mW·cm⁻².