Electrochemically synthesized Cd doped ZnO nanorods and integrated atomic Cd-S bridged Cd:ZnO/CdS heterostructure photoanode for enhanced visible light responsive water oxidation applications

Abstract

Cd-doped ZnO and CdS-decorated ZnO:Cd/CdS heterostructure nanorod arrays (NRA) were successfully fabricated and integrated in this study. The severe surface charge recombination and weak visible light responsivity of ZnO are barriers to the PEC application. Herein, electrochemically synthesized Cd doped ZnO nanorod arrays caged with visible light responsive CdS semiconductor catalyst rehabilitated the photoelectrocatalytic characteristics of the photoanode. The chemically modified Cd:ZnO/CdS photoanode shows a notable photocurrent density of 3.6 mA/cm2(at 0.2 V vs Ag/AgCl) and a prominent onset potential that is negatively shifted by 324 mV relative to the pure ZnOphotoelectrode. The 1D CdS cage around ZnO nanorod improves the visible light responsive photo electrochemical performance with low −1.064 V vs Ag/AgCl onset potential, 740 Ohm/cm2 charge transfer resistance and 0.24% of solar to hydrogen conversion efficiency with high built-in potential (515 mV). The realized result caused by the Cd doping and heterostructure of the ZnO:Cd/CdS photoanode with an exceptional nanostructure photoanode could be a pioneering technique for cost-effective applications in the photoelectrochemistry field.