Fabrication of CdS-coated ZnO nanorods arrays for photoelectrocatalytic degradation of phenol

CdS shells have been successfully deposited on ZnO nanorod arrays via using successive ionic layer adsorption and reaction (SILAR) technique upon which the thickness of the CdS shell can be accurately tuned by changing the deposition cycles. As determined by UV-Vis spectra, increasing the deposition cycles leads to a linear increment on shell thickness of CdS, and the optimal deposition cycle for realizing the best photoelectrical response is 20 layers. Photoluminescent results reveal a proper band alignment between the CdS shell and the ZnO core, benefitting from which CdS-coated ZnO nanorods exhibit good photoelectrochemical properties and high catalytic activity for removal of phenol under visible light irradiation. In the photoelectrocatalytic process, about 80% degradation of 100 mg/L phenol solution is achieved within 150 min under visible light irradiation, which is much higher than that in the photocatalytic process of 17.6% or electrochemical process of 19.4%.