Enhanced photocatalytic activity of Ce-doped ZnO nanorods under UV and visible light

Ce-doped ZnO nanorod photocatalysts with high visible light-driven activity were synthesized by a hydrothermal process. Effects of doping on the adsorption ability, band gap modification, surface chemistry, separation of electron-hole pairs, and photocatalytic activity of ZnO photocatalysts were investigated by combining the diffuse reflectance spectra, photoelectrochemical scanning electrochemical microscopy (PEC-SECM), and X-ray photoelectron spectroscopy (XPS) analysis. The mechanism of cerium ion doping induced photocatalytic activity enhancement was proposed and evaluated by studying the degradation performances in the presence of different scavengers. Introducing an appropriate amount of Ce ion dopant can enhance the photocatalytic activity, which can be attributed from the increased surface oxygen vacancies, higher adsorption capacity and better separation of electron-hole pairs in nanostructured photocatalyst. Excess concentration of dopant precursor leads to the formation of cerium oxide aggregates around the nanorods and deteriorated photocatalytic activity. The optimized photocatalyst shows almost no activity loss after three repeated degradation experiments. (C) 2014 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.