Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties

Abstract

A series of Zn1−xCoxO nanorods with dopant content ranging fromx = 0.00 to 0.10 was prepared by a wet chemical method. AllZn1−xCoxO samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersionx-ray line mapping analysis, and UV–visible absorption spectroscopy. It was found thatCo2+ ions were homogeneouslysubstituted for Zn2+ ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effectof Co2+ doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation.Co2+ ions acted as the trapping or recombination centers for electrons and holes, leading to areduction in photodegradation efficiency under UV light illumination. Alternatively,Co2+ ions enhanced the optical absorption and produced the photoinduced carriersunder visible illumination in terms of two charge transfer transitions involvingCo2+ ions.Consequently, Co2+ ions substituted in the lattice of ZnO nanorods significantly improved the visible lightphotocatalytic activity.