Effect of Ni coupling on the photoluminescence property and photocatalytic activity of ZnO nanorods

ZnO nanoparticles are promising UV light driven photocatalyst for the degradation of organic dyes. In this work, we demonstrated that the photocatalytic activity of ZnO nanoparticles could be improved by coupling with Ni particles. The Ni coupled ZnO nanorods were synthesized by two steps solution precipitation method. The surface plasmon resonance stimulated by the defect transition experienced by Ni coupled ZnO nanorods caused quenching of visible emission but enhancing of UV emission in RTPL analysis. The photodegradation of RhB solution in the presence of Ni coupled ZnO nanorods under UV irradiation followed first-order kinetic. The best photodegradation efficiency, i.e. 64% of RhB removal after 90 min UV irradiation with rate constant of 0.0119 min(-1), was achieved when ZnO nanorods coupled with Ni nanoparticles prepared at 0.03 M nickel nitrate were used. The Ni nanoparticles acted as electron traps, pro-longing the charge separation duration. The scavenger test shows that holes and hydroxyl free radical were the dominant reactive species in the photocatalytic degradation of RhB dye by Ni coupled ZnO nanorods under UV irradiation. A refined photodegradation mechanism of RhB dye by Ni coupled ZnO nanorods is proposed based on these findings. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.