Construction of hierarchical Ag@TiO2@ZnO nanowires with high photocatalytic activity†
Abstract
Noble metal loading and semiconductor compositing are two effective techniques to improve the photocatalytic activity of semiconductor photocatalysts. These two tactics are combined herein to achieve hierarchical Ag@TiO2@ZnO nanowires, which consist of ZnO nanorods growing radially from Ag nanowires with the help of a compact TiO2 intermediate layer. The Ag@TiO2@ZnO nanowires consisted of 4.3 wt% Ag, 16.7 wt% TiO2 and 79.0 wt% ZnO. When utilized to assist photodegradation of phenol in water under UV light illumination, the nanowires exhibited a reaction rate constant 1.8 times that of commercial Degussa P25 TiO2 nanoparticles and 3.8 times that of commercial ZnO nanoparticles. The excellent photocatalytic activity can be contributed to the enhanced light adsorption and charge separations arising from both Ag/TiO2 Schottky barriers and TiO2/ZnO heterojunctions.