Enhanced photocatalytic H2 production from glycerol solution over ZnO/ZnS core/shell nanorods prepared by a low temperature route

Abstract

A series of ZnO/ZnS core/shell nanorods with different ZnS/ZnO molar ratios was synthesized via a new water bath route. The nanorods have a diameter of about 100 nm and a length ranging from a few hundred nanometers to several micrometers. They are formed by coating ZnO nanorod with a layer of porous ZnS shell mainly consisting of crystals which are about 12 nm in diameter. The results showed that the deposition thickness of the ZnS shell layer strongly affected the morphologies, surface area, structure, photo absorption and photocatalytic performance of the ZnO/ZnS core/shell nanorods. The as-prepared ZnO/ZnS core/shell nanorods exhibited a higher photocatalytic activity for H2 evolution from the glycerol/water mixtures compared with the ZnO nanorods under the same conditions. The maximum H2 production was 2608.7 and 388.4 μmol h−1 gcat−1 under UV and solar-simulated light irradiation and the corresponding quantum efficiencies were 22% and 13%, respectively. The deposition thickness of the ZnS shell and the interaction between the ZnO rod and ZnS shell and the core/shell structure with n-p heterojunction substantially influence the optical and catalytic performance of the ZnO/ZnS core/shell nanorods.