ZnO/ZnS heterostructured nanorod arrays and their efficient photocatalytic hydrogen evolution.

Abstract

Semiconducting heterostructures have been widely applied in photocatalytic hydrogen evolution due to their variable band gaps and high energy conversion efficiency. As typical semiconducting heterostructures, ZnO/ZnS heterostructured nanorod arrays (HNRAs) have been obtained through a simple anion-exchange process in this work. Structural characterization indicates that the heterostructured nanorods (HNRs) are all composed of hexagonal wurtzite ZnO core and cubic zinc-blende ZnS shell. As expected, the as-obtained one-dimensional heterostructures not only lower the energy barrier but also enhance the separation ability of photogenerated carriers in photocatalytic hydrogen evolution. Through comparisons, it is found that 1D ZnO/ZnS HNRAs exhibit much better performance in photocatalytic hydrogen evolution than 1D ZnO nanorod arrays (NRAs) and 1D ZnS NRAs. The maximum H2 production is 19.2 mmol h(-1) for 0.05 g catalyst under solar-simulated light irradiation at 25 °C and the corresponding quantum efficiency is 13.9 %, which goes beyond the economical threshold of photocatalytic hydrogen evolution technology.