Nanostructures inducing distinctive photocatalytic and photoelectrochemical performance via the introduction of rGO into CdxZn1−xS

Abstract

It is well known that efficient charge separation is a crucial factor for the enhancement of photocatalytic activity for hydrogen evolution, and the internal electric field is commonly designed to improve charge separation. The microstructure of a catalyst has a significant effect on the photocatalytic and photoelectrochemical (PEC) performance. Herein, two samples are engineered with similar morphology but different crystal structures. Small wurtzite (WZ)/zinc blende (ZB) -Cd_0.6Zn_0.4S nanorods are featured with dense type-II homojunctions. By utilizing the excellent thermal conductivity of graphene to eliminate thermal fluctuations, WZ-Cd_0.6Zn_0.4S/RGO is obtained by anchoring Cd_0.6Zn_0.4S nanorods on the graphene sheets. The elongated WZ/ZB-Cd_0.6Zn_0.4S nanorods with an internal electric field formed by the heterophase homojunction greatly improve the photocatalytic hydrogen production rate to 36.33 mmol h⁻¹ g⁻¹, much higher than that of WZ-Cd_0.6Zn_0.4S-RGO. On the contrary, WZ-Cd_0.6Zn_0.4S/RGO shows superior photoelectrochemical performance under an external electric field, benefiting from the excellent electric conduction and the 2D network of RGO as electron transportation channels. The study strategy and synthetic route for the Cd_0.6Zn_0.4S nanorods with a homojunction and a homogenous structure in our work may open up new avenues for the fabrication of other semiconductor materials with distinctive photocatalytic and PEC applications.