Branch-like ZnS–DETA/CdS hierarchical heterostructures as an efficient photocatalyst for visible light CO2 reduction

Abstract

Exploring high-efficiency photocatalysts for CO₂ reduction is highly desirable in view of the current energy and environmental crisis. Herein, we present the design and synthesis of branch-like ZnS–DETA/CdS (DETA = diethylenetriamine) hierarchical heterostructures assembled from ultrathin nanowires for efficient photocatalytic CO₂ reduction under visible light. With ZnS–DETA nanosheets as a precursor, the ZnS–DETA/CdS hierarchical hybrids are readily achieved through a cation-exchange approach, leading to the formation of uniformly distributed heterojunctions in nanodomains and controllable compositions. The systematic physicochemical characterizations reveal that the ZnS–DETA/CdS heterostructures can effectively absorb the visible light, offer large surface area and abundant active sites for CO₂ adsorption and surface reactions, and expedite separation and transport of charge carriers. The ZnS–DETA/CdS photocatalyst shows the highest CO generation rate of 33.3 μmol h⁻¹ (i.e., 8325 μmol h⁻¹ g⁻¹) for deoxygenative CO₂ reduction. Moreover, the photocatalyst also exhibits high stability and good reusability for the CO₂ reduction reaction. In addition, a possible photocatalytic CO₂ reduction mechanism over the ZnS–DETA/CdS heterostructure is proposed.