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