Cascaded electron transition in CuWO4/CdS/CDs heterostructure accelerating charge separation towards enhanced photocatalytic activity

A cascaded electron transition pathway was presented in a ternary heterostructure consisting of CdS quantum dots, carbon dots (CDs) and CuWO4 hollow spheres, which greatly facilitates the photogenerated electron-hole separation and eventually boosts the degradation efficiency of phenol and congo red by 100% and 46% compared to bare CuWO4. [Display omitted] CuWO4, as an n-type oxide semiconductor with a bandgap of 2.2 eV, has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations. However, rapid charge recombination greatly hinders its practical applications. Herein, we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots, carbon dots (CDs) and CuWO4 hollow spheres, which proves to greatly facilitate the photogenerated electron-hole separation, and eventually boosts the degradation efficiency of phenol and congo red by 100% and 46% compared to bare CuWO4. The enhanced performance of the CuWO4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO4 and then to the organics through CDs. This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO4 based photocatalysts.