Construction of CuO quantum Dots/WO3 nanosheets 0D/2D Z-scheme heterojunction with enhanced photocatalytic CO2 reduction activity under visible-light

Construction of Z-scheme heterojunction has received more attention in photocatalytic CO2 reduction owing to its excellent charge carriers separation efficiency and unweakened redox capability of different active components. Herein, a novel CuO quantum dots (QDs)/WO3 nanosheets (NSs) 0D/2D Z-scheme heterojunction was synthesized by a self-assembly method. The CuO QDs with an average diameter of 1.6 nm are uniformly distributed on the WO3 NSs, affording a close interface and short charge diffusion distance, which can effectively promote the separation efficiency of charge carriers. Moreover, the Z-scheme charge transfer mechanism simultaneously keeps the strong reduction capability of CuO and oxidation of WO3, thus enhancing the photocatalytic CO2 reduction performance. Resulting from the 0D/2D structural benefits and Z-scheme charge transfer mechanism, the CuO QDs/WO3 NSs performs a much higher photocatalytic activity by reducing CO2 with H2O vapor into CO under visible-light irradiation, which is significantly higher than those of pure CuO and WO3. This study constructs a novel Z-scheme heterostructure by combining different narrow-bandgap semiconductors, which can possess a rapid charge transfer rate and superior redox ability in CO2 photoreduction.