Surface Plasmonic Resonance and Z-Scheme Charge Transport Synergy in Three-Dimensional Flower-like Ag-CeO2-ZnO Heterostructures for Highly Improved Photocatalytic CO2 Reduction

The design and engineering of plasmonic metal nanocomposite photocatalysts offer an operative approach for highly efficient CO2 photoreduction. Herein, the authors report a plasmonic 3D flower-like (3DF) Ag-CeO2-ZnO nanocomposite catalyst with effective charge carrier separation/transfer and CO2 adsorption capacity exhibiting a considerable enhanced performance compared to pure ZnO and CeO2 for photocatalytic CO2 reduction to CO and CH4 under UV-vis light. The apparent quantum efficiency of the optimized sample is 4.47% at 420 nm, and the CO2 to CO selectivity reaches up to similar to 95%. The enhanced photocatalytic performance of 3DF Ag-CeO2-ZnO can be assigned to the prolonged absorption in the visible light region induced by the surface plasmon resonance (SPR) effect, the efficient separation of photogenerated charges, and the Z-scheme configuration. Furthermore, the photocatalyst displays excellent stability and reusability. The mechanism of the plasmon-mediated Z-scheme structure has been suggested in which Ag NPs act as both visible light absorber and electron mediator.