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

Abstract

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 ∼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.