Palladium single atoms: engineering asymmetric active sites for selective photothermal reduction of carbon dioxide to...

Photothermal (PT) synergistic catalysis for the conversion of CO₂ to methanol (MeOH) represents a promising strategy for CO₂ utilization. However, the development of Cu-ZnO catalysts exhibiting high thermal stability and photocatalytic activity remains a critical challenge for efficient CO₂ conversion via the PT catalysis. To address these issues, Pd single atoms are successfully anchored onto the Cu-ZnO surface of the Z-scheme heterostructure (designated as Pd₁/Cu-ZnO), resulting in three distinct asymmetric coordination environments: Pd-O-Cu, Pd-Cu, and Pd-O-Zn. The non-uniform charge distribution at the Pd-Cu site on Pd₁/Cu-ZnO enhances the adsorption and dissociation of H₂, while the Pd-O-Zn site simultaneously optimizes the CO₂ adsorption configuration, thereby promoting significant elongation of the C=O bond. The band structures of semiconductors (CuO and ZnO) are modulated by Pd single atoms, which simultaneously enhances the localized surface plasmon resonance (LSPR) effect for Cu⁰, thereby improving Pd₁/Cu-ZnO light response. The MeOH yield achieved with Pd₁/Cu-ZnO as the catalyst is 1.45 times greater in the PT catalytic reaction compared to the thermal catalytic reaction, reaching 332.1 mmol·g^-1Cu·h^-1, while the selectivity increased from 50.1% to 87.2%, highlighting the exceptional performance of the single atom asymmetric sites. This study underscores the crucial role of single atoms in PT synergistic catalysis, demonstrating their superior potential for enhancing CO₂ utilization under mild conditions and improving atomic economy.