The Specific Functionality of Pd-Ag Heteronuclear Dual-atom Catalysts for Efficient Photocatalytic CO₂ Reduction

Precisely constructing photocatalysts with dual-atom sites to simultaneously enhance both photocatalytic activity and dual-atom stability presents a formidable challenge, as these two processes follow distinct pathways. This study synthesized a Pd-Ag heteronuclear dual-atom (DA) catalyst anchored on nitrogen-doped graphene (CN) utilizing a high-temperature reduction method (PdAg/CN-DA). The catalyst demonstrated remarkable photocatalytic activity in the CO₂ reduction reaction (CO₂RR), achieving an average CO production rate of 816.6 µmol·g^-1·h^-1 during the CO₂RR, exhibiting good stability and selectivity. After conducting four cycling tests, the catalytic activity showed no significant decline, and the selectivity reached an impressive 98.10%. Both experimental and theoretical calculations indicate that the Pd-Ag diatomic system demonstrates an elevated density of electronic states at the Fermi level, which significantly lowers the energy barrier for electron transfer during interactions with reaction intermediates, particularly in the rate-determining step (^*CO₂→^*COOH). Furthermore, the introduced Ag species stabilizes the Pd active sites by enhancing the stability of the Pd─N bond, thereby preventing aggregation and deactivation. The superior catalytic performance, exceptional stability, and cost-effectiveness of the catalyst presented in this work provide a novel pathway for the design of efficient photocatalysts.