Non-Interacting Ni and Fe Dual-Atom Pair Sites in N-Doped Carbon Catalysts for Efficient Concentrating Solar-Driven...

Solar-to-chemical energy conversion under weak solar irradiation is generally difficult to meet the heat demand of CO₂ reduction. Herein, a new concentrated solar-driven photothermal system coupling a dual-metal single-atom catalyst (DSAC) with adjacent Ni-N₄ and Fe-N₄ pair sites is designed for boosting gas-solid CO₂ reduction with H₂ O under simulated solar irradiation, even under ambient sunlight. As expected, the (Ni, Fe)-N-C DSAC exhibits a superior photothermal catalytic performance for CO₂ reduction to CO (86.16 μmol g^-1  h^-1 ), CH₄ (135.35 μmol g^-1  h^-1 ) and CH₃ OH (59.81 μmol g^-1  h^-1 ), which are equivalent to 1.70-fold, 1.27-fold and 1.23-fold higher than those of the Fe-N-C catalyst, respectively. Based on theoretical simulations, the Fermi level and d-band center of Fe atom is efficiently regulated in non-interacting Ni and Fe dual-atom pair sites with electronic interaction through electron orbital hybridization on (Ni, Fe)-N-C DSAC. Crucially, the distance between adjacent Ni and Fe atoms of the Ni-N-N-Fe configuration means that the additional Ni atom as a new active site contributes to the main *COOH and *HCO₃ dissociation to optimize the corresponding energy barriers in the reaction process, leading to specific dual reaction pathways (COOH and HCO₃ pathways) for solar-driven photothermal CO₂ reduction to initial CO production.