NiSn Atomic Pair on an Integrated Electrode for Synergistic Electrocatalytic CO₂ Reduction

The development of efficient electrocatalysts for the CO₂ reduction reaction (CO₂ RR) remains a challenge. Demonstrated here is a NiSn atomic-pair electrocatalyst (NiSn-APC) on a hierarchical integrated electrode, which exhibits a synergistic effect in simultaneously promoting the activity and selectivity of the CO₂ RR to formate. The NiSn atomic pair consists of adjacent Ni and Sn, each coordinated with four nitrogen atoms (N₄ -Ni-Sn-N₄ ). The as-prepared NiSn-APC displays exceptional activity for the CO₂ RR to formate with a turnover frequency of 4752 h^-1 , a formate productivity of 36.7 mol h^-1  g_Sn ^-1 and an utilization degree of active sites (57.9 %), which are superior to previously reported single-atomic catalysts. Both experimental data and density-functional theory calculations verify the electron redistribution of Sn imposed by adjacent Ni, which reduces the energy barrier of the *OCHO intermediate and makes this potential-determining step thermodynamically spontaneous. This synergistic catalysis provides a successful paradigm for rational design and preparation of atomic-pair electrocatalysts with enhanced performance.