Interatomic Electronegativity Offset Dictates Selectivity When Catalyzing the CO2 Reduction Reaction

Achieving efficient efficiency and selectivity for the electroreduction of CO2 to value-added feedstocks has been challenging, due to the thermodynamic stability of CO2 molecules and the competing hydrogen evolution reaction. Herein, a dual-single-atom catalyst consisting of atomically dispersed CuN4 and NiN4 bimetal sites is synthesized with electrospun carbon nanofibers (CuNi-DSA/CNFs). Theoretical and experimental studies reveal the strong electron interactions induced by the electronegativity offset between the Cu and Ni atoms. The delicately averaged and compensated electronic structures result in an offset effect that optimizes the adsorption strength of the *COOH intermediate and boosts the CO2 reduction reaction (CO2RR) kinetics, notably promoting the intrinsic activity and selectivity of the catalyst. The CuNi-DSA/CNFs catalyst exhibits an outstanding FECO of 99.6% across a broad potential window of -0.78- -1.18 V (vs the reversible hydrogen electrode), a high turnover frequency of 2870 h(-1), and excellent durability (25 h). Furthermore, an aqueous Zn-CO2 battery for CO2 power conversion is constructed. This atomic-level electronegativity offset of the dual-atom structures provides an appealing direction to develop advanced electrocatalysts for the CO2RR.