Enhanced CO2 Electroreduction by Stabilizing *COOH on Ni Single Atoms via Short- and Long-Range Electronic Modulation

Abstract

Ni single-atoms (SAs) are active for electrocatalytic CO₂ reduction reaction (CO₂RR) to CO, but their performance still needs to be further improved for practical implementation. Herein, a strategy of “short- and long-range modulation” is reported to synergistically modulate the electronic structure of Ni SAs by constructing Ni nanoparticles (NPs) integrated with N, P-coordinated Ni SAs on N-doped carbon supports (Ni-P₁N₃/Ni_NPs@NC). Experiments and theoretical calculations reveal that both the short-range modulation involving Ni–P coordination and the long-range modulation by Ni NPs collectively enhance the electron localization around Ni SAs, thus increasing the binding strength for the key ^*COOH intermediate. This results in an improved CO₂RR performance of Ni SAs by lowering the energy barrier. Ni-P₁N₃/Ni_NPs@NC exhibits a Faradaic efficiency for CO exceeding 99.0% across a wide potential range from −0.5 to −1.1 V versus reversible hydrogen electrode (vs RHE), with the highest partial current density for CO of −544 mA cm⁻² at −1.1 V vs RHE.