Local compressive strain regulation of atomically dispersed NiN sites for enhancing CO electroreduction to CO.

Electroreduction of CO to valuable chemicals powered by renewable electricity provides a sustainable approach to reduce the environmental issues originating from CO emission. However, insufficient current density and production selectivity hinder its further application. In this case, precisely regulating the CO reduction reaction (CORR) active sites is an excellent strategy to simultaneously reduce the reaction barrier and suppress the hydrogen evolution reaction (HER) pathway. Herein, the strain regulation of atomically dispersed NiN active sites is investigated in helical carbon. Ni-N coordination in the curved carbon lattice displays a reduced distance compared to that in a straight lattice, inflicting local compressive strain on NiN. The resultant catalyst shows the highest CO selectivity of up to 99.4% at -1.4 V ( RHE), the FE is maintained at over 85% over a wide potential range from -0.8 to -1.8 V ( RHE), and the maximum partial current density for CO reaches a high of 458 mA cm at -1.8 V ( RHE). Theoretical investigations show the superior CO electroreduction performance of curved NiN stems from its remarkable ability to generate the *COOH intermediate and to suppress the hydrogen combination simultaneously. Our findings offer a novel strategy to rationally regulate the local three-dimensional structure of single-atom sites for efficient electrocatalysis.