Electron Tug Effect in Ni Single Atoms for Carbon Dioxide Electroreduction over a Wide Potential Range

Abstract

Atomically dispersed symmetrical NiN4 moieties represent a promising category of catalysts for electrochemical reduction of carbon dioxide (eCO2RR). Nonetheless, their practical application is constrained by challenges such as high overpotentials and limited potential ranges. Here, we report Ni active sites with unique electron distribution realized by minute amounts of Au nanoparticles decoration and lateral oxygen coordination (Au/Ni-N-O-C) for achieving a low overpotential while widening the applied potential ranges. The optimized Au0.5/Ni-N-O-C catalyst exhibits an outstanding eCO2RR performance, achieving over 95% Faradaic efficiency (FE) of CO within a broad potential window from −0.50 to −0.85 V vs. reversible hydrogen electrode, notably, 93% FECO at an overpotential of 340 mV. Theoretical calculations demonstrate that additional electron tug effect on Ni single atoms, induced by the oxygen in the lateral coordination configuration and introduced Au nanoparticles, effectively lower the free energy for *COOH formation by redistributing the electronic distribution of Ni active sites, thus significantly promoting the eCO2RR across a wide applied potential range. This strategy not only presents an efficient pathway to regulate the electron distribution of single atom catalysts, but also is potentially adaptable for diverse catalytic reactions.