N-Bridged Co–N–Ni: new bimetallic sites for promoting electrochemical CO2 reduction

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) is of importance for reducing global CO₂ emissions. Herein, we reported a highly active CO₂RR catalyst, namely Co–N–Ni/NPCNSs, which is considered as an advanced single-site catalyst with Co–N–Ni bimetallic sites connected by a N bridge between Co and Ni. The N-bridged Co–N–Ni bimetallic sites were confirmed by the X-ray absorption spectroscopy. The Co–N–Ni/NPCNSs catalyst shows a higher turnover frequency of 2049 h⁻¹ at a low overpotential of 370 mV and CO faradaic efficiency of 96.4% compared to that of Co–N/NPCNSs (1205 h⁻¹ and 61.5%) and Ni–N/NPCNSs (404 h⁻¹ and 45.0%) with single Co–N₄ and Ni–N₄ sites, respectively. In situ synchrotron radiation Fourier transform infrared spectra and DFT calculations show that N-bridged Co–N–Ni bimetallic sites promote the formation of COOH* intermediates, thus accelerating CO₂RR.