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

Electrochemical CO2 reduction reaction (CO2RR) is of importance for reducing global CO2 emissions. Herein, we reported a high active CO2RR catalyst Co-N-Ni/NPCNSs, which is considered as an advanced single-site catalyst with the Co-N-Ni bimetallic sites connected by N bridge between Co and Ni. The N-bridged Co-N-Ni bimetallic sites is confirmed by the X-ray absorption spectroscopy. The Co-N-Ni/NPCNSs catalyst shows higher turnover frequency of 2049 h−1 at low overpotential of 370 mV and CO Faradaic efficiency of 96.4 % than 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. The in-situ synchrotron radiation Fourier transform infrared spectra and the DFT calculations show that N-bridged Co-N-Ni bimetallic sites promoting the formation of COOH* intermediates, thus accelerating CO2RR.