Understanding the role of metal and N species in M@NC catalysts for electrochemical CO2 reduction reaction

The electrochemical CO2 reduction reaction (CO2RR) that transforms CO2 to CO has attracted great interest. Transition metal nanoparticles encapsulated in nitrogen-doped carbon (M@NC) catalysts exhibit outstanding catalytic performance. However, the role of metal and N species in M@NC catalysts remains unclear. In this work, Co@C, Co@NC, Ni@C, and Ni@NC catalysts were achieved and employed in CO2RR. The Ni@NC catalyst exhibits an industry level current density of 220 mA cm(-2) and a high Faradaic efficiency of 98% for CO production at -0.87 V vs. RHE for 100 h. In addition, the N species, especially the pyrrolic-N in the shell of Ni@NC material provide active sites for adsorbing and activating CO2 molecules, and metal nanoparticles improve the electronic structure of N species, thereby decreasing their ability for radical attack (*COOH, *CO, and *H). Consequently, this work can guide the design of M@NC catalyst for CO2RR to CO.& nbsp;