Cooperated catalytic mechanism of atomically dispersed binary Cu-N4 and Zn-N4 in N-doped carbon materials for promoting electrocatalytic CO2 reduction to CH4

In order to solve the problems of global climate change and energy crisis, one of the greenest and most efficient methods is the resource utilization of CO2. Among them, electrochemical reduction of CO2 (ERC) to CH4 is one of the most promising solutions. It is imperative to explore catalysts with high activity and stability. Herein, a catalyst composed of atomically dispersed binary Cu-Zn sites on a porous N-doped carbon substrate (CuZn-SAs/ NC) is devised to make multi-electron transmission for electro-catalyzing CO2 to CH4 in aqueous media. The Faradaic efficiency (FE) of this catalyst reaches up to 84.7% and a partial current density (at -1.1 V vs. RHE) is about -49.7 mA cm-2, which is superior to single Cu or Zn counterparts. Moreover, after 45 h of ERC, there is no significant attenuation for the current density and FE, suggesting its remarkable stability. Theoretical calculations further indicate that uniformly atomically dispersed Cu-Zn sites and synergistic action of Cu and Zn active centers have substantially impeded CO production and largely accelerated CH4 generation.