Atomically Dispersed Ni-N-C Catalysts for Electrochemical CO2 Reduction.

The atomic dispersion of nickel in Ni-N-C catalysts is key for the selective generation of carbon monoxide through the electrochemical carbon dioxide reduction reaction (CO2RR). Herein, the study reports a highly selective, atomically dispersed Ni1.0%-N-C catalyst with reduced Ni loading compared to previous reports. Extensive materials characterization fails to detect Ni crystalline phases, reveals the highest concentration of atomically dispersed Ni metal, and confirms the presence of the proposed Ni-Nx active site at this reduced loading. The catalyst shows excellent activity and selectivity toward CO generation, with a faradaic efficiency for CO generation (FECO) of 97% and partial current density for CO (jco) of -9.0 mA cm-2 at -0.9 V in an electrochemical H-type cell. CO2RR activity and selectivity are also studied by rotating disk electrode (RDE) measurements where transport limitations can be suppressed. It is expected that the utility of these Ni-N-C catalysts will lie with tandem CO2RR reaction schemes to multi-carbon (C2+) products.