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 Ni_1.0%-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-N_x active site at this reduced loading. The catalyst shows excellent activity and selectivity toward CO generation, with a faradaic efficiency for CO generation (FE_CO) of 97% and partial current density for CO (j_co) 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.