High selectivity and abundant active sites in atomically dispersed TM2C12 monolayer for CO2 reduction

Developing highly efficient single-atom catalysts (SACs) for electrocatalytic carbon dioxide reduction reaction (CO₂RR) is a promising approach to promoting carbon neutrality. However, challenges such as low activity, selectivity and high costs hinder industrial scaling, attributed to the lack of innate activity or insufficient transition metal (TM) active site density in current catalysts. Therefore, the focus of CO₂RR research remains on developing SACs with intrinsic catalytic activity, high TM coverage and cost-effectiveness. This study presents the design of carbon-based materials with ultra-high TM coverage (TM₂C₁₂) (TM = Mo, Ru, Rh, W, Re, Os and Ir) as electrocatalyst SACs for CO₂RR using density functional theory calculations. Among these materials, W₂C₁₂ (W represents tungsten) demonstrates superior selectivity and catalytic activity for CO₂RR to carbon monoxide (CO) products with overpotentials of 0.45 V and a W coverage of up to 71.84 wt%. To further enhance its catalytic activity, non-metallic (NM) coordination modification (NM = B, N, O, P doping and C vacancy) was explored on W₂C₁₂. The results indicate that N-doped W₂C₁₂ (N-W₂C₁₂) can significantly improve selectivity and catalytic activity, achieving an extremely low overpotential of 0.34 V. This research offers valuable insights into designing SACs with high activity, selectivity and stability for CO₂RR and other catalytic reactions.