Computational screening of high activity and selectivity of CO₂ reduction via transition metal single-atom catalysts on triazine-based graphite carbon nitride

Single-atom catalysts (SACs) are emerging as promising catalysts in the field of the electrocatalytic CO₂ reduction reaction (CO₂RR). Herein, a series of 3d to 5d transition metal atoms supported on triazine-based graphite carbon nitride (TM@TGCN) as a CO₂ reduction catalyst are studied via density functional theory computations. Eventually, four TM@TGCN catalysts (TM = Ni, Rh, Os, and Ir) are selected using a five-step screening method, in which Rh@TGCN and Ni@TGCN show a low limiting potential of -0.48 and -0.58 V, respectively, for reducing CO₂ to CH₄. The activity mechanism shows that the catalysts with a negative d-band center and optimal positive charge can improve the CO₂RR performance. Our study provides theoretical guidance for the rational design of highly active and selective catalysts.