Graphdiyne-supported single-cluster electrocatalysts for highly efficient carbon dioxide reduction reaction

The electrochemical CO₂ reduction reaction (CO₂RR) has become a promising technology to resolve globally accelerating CO₂ emissions and produce chemical fuels. In this work, the electrocatalytic performance of transition metal (TM = Cu, Cr, Mn, Co, Ni, Mo, Pt, Rh, Ru and V) triatomic clusters embedded in a graphdiyne (GDY) monolayer (TM₃@GDY) for CO₂RR is investigated by density functional theory (DFT) calculations. The results indicate that Cr₃@GDY possesses the best catalytic performance with a remarkably low rate-limiting step of 0.39 eV toward the CO₂ product, and it can also effectively suppress the hydrogen evolution reaction (HER) during the entire CO₂RR process. Studies on the rate-limiting steps (CHO* + H⁺ + e^- → CHOH) of Cr@GDY (n = 1-4) structures demonstrate that the high catalytic performance is attributed to the strong synergistic reaction of three Cr atoms interacting with the C atom for the Cr₃@GDY structure. The strong synergistic reaction gives rise to the weakest interaction between O-Cr atoms, which leads to the strongest interaction between O-H atoms and makes the hydrogenation process easier for the Cr₃@GDY structure. Furthermore, ab initio molecular dynamics simulations (AIMD) at 500 K reveal the high thermodynamic stability of the Cr₃@GDY structure. These studies may provide a new approach for designing highly efficient electrocatalysts for the CO₂RR under ambient conditions.