The electrochemical reduction of CO₂ is an extremely potential technique to achieve the goal of carbon neutrality, but the development of electrocatalysts with high activity, excellent product selectivity, and long-term durability remains a great challenge. Herein, the role of metal-supports interaction (MSI) between different active sites (including single and bimetallic atom sites consisting of Cu and Ni atoms) and carbon-based supports (including C₂N, C₃N₄, N-coordination graphene, and graphdiyne) on catalytic activity, product selectivity, and thermodynamic stability towards CO₂ reduction reaction (CRR) is systematically investigated by first principles calculations. Our results show that MSI is mainly related to the charge transfer behavior from metal sites to supports, and different MSI leads to diverse magnetic moments and d-band centers. Subsequently, the adsorption and catalytic performance can be efficiently improved by tuning MSI. Notably, the bimetallic atom supported graphdiyne not only exhibits a better catalytic activity, higher product selectivity, and higher thermodynamic stability, but also effectively inhibits the hydrogen evolution reaction. This finding provides a new research idea and optimization strategy for the rational design of high-efficiency CRR catalysts.

Linear relations between the adsorption free energies of nitrogen reduction reaction (NRR) intermediates limit the catalytic activity of single atom catalysts (SACs) to reach the optimal region. Significant improvements in NRR activity require the balance of binding strength of reaction intermediates. Herein, we have investigated the C₃N-supported monometallic (M/C₃N) and bimetallic (M₁M₂/C₃N) atoms for the electrochemical NRR by using density functional theory (DFT) calculations. The results show that this linear relation does exist for SACs because all the intermediates bind to the same site on M/C₃N. But the synergistic effect of the two atoms in M₁M₂/C₃N can create a more flexible adsorption site for intermediates, which results in the decoupling of adsorption free energies of key intermediates. Subsequently, the fundamental limitation of scaling relations on limiting potentials is broken through. Most notably, the optimal limiting potential is increased from −0.63 V for M/C₃N to −0.20 V for M₁M₂/C₃N. In addition, the presence of bimetallic atoms can also effectively inhibit the hydrogen evolution reaction (HER) as well as improve the stability of the catalysts. This study proposes that the introduction of bimetallic atoms into C₃N is beneficial to break the linear relations and develop efficient NRR electrocatalysts.