Modulating CO₂ Electroreduction on Dual-Atom Catalysts through Orbital Interactions

The electrochemical CO₂ reduction reaction (CO₂RR) efficiency and selectivity are limited by the high stability of the CO₂ molecules and the complexity of the reaction pathways. We herein investigated the geometric configuration, orbital interaction, and spin states of Fe/Co dual-atom catalysts (DACs) that regulate the CO₂RR mechanism by using density functional theory calculations. It is demonstrated that the spatial structure and orientation of frontier orbitals of DACs determine both the CO₂ physisorption/chemisorption behavior and the following reaction pathway as well as product selectivity. Notably, the spin engineering effectively manipulates d-orbital energy splitting, thereby altering the rate-limiting step and reducing the limiting potential of CO₂RR. Furthermore, the manipulation of the spin state of metals in DACs results in a clear volcano-type relationship between dual-metal d_yz+z²+xz orbitally resolved energy level and the rate-limiting potential in CO₂RR. This work provides an atomic-scale theoretical framework for the rational design of efficient dual-atom catalysts for CO₂RR.