Catalytic mechanisms of dual atom catalysts to facilitate electroreduction of carbon dioxide

The electrochemical reduction of carbon dioxide (CO2RR) offers a sustainable strategy for achieving carbon cycling and sustainable fuel production, yet its efficiency and product selectivity are strongly governed by catalyst design. Dual-atom catalysts (DACs) have recently gained significant attention due to their synergistic bimetallic interactions, tunable electronic structures, and ability to surpass the scaling limitations of single-atom catalysts, exhibiting great potential to improve the activity and selectivity of CO2RR by more efficient CO2 activation, stabilization of key intermediates, and promotion of C-C coupling toward multi-carbon products. Therefore, this review systematically summarizes the latest advances of dual-atom catalysts in catalyzing CO2RR, with a focus on clarifying their catalytic mechanisms and structure-activity relationships. We start by outlining the fundamental reaction pathways of CO2RR, covering C1, C2 and C3 products formation through key steps including CO2 adsorption, CO2 activation, intermediate evolution, and C-C coupling. Subsequently, we discuss the catalytic principles of DACs across three mechanisms, i.e., single active site mode where one site serves as the primary active center, co-active site mode where bimetallic sites cooperatively adsorb reaction intermediates, and cascade active site mode where dual sites guide sequential reaction steps. We then summarize the recent progress in developing homonuclear and heteronuclear DACs for CO2RR, with emphasis on the influence of structural parameters such as metal atom type, coordination environment and atomic distance on catalytic performance. Remaining challenges and future opportunities are also discussed to guide the rational design of next-generation DACs for efficient CO2RR.