Progress in unraveling the mechanisms of dual functional materials for CO2 capture and reduction

Carbon dioxide (CO 2 ) capture and hydrogenation reduction (CCR) offers a promising route to reduce greenhouse gas emissions while converting CO 2 into value-added chemicals, contributing to carbon-neutral strategies. Dual functional materials (DFMs), which could simultaneously achieve CO 2 capture and in-situ hydrogenation conversion in a single material system, have therefore attracted growing attention. Nevertheless, the complex reaction pathways, multiple intermediates, and parallel networks involved in CO 2 hydrogenation led to highly diverse and intricate catalytic mechanisms over DFMs. This review summarizes recent advances in DFMs for CCR, focusing on key hydrogenation pathways to CO, CH 4 , and CH 3 OH and the evolution of associated intermediates. Advanced in-situ /operando characterization techniques and density functional theory calculations are highlighted for their roles in elucidating reaction mechanisms and metal-adsorbent synergistic effects. DFMs are further classified by active metal type, with representative Ni-, Ru-, Cu-, and Fe-based systems critically reviewed to highlight synergistic interactions among active metals, adsorbents, promoters, and supports, as well as rational structural design strategies for mitigating sintering and deactivation. Overall, this review provides mechanistic insights and design principles to guide the development of efficient, low-energy, and industrially viable DFMs for CCR reactions.