Abstract: CO₂ hydrogenation to ethanol offers the dual benefit of achieving carbon neutrality and addressing energy crises. However, its complex multi-step reaction mechanism imposes stringent requirements on catalyst design. Conventional bimetallic catalysts are limited by issues such as easy agglomeration of active components, low specific surface area due to dense particle structures, and poor interfacial tunability. In this study, hollow flower-like bimetallic Cu-Co was prepared via a solvothermal method, and mechanically mixed with spinel-phase ZnFeO_x to develop a Cu-Co/ZnFeO_x composite catalyst. Cu-Co/ZnFeO_x catalyst features a hierarchical hollow structure with abundant mesoporous networks and a high specific surface area. Under reaction conditions of H₂ : CO₂=3 : 1 (in volume), gas hourly space velocity (GHSV)=12000 mL/(g_cat·h), 300 ℃ and 1.5 MPa, Cu-Co/ZnFeO_x catalyst increases CO₂ conversion from 16.9% to 21.4% compared to Cu-Co alone, raises the selectivity of higher alcohols (C₂₊OH) from 17.0% to 26.7%, and achieves an ethanol selectivity of 61.8% in C₂₊OH. The hollow flower-like Cu-Co framework provides efficient mass transfer pathways and abundant H₂ activation sites, while ZnFeO_x offers high CO₂ adsorption and activation capability. The strong electronic coupling between Cu-Co and ZnFeO_x synergistically promotes the H₂ dissociation and CO₂ activation. The underlying electronic synergy mechanism reveals strong metal-support interactions between the Cu-Co bimetallic and ZnFeO_x. This synergistic effect promotes the formation of intermediates (CH_x*) and C-C coupling, facilitating the formation and stabilization of key intermediates such as CH₃CO* and CH₃CH₂O*, thereby enabling efficient and highly selective ethanol production. This study provides a reference for designing efficient, stable, and low-cost catalysts for CO₂ hydrogenation.

Key words: CO₂ hydrogenation, ethanol, Cu-Co, ZnFeO_x