CO-Induced Reconstruction of Cu-ZnZrO_x Catalyst Enables Synergistic CO₂/CO Co-Hydrogenation to Methanol

Catalytically active phase depends strongly on reaction conditions. In CO₂ hydrogenation, efforts have largely emphasized CO₂ activation while overlooking how to design active phase for the co-conversion of CO₂ and the kinetically distinct byproduct CO. Here, it is found that adding CO to CO₂-H₂ feeds boosts methanol productivity by up to 2.2-fold via a pronounced synergistic promotion of both CO₂ and CO hydrogenation over a Cu-ZnZrO_x catalyst. In situ spectroscopy reveals that CO accelerates Zn reduction and migration onto Cu, increasing Zn⁰/Cu ratio, Zn²⁺/Cu, and Cu⁺/Cu fraction, while reducing exposed surface Cu from 42% to 19%. This CO-induced restructuring enriches Zn exposure, drives CuZn alloy formation, and creates abundant CuZn alloy-ZnO_x interfaces that stabilize Cu⁺ sites. These interfaces enable a cooperative dual-pathway mechanism: CO₂ is hydrogenated mainly via the formate route at alloy-ZnO_x sites, whereas CO follows the formyl route on Cu sites. Additionally, in situ-formed water accelerates conversion of the rate-determining CH₃O^* intermediate in the CO pathway. Together, CO-driven evolution of active sites, synergistic dual-pathway catalysis, and water-assisted promotion yield highly efficient methanol synthesis from mixed CO-CO₂ feeds.