Active sites and reaction mechanisms of CO_x hydrogenation on zinc-based mixed oxide catalysts

The conversion of C1 molecules, CO_x (CO and CO₂), to valuable chemical products has garnered ever-increasing attention. Among many routes, the hydrogenation via thermal catalysis is particularly promising as a key clean energy technology with the increasing supply of green H₂. Zinc-based mixed oxide catalysts exhibit exceptional catalytic performance in the CO_x hydrogenation to value-added hydrocarbons, especially in combination with zeolite. This review overviews the recent achievements in understanding the active sites and reaction mechanisms of CO_x hydrogenation on zinc-based mixed oxide catalysts, focusing on three most-studied zinc-based mixed oxide catalysts, namely ZnCrO_x, ZnAlO_x and ZnZrO_x. The challenges and future directions are also discussed.