Cu–Zn Synergy for CO Hydrogenation to Ethanol and Methanol on CuZnO Catalysts

Catalysts with different Cu/Zn ratios were prepared by the complete liquid-phase method, and their catalytic CO hydrogenation performance was investigated at slurry bed. Their physicochemical properties were characterized by XRD, BET, H2-TPR, and XPS. The results show that Cu1.0Zn1.0 catalyst had higher ethanol selectivity and Cu1.0Zn3.0 catalyst had higher CO conversion and methanol selectivity. It was found that the number of Cu+ sites plays a crucial role in the syngas conversion. More surface Cu+ content is favorable to ethanol synthesis, while less surface Cu+ content is favorable to methanol synthesis. In addition, more oxygen vacancies are conducive to the generation of stronger Cu–Zn interaction, which is beneficial to ethanol selectivity. It is further indicated that there was a synergy of Cu0, Cu+, and ZnOx on the catalyst surface.Graphic Abstract