Effect of oxygen vacancy on the performance of Ce-promoted CuZn catalysts for ethanol synthesis from syngas

The addition of small amounts of promoters to CuZn catalyst can alter the defect structure of the catalysts and has a significant impact on the catalytic performance. Herein, CuZn catalyst with different oxygen vacancy contents were successfully prepared by introducing Ce via the complete liquid phase method. The results show that Ce promoted the dispersion of Cu, which reduced the grain size of Cu, thus decreasing the generation capacity of low-carbon alkanes. More critically, the addition of Ce can regulate the number of oxygen vacancies, and increased oxygen vacancies enhanced the Cu–Ce interaction and promoted the production of Ce-Ox-Ce species, which favors to enhance the non-dissociative adsorption of CO and improve the selectivity of total alcohols. However, increased oxygen vacancies made a decrease in the values of Cu0/Cu+ and Zn(2−δ)+ species in the catalyst, which are all associated with the formation of the alkyl groups (precursor of ethanol) and the carbon chain growth. Therefore, the optimum value of Ce addition exists, and the CuZn catalyst with the addition of 2.5% Ce achieved excellent catalytic performance with the total alcohol selectivity and the ratios of ethanol reaching 35.0% and 35.0%, respectively. © 2024