High-yield ethanol production via thermocatalytic CO2 hydrogenation over Cs/CuZnFe catalyst in a continuous flow reactor

Achieving high ethanol yield and catalyst stability in CO 2 hydrogenation presents a significant scientific and technological challenge, which can be addressed through advanced catalyst design. Hence, in this work, we present the findings of our research on a Cs/CuZnFe active catalyst, which demonstrates effective and selective synthesis of C 2+ alcohols (78.8 mol%) through CO 2 hydrogenation with corresponding conversion of 17.0 %. The optimized catalyst, denoted as 4%Cs/25%Cu − 25%Zn − 50%Fe, displays a remarkable space time yield (STY) of ethanol = 5.0 mmol·g cat −1 ·h −1 in the gas phase at 300 °C under 20 bar with H 2 /CO 2 = 3 and GHSV = 9917 h −1 . The catalyst exhibits a high level of performance relative to most comparable systems in the literature. The exceptional catalytic activity is mainly due to the catalyst large pore diameter, significant crystallite size, excellent crystallinity, high oxygen vacancies, and low basicity. Additionally, the 4%Cs loading provides a stabilizing effect by preventing Cu loss and maintaining an optimal balance between low basicity and high oxygen vacancies, enhancing CO 2 activation while minimizing excessive adsorption and side product formation. Finally, our investigation into the mechanism reveals that the reaction follows a tandem pathway involving both CO insertion and the formate pathway, with the latter predominating. • An efficient Cs/CuZnFe catalyst for CO 2 hydrogenation to EtOH was developed. • CO 2 conversion of 17.0 % and C 2+ alcohols selectivity of 78.8 % were achieved. • The space time yield of ethanol reaches 5.0 mmol·g cat −1 ·h −1 at 300 °C. • High PD, crystallinity, oxygen vacancies, and low basicity enhance activity. • The reaction follows a tandem CO insertion and formate pathway for EtOH.