Water-Promoted C–C Coupling Reaction in Plasma-Catalytic CO<sub>2</sub> Hydrogenation for Ethanol Production
Shengyan Meng, Zhaolun Cui, Qian Chen, Hang Zhang, Shangkun Li, Erik C. Neyts, Evgenii Vlasov, Kellie Jenkinson, Sara Bals, Dezheng Yang, Min Liu, Yi Liu, Annemie Bogaerts, An‐Hui Lu, Yanhui Yi
Abstract
The conversion of CO 2 into alcohols has attracted widespread interest. Herein, we present an approach for the plasma-catalytic CO 2 hydrogenation to ethanol over a Cu 2 O/CeO 2 catalyst under atmospheric pressure at a low temperature of ∼75 °C. The Cu 2 O/CeO 2 catalyst initially exhibits low ethanol selectivity (2.1%), which dramatically increases to 56% (78% total alcohols selectivity) with the assistance of water. D 2 O and H 2 18 O isotope-tracing experiments reveal the partial decomposition of water and the active involvement of its derivatives in the multistep pathway for ethanol synthesis. The multiple roles of H 2 O in switching alcohols production from methanol to ethanol are investigated. The plasma-generated OH in both adsorbed and radical states promotes C–C coupling via CO-H 2 CO bonding and facilitates hydrogenation through proton transfer. Additionally, the presence of adsorbed H 2 O and OH enhances the desorption of ethanol, further enhancing alcohol selectivity. It is envisaged that these findings would inspire value-added transformation of CO 2 to produce higher alcohols and pave the way for efficient chemical processes.