Designing and understanding efficient catalysts for CO2 hydrogenation to ethanol on trinuclear Cu-ZSM-5 frameworks

CO 2 hydrogenation to ethanol is an attractive strategy to mitigate greenhouse gas emissions while producing easily useful fuels. In this study, we perform a comprehensive ab initio multiscale study combining density functional theory and a microkinetic batch reactor modelling to elucidate the mechanism of ethanol formation via CO 2 hydrogenation over a trinuclear Cu-ZSM-5 catalyst. Two different zeolite framework configurations (-Al-Si-Al- and -Al-Si-Si-Al-) are systematically investigated to identify bi-substituted sites. Then, a stable trinuclear Cu-ZSM-5 model is found by structural optimization and copper coordination analysis. Subsequent investigation of the adsorption modes of reactive species reveals the complete reaction pathway, with the explicit determination of all listed elementary steps and associated energy barriers. By implementing these findings into a coupled microkinetic framework, we establish 250 °C as the optimal temperature for ethanol production. Additionally, a stoichiometric H 2 /CO 2 ratio of 3:1 is identified as the most effective condition to enhance ethanol synthesis. The derived results exhibit strong agreement with previous theoretical studies on analogous systems and show remarkable agreement with experimental observations, conclusively confirming the superior catalytic activity of trinuclear Cu-ZSM-5 in this reaction system. • Triple copper active sites are identified and incorporated into the ZSM-5 zeolite framework. • A Cu-ZSM-5 structure model is developed to facilitate ethanol production via CO 2 hydrogenation. • Microkinetic modelling is coupled with DFT calculations to simulate realistic reaction conditions. • Theoretical simulations provide crucial insight into C C coupling to inform and guide experiment investigations.