Molecular-level understanding of hydroxyl group boosted catalytic activity of CuZnAl catalyst in the conversion of syngas to ethanol

Syngas to ethanol is getting attention as one of the promising route to obtain an appealing alternative fuel. A detailed reaction mechanism for ethanol synthesis was constructed on the γ-Al2O3 (110D) surfaces with different hydroxyl coverage using periodic DFT and microkinetic model, which provide the insight into the influence of surface hydroxyl. We found with the increasing of hydroxyl coverage, the interaction between CH3 and CO evolves from attraction to repulsion. The formation of CH3 and CH3CO became more facile on the surface with higher θOH, which is elucidated by the electrostatic potentials and Bader charge analyses. Moreover, the selectivity of CH3CH2OH can be greatly improved by reinforcing the CO adsorption or decreasing the H2/CO ratio. Our study could offer distinctive guidance for the preparation of efficient catalysts and broaden understanding of the mechanism of ethanol synthesis.