Selective hydrogenolysis of methyl stearate into stearyl alcohol by synergistic catalysis of Cu+ species with the surface oxygen vacancies of ZnAl2O4 spinel

Cu-based catalysts were synthesized utilizing the ZnAl 2 O 4 spinel as supports for the selective hydrogenation of methyl stearate to stearyl alcohol. The presence of Zn atoms inhibited the agglomeration of the particles of Cu species in the reduction process, promoting the distribution of Cu species on the catalyst surface, which will enhance hydrogen activation and selective hydrogenation activity. DFT calculations show that the bond energies of the C-O bonds on both sides of the ester group decrease with the adsorption of the ester molecule onto Cu + species, and the C-O bond energy on the methyl side is lower than that on the carbonyl side. However, because the carbonyl carbon is more susceptible to nucleophilic attack, the C-O bond on the carbonyl side is more easily broken. In addition, the oxygen vacancies of the supports promote hydrogen spillover and the adsorption and activation of ester groups, which further enhance the selective hydrogenation activity of the catalyst on methyl stearate.