Hydrogenation of cinnamaldehyde over bimetallic Au-Cu/CeO2 catalyst under a mild condition

Bimetallic Au_xCu_y/CeO₂ (x/y=3/1, 1/1, and 1/3) catalysts were prepared by direct anion exchange (DAE), following impregnation (IMP) methods, and used for selective hydrogenation of cinnamaldehyde. The effects of pretreatments, such as calcination or reduction on the catalytic activities of these catalysts were investigated. XRD and HRTEM showed that for the reduced catalysts, there is the formation of an Au-Cu alloy. HAADF-STEM displayed that reduction pretreatment leads to a very homogenous distribution of Au and Cu on the external catalyst surface. Reaction parameters, such as CAL concentration, the stirring speed, nature of the solvent influence the catalytic activities. Pretreatments lead to a major effect on CAL conversion and HCAL selectivity. Catalysts Au_xCu_y/CeO₂pretreated under reduction display higher CAL conversion and HCAL selectivity than that of under calcination mainly due to the synergistic effect resulting in a formation of Au-Cu alloy.