Silver modified Cu/SiO2 catalyst for the hydrogenation of methyl acetate to ethanol

A series of silver modified Cu/SiO2 catalysts were synthesized with ammonia-evaporation method and applied in vapor-phase hydrogenation of methyl acetate to ethanol. The influence of additive ‘Ag’ on the structural evolution of catalyst was systematically studied by several characterization techniques, such as N2 adsorption–desorption, N2O titration, PXRD, FTIR, in-situFTIR, H2-TPR, H2-TPD, XPS and TEM. Results showed that incorporation of a small amount of Ag could enhance the structural stability, and the strong interaction between Cu and Ag species was conducive to increase the dispersion of copper species and create a suitable Cu+/(Cu0 + Cu+) ratio, which was proposed to be responsible for the improved catalytic activity. The maximum conversion of MA (94.1%) and selectivity of ethanol (91.3%) over optimized Cu-0.5Ag/SiO2 and 120 h on stream without deactivation under optimal conditions demonstrates its excellent stability.