Highly active and stable CeO2–SiO2 supported Cu catalysts for the hydrogenation of methyl acetate to ethanol

• The CeO2-modified Cu–SiO2 catalysts achieved good activity and stability.
• Adding a suitable amount of cerium improved the copper dispersion and enriched the surface Cu+ species.
• Adding a suitable amount of cerium restrained the aggregation and valence change.

A series of Cu–CeO2–SiO2 catalysts for the hydrogenation of methyl acetate to ethanol with different CeO2 contents was prepared by an ammonia-evaporation method. Compared with the Cu–SiO2 catalyst, the catalytic activity and stability of the Cu–CeO2–SiO2 catalyst were greatly enhanced with an optimized CeO2 content of about 30 wt.%. The structures of the catalysts were characterized by N2 physisorption, N2O chemisorption, X-ray diffraction, H2 temperature-programmed reduction, NH3-temperature programmed desorption and X-ray photoelectron spectroscopy. The results showed that adding an appropriate amount of cerium to Cu–SiO2 catalysts strengthened the interaction between the cupreous species and the support, diminished the copper crystallite size, improved the copper dispersion and enriched the surface Cu+ species. In addition, several characterizations were performed to investigate the structure changes of the catalysts after stability test, which demonstrated that the CeO2-modified Cu–SiO2 catalyst restrained the aggregation and valence change of cupreous species under reaction conditions.