Highly active and selective Cu/SiO2 catalysts prepared by the urea hydrolysis method in dimethyl oxalate hydrogenation

Cu/SiO2 catalysts have been successfully prepared via urea hydrolysis method. The catalysts have been systematically characterized by X-ray diffraction, high-resolution transmission electron microscopy, N2-physisorption and H2 temperature-programmed reduction. The results demonstrated the presence of copper nanoparticles and their high dispersion on the SiO2 support. Catalysts with different copper loadings were prepared, and their performances in the hydrogenation of dimethyl oxalate to ethylene glycol were studied. A 100% conversion of dimethyl oxalate and maximum 98% selectivity of ethylene glycol were reached with 15.6 wt.% copper loading at 200 °C and 2 MPa. Furthermore, under the same reaction conditions, the catalyst can maintain the selectivity of 90% when the reduction temperature reduced from 350 °C to 200 °C. The high activity and selectivity over the catalyst may be ascribed to the homogenously distribution of copper nanoparticles on the large surface.

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► Cu/SiO2 catalysts are prepared by urea hydrolysis method.
► The catalysts have highly dispersed Cu particles.
► The catalysts have a small and narrow Cu nanoparticle distribution.
► The catalysts have a relatively low reduction temperature.
► The catalysts show high activity and selectivity in dimethyl oxalate hydrogenation.