Highly-Dispersed Copper-Based Catalysts from Cu–Zn–Al Layered Double Hydroxide Precursor for Gas-Phase Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

The highly-dispersed copper-based catalysts for the gas-phase hydrogenation of dimethyl oxalate to ethylene glycol (EG) were prepared from a Cu–Zn–Al layered double hydroxide (LDH) precursor. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, H2 temperature programmed reduction (H2-TPR) and H2–N2O titration indicated that the composition, texture, and structure of resulting copper-based catalysts were profoundly affected by the calcination temperature of LDH precursor. Moreover, the as-synthesized catalyst calcined at 600 °C was found to exhibit a superior catalytic hydrogenation performance with an EG yield of 94.7 % to the other catalysts calcined at 500 and 700 °C, which should be mainly attributed to the presence of the highly-dispersed active metallic copper species over metal oxide matrix.