Effect of Cu-doping on the structure and performance of molybdenum carbide catalyst for low-temperature hydrogenation of dimethyl oxalate to ethanol

Several copper-doped molybdenum carbide (Cu-Mo2C) nanomaterials for the hydrogenation of dimethyl oxalate (DMO) to ethanol at low temperature (e.g., 473 K) have been developed through a facile solid-state pyrolysis method. Characterization techniques including X-ray diffraction, scanning/transmission electron microscopy, N-2-physisorption, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy were employed to reveal the morphology, structure and properties of the synthesized nanomaterials. The characterization and reaction results suggest that the incorporation of copper species in Mo2C plays a crucial role in modifying the morphologic structure of Cu-Mo2C as well as tuning the electronic state of Mo active sites, resulting in an important enhancement in the catalytic performance. Moreover, a strong synergistic effect between Cu and Mo2C is observed in DMO hydrogenation. Accordingly, the 67.2% yield of ethanol can be attained at a low temperature of 473 I< over the Cu-Mo2C nanomaterials with a suitable atom ratio (e.g., Cu:Mo = 0.03:1), which are higher than those obtained by using a pure Mo2C (e.g., 13.7%) under the same reaction conditions. The Cu-doped Mo2C nanomaterials also display excellent catalytic stability during the hydrogenation of DMO to ethanol for longer than 300 h. (C) 2016 Elsevier B.V. All rights reserved.