Effect of Calcination Temperature on the Textural Properties and Catalytic Behavior of the Al2O3 Doped Mesoporous Monometallic Cu Catalysts in Dimethyl Oxalate Hydrogenation

Abstract

Al2O3 doped mesoporous monometallic Cu catalysts were successfully synthesized though the self-assembly Cu species derived from the oxalate precursor undergoing thermal decomposing. The evolutions of microstructures, physicochemical and surface properties of the CuAl catalysts have been systematically characterized focusing on the effect of the calcination temperature during catalyst preparation. It is found that the textural and surface properties of the CuAl catalysts were profoundly affected by the calcination temperature, further determining the resultant catalytic behavior in dimethyl oxalate (DMO) hydrogenation. Particularly, the CuAl-500 possessing the maximum surface Cu+ sites and proper surface acid features exhibits 100.0% DMO conversion and 98.0% ethylene glycol (EG) selectivity in presence of the adequate active Cu0 sites, which is superior to that of the other catalysts under the identical reaction conditions. And no activity loss occurred for more than 200 h demonstrated of the outstanding stability of the CuAl-500 catalyst. Moreover, the synergistic effect between surface Cu+ and Cu0 sites should be responsible for DMO selective hydrogenation. Additionally, the strengthened chemical interaction between Cu and Al species endows the catalysts outstanding stability by suppressing the dispersive Cu NPs agglomeration during DMO hydrogenation.