Atomic layer deposition of Ga2O3 on γ-Al2O3 catalysts with higher interactions and improved activity and propylene selectivity in CO2-assisted oxidative dehydrogenation of propane

We synthesized Ga2O3 on gamma-Al2O3 support with atomic layer deposition method (ALD) for the CO2-oxidative dehydrogenation of propane (CO2-ODHP). The Ga loading from 1 to 2.9 wt% was controlled by the number of ALD cycles from 1 to 3. For the comparison purposes, the equivalent catalysts were prepared with incipient wetness impregnation method. The catalysts were characterized by a variety of methods including temperature programmed desoprtion of NH3 (NH3-TPD), X-ray photoelectron spectroscopy (XPS) and high resolution trans-mission electron microscopy (HRTEM) and energy dispersive spectroscopy mapping (EDS-Mapping). We iden-tified the ALD catalysts more active and selective in CO2-ODHP reaction due to the higher surface total moderate acidity, Ga-O-Al linkages and Ga2O3 dispersion. The ALD-3C, with 2.9% Ga as the catalyst with the highest performance, gave 38% conversion and 82% selectivity to propylene after 120 min of CO2-ODHP reaction at 600 degrees C which was equal to 96% improvement in the propylene yield.