Catalysis Today, Vol.339, 352-361, 2020
Hydrogenation of CO2 to methanol over Cu/AlCeO catalyst
The hydrogenation of CO2 to methanol is one of the most promising ways to reduce the CO2 emission and mitigate the energy shortage, but it still confronts low CO2 conversion and methanol selectivity. In this work, the Cu/Al2O3, Cu/AlCeO and Cu/CeO2 catalysts with 60 wt% Cu were prepared by co-precipitation method for the CO2 hydrogenation to methanol, and the Cu particles were well dispersed on the supports. It was found that the composite of Al2O3 and CeO2 can inhibit the growth of Cu crystallite, and the Cu/AlCeO had the smaller Cu particles, which was beneficial for catalytic activity improvement. Besides, CeO2 introduced in the catalysts increased the surface basicity and the atom ratio of Cu+ species, which promoted the methanol selectivity. Kinetic experiments indicated that the Cu/AlCeO catalyst had the lowest apparent activation barriers for CO2 activation and methanol synthesis. In the process of reaction, CeO2 in the catalysts can inhibit the agglomerate of Cu, which improved the stability of catalysts. Hence, the Cu/AlCeO catalyst showed the highest space time yield (STYmethanol) for CO2 hydrogenation into methanol. And the STYmethanol was 11.9 mmol h(-1) g(-1) at 533 K, V (H-2)/V(CO2) = 3/1, gas hourly space velocity (GHSV) = 14,400 mL h(-1) g(-1) and P = 3 MPa.