Applied Catalysis A: General, Vol.571, 51-60, 2019
A highly active and selective mesostructured Cu/AlCeO catalyst for CO2 hydrogenation to methanol
Mesostructured catalysts with optimized microstructure and surface properties endowed them attractive catalytic performance. Herein, the mesostructured AlCeO supports with different weight ratio of Al2O3 and CeO2 have been prepared on the basis of a self-assembly sol-gel process, then 15 wt.% Cu was loaded onto the mesostructured AlCeO supports by incipient wetness impregnation method. The mesostructured AlCeO supports with varied ratio of Al2O3 to CeO2 resulted in the very different Cu particle size, and for the optimized catalyst Cu/AlCeO-7 (the amount of Al2O3, in AlCeO support was 70 wt.%), the Cu crystal size was around 7 nm based on the characterization of XRD and TEM. The Cu/AlCeO-7 catalyst had strong metal-support interactions (SMSI) and more Cu-ceria interface, which was confirmed by the XPS. Furthermore, the Cu/AlCeO-7 catalyst showed the highest exposed Cu surface area (S-cu) (25.5 m(2)/g(cat)) from the analysis results of H-2-TPR and dissociative chemisorption of nitrous oxide. The CO2-TPD results demonstrated the Cu/AlCeO-7 had strong surface basicity. Hence, Cu/AlCeO-7 catalyst showed the highest space time yield of methanol (STYMeOH). The CO, conversion (Cu/AlCeO-7, V(H-2)V(CO2) = 3/1, GHSV = 6000 mL h(-1) g(-1) and P = 4 MPa) was up to 22.5% at 553 K, the methanol selectivity can reach 94% at 473 K, and the STYMeOH was up to 7.2 mmol g(cat)(-1) h(-1) at 493 K. The as prepared mesostructured Cu/AlCeO-7 exhibited a promising catalyst candidate for CO2 hydrogenation to methanol.