Highly effective microwave catalytic oxidative dehydrogenation of propane by CO2 over V-La-doped dendritic mesoporous silica-based microwave catalysts

• A new and effective method for CO 2 -ODHP by microwave catalysis has been developed. • Doping of La in V-MSNS significantly enhanced the catalytic activity. • Ea’ for V-La-MSNS + SiC drops from 132.7 kJ/mol in the CRM to 71.4 kJ/mol in the MCRM. • Deactivated catalyst can be restored by in-situ regeneration in the MCRM.. • Catalytic activity in the MCRM is much higher than that in the CRM. The great potential of the oxidative dehydrogenation of propane by CO 2 (CO 2 -ODHP) reaction in facilitating propylene production from propane and elimination of CO 2 has attracted much attention. However, the challenge of the oxidative dehydrogenation of propane by CO 2 (CO 2 -ODHP) reaction is the high thermodynamic stability of CO 2 , which requires high temperature for activation but the predominance of propane cracking reactions at high temperatures leads to difficulties in maintaining high selectivity for propylene at high conversion rates. Herein, a new and effective method for CO 2 -ODHP by microwave catalysis has been developed. Meanwhile, a novel vanadium-lanthanum-doped three-dimensional dendritic mesoporous silica nanospheres (V-La-MSNS) based microwave catalyst is synthesized by the in situ growth approach. Importantly, the propane conversion increases from 2% in conventional reaction mode (CRM) to 13% in microwave catalytic reaction mode (MCRM) at 500 °C, with the propylene selectivity still remained at a high level. The catalyst exhibits good stability and reproducibility in microwave catalytic reaction mode. Besides, the doping of La in V-MSNS can dramatically increase the catalytic activity. More importantly, the apparent activation energy of the V-La-MSNS + SiC microwave catalyst drops from 132.7 kJ/mol in the CRM to 71.4 kJ/mol in the MCRM, indicating a significant microwave direct catalytic effect. This work presents a new method for high-efficient catalytic CO 2 -ODHP reaction under microwave irradiation.