Heteroatom-doped Biochar for Direct Dehydrogenation of Propane to Propylene

Carbon materials have been widely used in various catalytic reactions due to their excellent properties, such as low cost and good chemical/ thermal stability. In this study, nitrogen-doped, boron-doped, and boron-nitrogen co-doped biochars were prepared by in-situ gas-phase doping strategy using natural absorbent cotton as the raw materials. In the reaction of direct dehydrogenation of propane to propylene, the heteroatom-doped biochar showed higher propane conversion and propylene selectivity than the undoped biochar. It was also found that the catalytic performance of nitrogen and boron independently doped biochar was better than that of boron and nitrogen co-doped biochar. The nitrogen-doped biochar exhibited the best catalytic performance of which, at the reaction temperature of 600 degrees C, the propane conversion reached 17.6%, and the olefins yield was 14.8%. After dehydrogenation reaction for 12 h, the catalyst's performance exhibited no apparent declination. The characterization results revealed that nitrogen doping and boron doping in biochars could transform many C-O groups on the surface of biochar into C=O groups at an advantage of propane dehydrogenation activity, which inhibits the C-C bond breaking in the reaction process and improves the selectivity of propylene. Furthermore, duo to biochars rich in resources and low cost, they would promote the industrialization of direct dehydrogenation of propane.