N-, P- and B-doped mesoporous carbons for direct dehydrogenation of propane

Abstract

Mesoporous carbons doped with nitrogen, phosphorous and boron are prepared by a post-treating method or in situ approach. All the samples present a well-defined mesoporous structure and the dopants distribute uniformly with special chemical structures. In a direct propane dehydrogenation reaction, phosphorous- and boron-doped mesoporous carbons (PMC, BMC) exhibit improved propane conversion and propene selectivity, in comparison with undoped mesoporous carbon (MC). Nitrogen-doped mesoporous carbons (NMC) show decreased activity, although having higher surface area and larger pore volume than MC, PMC and BMC. Through comparative analysis of the chemical structures and oxygen-containing groups in these carbon materials, it is found that the amounts of carbonyl and/or quinone groups of the carbons play a pivotal role in direct dehydrogenation of propane. Doping with heteroatoms affects the compositions and contents of the oxygen-containing groups, and then ultimately the catalytic ability of the carbon catalysts.