Carbon nanofibers modified with boron, phosphorous and nitrogen as metal-free catalyst for propane oxidative dehydrogenation

摘要

Carbon nanofibers (CNFs) were modified with B and P by an ex-situ approach. In addition, CNFs doped with nitrogen were prepared in-situ using ethylenediamine as N and C source. After calcination, the doped CNFs were used as catalyst for the oxidative dehydrogenation of propane. For B-doped CNFs, the effects of boron loading and calcination temperature on boron speciation and catalytic conversion were studied. For the same reaction temperatures and conversions, B and P doped CNFs exhibited higher selectivities to propene than pristine CNFs. The N-doped CNFs were the most active but the least selective. Our results also show that the type of phosphorous precursor affects the selectivity to propene and that CNFs modified using triphenylphosphine as precursor exhibited the highest selectivity at isoconversion.