Oxidative Dehydrogenation Of Propane Over Nanodiamond Modified By Molybdenum And Phosphorous Oxides

The demand for alkenes is one of the most pressing issues in petrochemical industry. The oxidative dehydrogenation (ODH) of alkanes provides a promising alternative route for the production of alkenes that avoids drawbacks of the catalytic direct dehydrogenation (DH). As the main components, vanadium and molybdenum oxides have been widely used as the ODH catalysts. Despite a great deal of research, alkene selectivity in the current ODH process is still limited owing to the severely combustion of hydrocarbons. In recent years, nanocarbons provide a great potential as catalysts or catalyst supports in the ODH of alkanes. Threrfore it would be very interesting to further study the modification effect of metal oxides on nanocarbons in ODH reaction.MoOx and POx-modified nanodiamond (ND) catalysts were investigated for oxidative dehydrogenation (ODH) of propane. The catalysts were prepared by impregnation method and characterized by SEM, TEM, XPS, XRD, Raman and IR techniques.The reaction results demonstrate that ND shows superior catalytic performance than CNTs in ODH of propane. A small amount of POx can improve the propene selectivity, but excess POx results in a severe decrease in overall activity. On the other hand, in general, adding MoOx increases the activity but decreases the propene selectivity. As a special case,1MoON-modified ND catalyst exhibits higher propane conversion and propene selectivity than ND, and higher propene yield than1MoOx1POx catalyst. Compared with oCNTs, ND is more effective modified by MoOx and POX.The characterazation results demonstrate that The surface species on the ND include two-dimensional polymerized MoOx and POx, and further aggregate as the loading increases. The degree of graphitization of ND increases after the reation, which is believed to be favourable to the reation.