Preparation and catalytic activity of active carbon-supported Mo2C nanoparticles

Abstract

Mo₂C nanoparticles dispersed on two kinds of active carbon were prepared and their catalytic properties were tested. One carbonaceous support is a commercial active carbon: NC100, supplied by the French company Pica, while the other is a highly porous monolith derived from compressed expanded graphite. Both materials were impregnated with MoCl₅ in the vapour phase, followed by reduction-carburization at high temperature with a stream of hydrogen. Molybdenum carbide nanoparticles (1–5 nm wide) were thus obtained all over the surface. Such particles were also prepared by impregnation of the monolithic active carbon by (NH₄)₆Mo₇O₂₄·4H₂O in aqueous solution, followed by reduction-carburization in the same conditions. The effect on the catalytic properties of the carbonaceous support on one hand, and that of the precursor of the carbide on the other hand, could thus be investigated. For that purpose, studies of hydrodenitrogenation (HDN) of indole were carried out. The results showed that the monolithic support impregnated in the vapour phase is the best catalyst. Its catalytic activity was finally also studied in hydrodesulfuration (HDS) of dibenzothiophene. For both hydrotreatment reactions, Mo₂C was shown to be a very efficient, with a low hydrogenating activity, hence with a low consumption of hydrogen with respect to more conventional catalysts.