Molybdenum carbide catalyst formation from precursors deposited on active carbons: XRD studies

Molybdenum carbide is a promising catalyst in many reactions. Its formation was investigated by XRD for two different active carbons: commercial one (NC100) and made out of expanded graphite. They were impregnated by MoCl5 from vapor phase and carbonized in a stream of hydrogen. XRD studies were performed both in ex situ and in situ conditions. Formation of different crystallographic carbide phases (stable, hexagonal Mo2C and/or unstable cubic molybdenum carbide) was observed depending on the conditions of carbidization. The reported earlier catalytic behavior at low temperatures were rationalized in terms of formation of these phases and oxy- or oxyhydrocarbides.