Ni-Mo nitride catalysts: Synthesis and application in the ammoxidation of propane

Five different methods were used to prepare the Ni-Mo oxide precursors including sol-gel, rotary evaporation-microwave drying, co-precipitation, impregnation, and mechanical mixing. Ni-Mo nitride catalysts have been synthesized by temperature-programmed nitration of the oxide precursors in a flow of H2 and N2. The structure and physico-chemical properties of the Ni-Mo oxide precursors and their corresponding nitride catalysts were determined by X-ray diffraction, total nitrogen content analysis, X-ray photoelectron spectroscopy and H2 temperature-programmed reduction, and their catalytic performance for propane ammoxidation was also tested. The catalytic activity and selectivity towards the formation of acrylonitrile over the Ni-Mo nitride catalysts are strongly dependent on the preparation methods for the oxide precursors. The N species in the Ni-Mo nitrides and their mobility and reactivity affect the selectivity for acrylonitrile. The Ni-Mo nitride prepared by co-precipitation, with the largest amount and more reactive N species, exhibited the highest catalytic activity and selectivity for acrylonitrile.