Synthesis of Bulk and Alumina-Supported Bimetallic Carbide and Nitride Catalysts

A new synthesis for the preparation of the bimetallic carbide, Co3Mo3C, as well as syntheses for the preparation of alumina-supported Ni2Mo3N, Co3Mo3N, and Co3Mo3C are described. The syntheses utilize the temperature-programmed reduction (TPR) method in which solid-state precursors are converted to the desired products in the presence of gas-phase reactants. Bulk and alumina-supported Co3Mo3C is prepared in a two-step synthesis in which oxide precursors are converted to Co3Mo3N, which is subsequently carburized to give the bimetallic carbide. Alumina-supported Ni2Mo3N and Co3Mo3N are prepared from supported oxide precursors via nitridation in flowing NH3, while the carburization of bulk and alumina-supported Co3Mo3N utilizes a CH4/H2 mixture to yield the bimetallic carbide products. Elemental analysis of a 22.5 wt % Co3Mo3C/Al2O3 catalyst suggests incomplete replacement of N with C under the synthesis conditions employed. The alumina-supported carbide and nitride materials have high surface areas and O2 chemisorption capacities, suggesting that these syntheses provide an excellent route for the preparation of heterogeneous catalysts in which bimetallic carbides and nitrides are the active component.