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

A new synthesis for the preparation of the bimetallic carbide, Co 3 Mo 3 C, as well as syntheses for the preparation of alumina-supported Ni 2 Mo 3 N, Co 3 Mo 3 N, and Co 3 Mo 3 C 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 Co 3 Mo 3 C is prepared in a two-step synthesis in which oxide precursors are converted to Co 3 Mo 3 N, which is subsequently carburized to give the bimetallic carbide. Alumina-supported Ni 2 Mo 3 N and Co 3 Mo 3 N are prepared from supported oxide precursors via nitridation in flowing NH 3, while the carburization of bulk and alumina-supported Co 3 Mo 3 N utilizes a CH 4 /H 2 mixture to yield the bimetallic carbide products. Elemental analysis of a 22.5 wt % Co 3 Mo 3 C/Al 2 O 3 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 O 2 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.