Catalyt properties of tungsten oxycarbide and carbide in hydrocarbon conversion

Tungsten oxycarbide with specific surface area ⋍ 24 m²/g was prepared from white tungstic acid by reduction and carburization with CO and H₂. XRD and EXAFS measurements confirmed that the WOC obtained has a simple hexagonal structure isotypic with α-WC and the oxygen is inserted into the trigonal prismatic interstices of the crystal lattice. The reactions of n-hexane, n-heptane and cyclohexane on WOC were studied and compared with WC prepared by direct synthesis at high temperature. WOC and WC are active for the hydrogenolysis, isomerization and dehydrocyclization of alkanes and dehydrogenation of cyclohexane and their catalytic properties are in many ways similar to Pt catalysts. Oxygen insertion inhibits the catalytic activities of tungsten carbide for hydrocarbon conversion reactions probably due to electronic effect.