PORE STRUCTURE OF BULK TUNGSTEN CARBIDE POWDER CATALYSTS

Bulk tungsten carbide catalysts are prepared by direct carburization/r eduction of tungsten trioxide in methane-hydrogen mixtures. The cataly tic properties of such catalysts have been studied by several authors. The porous structure of these catalysts is studied by adsorption of N -2, Kr, CF4 and neohexane. Adsorption isotherms and hysteresis loops f or the catalysts suggest the presence of a microporous structure made of parallel plates distant approximately by 20 Angstrom. These results are compared to those obtained using such catalysts for hydrogen oxid ation and where condensation in the porous structure was observed.