Preparation, Characterization and Catalytic Activity of Niobium Oxynitride and Oxycarbide in Hydrotreatment

Abstract

ABSTRACTOxynitride and oxycarbide of niobium present metallic and acidic catalytic functions as evidenced by molecular probe reactions: isomerization of cyclohexane and hydrodenitrogenation of 1–4 tetrahydroquinoline. The proximity of the two functions leads to the concept of “dual site” by selective inhibition of the metallic and acid sites. Substitution of nitrogen of the oxynitride by carbon to form the oxycarbide produces a large enhancement of the metallic character of the surface. The oxynitride was shown to present a more acidic and a less hydrogenating activity as compared to the activity of the oxycarbide. Both compounds of niobium have been compared to molybdenum oxynitride.