Synthesis, characterization and hydrotreating activity of nanostructured systems on carbon supported vanadium

Abstract

A novel synthesis route was designed to obtain highly active vanadium based catalysts. Three different activated carbons were used as supports (one of them being treated with ozone). The supported catalysts were characterized by XRD, TEM, XPS and EPR. These systems were tested in hydrotreating reactions (HDS, HDN and hydrogenation). The characterization results showed well dispersed vanadium nanoparticles. However, it was evidenced that during the synthesis process, a vanadium carbide phase was produced within vanadium oxides. Reactivity studies showed that the vanadium catalysts were slightly better for HDS and hydrogenation reactions than a commercial NiMoS catalyst, but that was not the case for HDN reactions. The reduction method proposed is potentially an excellent route to synthesize more active supported vanadium carbide catalysts than the conventional TPS method. Under reaction conditions, carbide and sulfide vanadium species coexist in the catalyst; vanadium carbide sites probably remain intimately mixed with the active vanadium sulfide sites.