Systematic investigation of supported transition metal oxide based formulations for the catalytic oxidative elimination of (chloro)-aromatics - Part II: Influence of the nature and addition protocol of secondary phases to VOx/TiO2

摘要

This contribution reports, for the first time, a systematic investigation of the effect of the adding secondary phases on the activity of VOx/TiO2 based catalysts in the course of the total oxidation of benzene and chlorobenzene as model molecules for dioxins. The catalysts consisted in binary formulations VOx-secondary phases (CrOx, MnOx, SnOx, WOx, NbOx, TaOx, MoOx, ZrOx or BiOx). Three synthesis pathways differing by the order of synthesis of both phases were investigated (1-2, 2-1 and 1,2 both together). Catalysts synthesized in a unique step demonstrated the best activities for the oxidation of benzene. Moreover, WO, and MOO, phases induce a synergetic effect with VOx. XPS demonstrated that this effect resides in the absence of mutual spreading between both phases preventing the VOx covering by the secondary phases and promoting the stabilization of the links VOx-TiO2.