Role of Constituent Oxides for Thermal Mineralization of o‐Dichloro Benzene over Mixed‐Oxide‐TiO2 Catalysts: A Mechanistic Explanation

Catalysts with V2O5, WO3 and V2O5−WO3 dispersed over TiO2 were synthesized using sol‐gel technique and thoroughly characterized by various techniques. The catalysts were evaluated for degradation of ortho‐dichloro benzene (o‐DCB) in air/helium, a representative probe molecule for polychlorinated dibenzo‐para‐dioxin and polychlorinated dibenzofuran by employing in situ Fourier‐transform infrared spectroscopy (FT‐IR spectroscopy). Different intermediate species formed on the surface of the TiO2 supported catalysts through of interaction of sorbate molecules with the lattice and/or gaseous oxygen were investigated in detail. Analysis of vibrational bands, observed during sorption of o‐DCB and o‐DCB‐air mixture as a function of temperature over these catalysts, delineated the role of surface intermediate species such as phenolate, enolates, maleates, carboxylates, carbonates in mineralization of o‐DCB. Nature and stability of intermediate species, found to be different over these catalysts, were able to elucidate the catalytic activity trend. Mechanistic insight for thermal mineralization of ortho Dichloro Benzene (o‐DCB) (a representative for Dioxins and Furans) over different mixed oxide catalysts (V2O5 and WO3) dispersed over TiO2 support in presence and absence of oxygen. Creditable evidence obtained for effect of labile lattice of catalysts [V2O5/WO3 and support TiO2] and for disproportionation reaction over biphasic mixed oxide catalyst due to presence of dual oxidation states.