Polyfunctionality of DeNOx catalysts in other pollutant abatement

The total oxidation of o-dichlorobenzene over differently loaded V2O5/TiO2-based catalytic materials was studied. A series of vanadium-supported catalysts have been prepared, by incipient wetness impregnation, on different commercial supports (bare TiO2, TiO2/WO3 and TiO2/WO3/SiO2). The prepared materials were characterized by XRD, H2-TPR, Raman spectroscopy and surface area measurements. All the catalysts exhibited high oxidation activity and the content of vanadium in the system was demonstrated to be important in controlling the catalyst activity and selectivity. Isolated and well dispersed vanadium sites resulted beneficial for o-DCB conversion. Thus, in spite of the lower ability of SiO2 to spread metal oxides the higher resistance to sintering of silica-containing materials also at high vanadium content, favors VOx dispersion and leads to superior catalytic performance. Nevertheless, the presence of tungsten on the support and of high amount of vanadium also lead to the formation of partial oxidation products. In particular, di-chloromaleic anhydride was formed and its production seems to be connected to the distribution of acidic sites.