Research On Vanadium- Based Catalystforcatalytic Oxidation Of Chlorobenzene

Vanadia-based catalysts are found widespread application in industrial field. V2O5/Ti O2 is well known commercial catalyst for the selective catalytic reduction(SCR) of NOx with NH3. However, there are still considerable amount of toxic components, such as chlorinated aromatics, furans and dioxins in the flow gas of steel sintering and waste incinerations. Among them, poly-chlorinated dibenzo-p-dioxins and dibenzofurans known as the dioxins, which is a series of chlorinated organic molecules belonging to the category of persistent organic pollutants(POPs).Most of the recent works on the oxidation of chlorobenzene were paid more attentions on Mn-based catalysts or manganese oxides with different morphologies. They proposed that Mn O2 exhibited excellent chlorobenzene conversions at relatively low temperature and even better activities than vanadia-based catalysts, which could be due to the enrichment of surface active oxygen and quantities of Mn4+ cations on the surface. However, manganese oxides showed less resistance to SO2 and cannot stably run for an industrial acceptable period for SCR process along with POPs oxidation.Therefore, one of the alternative methods is to develop new catalysts based on vanadia-based catalysts. Therefore, it is necessary to elucidate the role of Mo O3 for POPs oxidation and compared with WO3 on vanadia-based catalysts. In this paper, V2O5/Ti O2 and V2O5-Mo O3/Ti O2 catalysts were synthesized and its activity was investigated by the oxidation of chlorobenzene. The influences of V2O5 and Mo O3 and the activity comparisons with V2O5/Ti O2 and V2O5-Mo O3/Ti O2 are also studied. Finally, H2-TPR and O2-TPD were carried out to investigate the reducibility and surface oxygen species respectively.The main results of the paper are following:For V2O5-/Ti O2, V5 catalyst has the best catalytic performance.This catalyst achieves 50% chlorobenzene conversion at 205°C, 90% chlorobenzene conversion at 245°CFor V2O5-Mo O3/Ti O2, V1Mo9 catalyst has the best catalytic performance. This catalyst achieves 50% chlorobenzene conversion at 185°C, 90% chlorobenzene conversion at 240°C, 100% chlorobenzene conversion at 300°C. Therefore, the optimum loading of Mo O3 and V2O5 are 9% and 1%.