Catalytic Deep Oxidation of Volatile Organic Compounds Toluene and Toluene+Xylene over γPt/γ-Al 2 O 3 Catalysts at Lower Temperatures

The catalytic activity of catalysts for the oxidation of toluene and toluene+xylene mixture was investigated in the microreactor of fixed-bed type. The calcination temperatures and loadings of catalysts played the important role in the activity of catalysts for the oxidation of toluene. The increasing calcination temperatures and loadings of catalysts increased the crystallite size of the platinum to result in the higher oxidation activity of catalysts. The catalytic activity for the toluene oxidation over catalysts turned out to be increasing in the order of $500^{\circ}C\; catalysts calcined at for 3 hrs in the air showed the highest activity for the oxidation of the toluene. The decrease of oxidation activity of catalysts calcined at might result from the decrease of active sites by sintering of platinum metals as well as supports. The 1.0wt% catalyst showed the activity from the lower temperature at , reached the light-off temperature () at , and leveled off its activity at with the conversion of 100% 'Mutual promotion' effects were observed for the binary mixture of toluene and xylene. The activity of the easy-to-oxidize toluene was slightly increased with the existence of the xylene. It might suggest the different mechanism for the oxidation of toluene and xylene on the catalysts on different sites, and its reaction of gaseous oxygen.