VOCs and carbonaceous particles removal assisted by NOx on alkali0.15/ZrO2 and Csx-M0.1/ZrO2 catalysts (M = Cu or Co)

The effect of alkali metals on the physicochemical characteristics of zirconium oxide and the properties of alkali metals in the oxidation of toluene and/or carbonaceous particles and/or conversion of nitrogen oxides have been studied. We observed that they had an effect on the structural and textural properties of ZrO2. These solids were tested first in the oxidation of toluene and carbonaceous particles separately and secondly with both pollutants. Whatever the experiments, the sample Cs0.15/ZrO2 was found to be the catalyst the most active. The simultaneous removal of toluene and soot shows that the presence of toluene leads to a decrease in the temperature of the maximum soot oxidation rate, particularly with catalysts impregnated of Cs and Cu. The effect of the Cs/Co ratio on NOx conversion and toluene oxidation was also studied. It was found that the oxidizing properties of NOx can increase the conversion of toluene. This phenomenon occurs especially in the presence of catalysts with a low amount of alkali metal. For the oxidation of carbonaceous particles on the samples Cs/ZrO2 impregnated with transition metals, the best performance is obtained for copper, although a decrease of the ratio Cs/Cu leads to a slower oxidation and a shift to higher temperatures. (authors)