Preparation Of The Supported Cu-Mn-Ce Catalysts And The Characteristics Of Catalytic Combustion

With the development of industrialization, Volatile Organic Compounds (VOCs) has become one of major sources of atmospheric pollutants. Catalytic combustion is a simple, efficient and environment friendly treatment method to control VOCs pollution. In this dissertation, the catalytic activity, chlorine-resistant and stability of the supported Cu-Mn-Ce were investigated by VOCs combustion, the effect of support on activity of Cu-Mn-Ce composite oxides catalysts were also discussed.A series of precursors of AOX (MgO, Al2O3, SiO2, TiO2and ZrO2) supporters were prepared by co-precipitation, and each precursor was calcined at different temperature. The supported Cu-Mn-Ce catalysts were prepared by impregnation method, and their catalytic performances were investigated by combustions of toluene. The results show that the surface area, surface hydroxyl and the phase structure of these supporters changed significantly with the calcinations temperature. However, for different supporters, the calcinations temperature of precursor has different influence on the performances:With the calcinations temperature from500℃to 1000℃, the catalytic performances of Cu-Mn-Ce/MgO declined obviously, but differently to them, the catalytic performances of Cu-Mn-Ce/Al2O3and Cu-Mn-Ce/SiO2were improved significantly. When the calcinations temperature of the supporter was increased, the catalytic performances of Cu-Mn-Ce/TiO2increased first and then decreased, and the catalytic activity of Cu-Mn-Ce/ZrO2was basically unchanged.In order to researching the support effect indepth, the catalytic performances of Cu-Mn-Ce catalysts were studied by combustions of various types of VOCs, when the calcinations temperature of supporters was500℃. And the catalysts were characterized by TG, XRD, BET and H2-TPR. The results show that a typical support effect is exhibited. The high surface area and the hydroxyl of SiO2and A12O3as well as the the strong interaction between Mn, Cu and MgO were disadvantage for the formation of Cu-Mn-Ce solid solution. However TiO2and ZrO2could maintain the Cu-Mn-Ce solid solution better, thus the catalytic activity was better, especially for oxygenated class of VOCs. And chlorine-resistant and thermal stability of the Cu-Mn-Ce catalyst had been improved greatly.Finally, the TiO2and ZrO2were doped by Si and Ce respectively, and the results show that, the catalytic performances of Cu-Mn-Ce/TixSi1-xO2were decreased comparing with Cu-Mn-Ce/TiO2, while comparing with Cu-Mn-Ce/ZrO2, the catalytic performances of Cu-Mn-Ce/CexZr1-xO2were improved obviously with the increase of Ce. This maybe related to the excellent oxygen storage capacity of CeO2.