금속 산화물 촉매에 의한 벤젠의 산화 반응에 관한 연구

Abstract

Catalytic combustion of benzene over various catalyst has been investigated. The catalysts have been prepared by malic acid method, microwave irradiation method, microwave explosion method, urea method, solid method, co-precipitation method, impregnation method, wet-impregnation method, precipitation method and ball mill method. These catalysts were characterized by XRD, BET, TG/DTA, TEM, ESR, FT-IR, TPR and XPS in order to determine the properties of various catalysts. In addition, their catalytic activities on benzene combustion reaction in the presence of oxygen were also examined the following conclusions are drawn.

Perovskite-type oxides were successfully prepared by malic acid method and microwave irradiation method. The LaMnO3 catalysts, by malic acid method, showed the highest activity and the conversion reaches almost 100% at 350 ℃. The catalysts were modified to enhance the activity through substitution of metal into the A or B site of the perovskite oxides. In the LaMnO3-type catalyst, the partial substitution of Sr into the A-site enhanced the catalytic activity in the benzene combustion. In addition, the partial substitution of Co or Cu into the B-site also enhanced the catalytic activity and the catalytic activity was in the order of Co > Cu > Fe in the LaMn1-XBXO3 (B = Co, Fe, Cu) type catalyst. LaMnO3 catalysts prepared by microwave irradiation method, shown increased catalytic activity compared to malic acid method. LaMnO3 catalyst, by microwave irradiation method, showed the highest activity and the conversion reaches almost 100% at 275℃.

CuO-CeO2 catalysts were prepared by malic acid method, urea method, solid method, co-precipitation method, microwave irradiation method, microwave explosion method. Microwave explosion method lead to the highest activity of catalyst among various other synthesis methods. CuO-CeO2 catalyst, Cu:Ce=3:7, was high activity than other Cu:Ce mixture ratio. CuO-CeO2 catalyst, by microwave explosion method, showed the highest activity and the conversion reaches almost 100% at 300℃.

Catalytic combustion of benzene over CeO2-supported copper oxides has been investigated. The supported copper oxide catalysts were prepared by use of lots of loading method, such as impregnation method, wet-impregnation method, ball mill method, and precipitation–deposition method. In precipitation method, solution pH was changed. CuO/CeO2 catalysts prepared by use of precipitation method contained highly dispersed copper oxide species at high loading ratio. The CuO supported on CeO2 prepared at pH 7 had the highest activity, with conversion reaching almost 100% at 210℃. However, CuO supported on CeO2 prepared without NaOH had poor activity. In addition, catalytic activity increased with increasing CuO loading ratio, with the 10 wt% loaded CuO/CeO2 catalyst having the highest activity.