Study On Catalytic Oxidation Of Benzene By Ru/TiO 2 Doping Promoter

Catalytic oxidation is one of the most effective strategies to remove benzene. Firstly, MOx/TiO2(M=Mn, Ce, Co, Fe) were prepared using the impregnation method and evaluated in benzene oxidation. MnOx/TiO2 showed better catalytic performance than other samples, and the reaction mechanism of benzene oxidation over MnOx/TiO2 was proposed. Secondly, Ru-based catalysts modified by cocatalyst of Mn were studied, and Mn doping did not improve the catalytic activity of Ru-based catalyst. Subsequently, differnet cocatalysts M(M=Co, Ce, Cu, Fe) were tested, and Co was proved to be the best cocatalyst. The preparation methods were studied. Noteworthy, the reaction mechanism of benzene oxidation over Ru-based catalysts was also proposed.In this artcle, the following results were obtained.(1) MOx/TiO2(M=Mn, Ce, Co, Fe) were evaluated in benzene oxidation and MnOx/TiO2 showed best catalytic performance. With the increase of Mn amount, the catalytic activity of MnOx/TiO2 gradually increased. The reaction intermediates such as phenolate, benzoquinone, acetate, maleate species were detected on the surface of MnOx/TiO2. Accordingly, the reaction mechanism of benzene oxidation over MnOx/TiO2 was proposed.(2) Ru-M/TiO2(M=Mn, Co, Ce, Cu, Fe) were evaluated in benzene oxidation and Ru-5Co/TiO2 showed the best catalytic performance. Thus, Co was employed as the typical cocatalyst. Different catalysts were prepared using three methods and evaluated in benzene oxidation, and the best method was confirmed. Ru-5Co/TiO2 showed better catalytic activity than Ru-(y)Co/Ti O2(y=1, 3, 10) for oxidation benzene. Hence, the content of Co3O4 was determined to be 5wt.% in the following research.(3)The main path for benzene oxidation over Ru-5Co/TiO2 is described as follows: 1) Benzene was absorbed on the active site. 2) Benzene was oxidized into phenolate. 3) Ketone was formed through phenolate. 4) Aromatic compounds were decomposed to aldehyde, acetate and maleate species. 5) Non-aromatic compounds were oxidized into final products of CO, CO2 and H2 O.The research in this paper provide the theoretical and experimental supports for benzene oxidation over Ru-based catalysts. Besides, it is meaningful for the research of transition metal cocatalyst modified noble metals catalysts.