Synthesis Of Fe-Ce Oxide Catalysts Using Hard Template Method And Its Catalytic Performance For Toluene Oxidaiton

Volatile organic compounds are very important air pollutants and the removal of VOCs has become a hot topic in the recent years. The catalytic oxidation method can remove low concentration VOCs, by which CO2and H2O are produced directly without any by-products. It’s of great significance for developing cheap, low-temperature and easily industrialized catalysts. The cheap Fe-Ce oxide catalyst was synthesized by hard template method and its catalytic capability for toluene was studied. The main contents of this paper are as follows:(1) Five types of mesoporous silica with different sizes of mesopores were obtained By changing the dosage of TMB. Through BET, XRD and SEM it was found that the pore size, pore structure and the degree of order differed from each other. The pore sizes turned larger after adding TMB. When the dosage increased, the pore sizes became larger. In addition, the specific surface area became lower and the micropore volume became less at the same time; small angle XRD patterns showed that after the addition of TMB, the degree of order changed. When a small amount of TMB was added, a low degree of order was formed. The ordered structure was damaged with the addition increased gradually. SEM results showed the morphology of the samples changed from spindle pattern to ball pattern, at last it turned to amorphous pattern. The sample with best ordered structure was chosen for the next experiment.(2) Fe-Ce composite oxides were synthesized using the sample which was chosen before as the hard template and at the same time typical coprecipitation method was used to synthesize the composite oxides. Then catalytic performance for toluene oxidaiton was studied. Fe2O3showed a better performance than CeO2and the catalyst showed the best catalytic performance for toluene oxidation when the molar ratio of Fe and Ce was1:1. The catalyst prepared with hard template method exhibited the better performance compared with catalysts prepared by other methods and the toluene conversion was close to90%at350℃. The crystalline fluorite structure for CeO2with the characteristic peaks was observed. However, no characteristic peaks for Fe2O3was observed.It was probably the formation of a kind of solid solution or the high dispersion Fe2O3on the surface of CeO2.