Preparation Of Carbon Fiber-Based Material And Its Catalytic Combustion Performance Of Toluene

The emission of volatile organic compounds (VOCs) has dramatically increased, of whith aromatic compounds are the most harmful pollutants among hazardous VOCs. Catalytic combustion is the most effective method for the destruction of VOCs, developing the efficient catalysts has become urgent issue. Mn-Ce composite catalysts have attracted wide interest for their high activity in catalytic combustion, meanwhile activated carbon fibers (ACF) have also been regarded as a promising support for its large specific surface area. In this work, a series of ACF supported MnCeOx composite catalysts (Mn-Ce/ACF) catalysts were prepared by impregnated method and its catalytic combustion performance of toluene was investigated. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and others were applied to explore the structure, morphology and composition of the catalysts, the influence of the catalyst fabrication parameters and operating parameters on toluene combustion were studied.Results showed that the oxygen functional groups in ACF and the structure of MnCeOx particle and interaction in MnCeOx have played important roles in the combustion process. ACF modified by HNO3 have increased the number of oxygen functional groups, which can enhance the adsorption capacity and promote the dispersion of MnCeOx like a target, MnCeOx particle in good crystalline structure appeared on original ACF and ACF modified by NaOH. In the result, the 10% Mn-Ce/ACF that calcined at 450 ? and prepared in excessive solution gave the best catalytic activity, which could be attributed to the formation of Ce-O-Mn solid solution. Additionally, the formation of Ce-O-Mn solid solution was investigated by different impregnation sequence, high catalytic activity was obtained by one-step way, where Mn ion could be gradually incorporated into the cubic lattice CeO2 to form a homogeneous solid solution, and Ce-O-Mn solid solution have more structure defects.The catalyst exhibited 10 h steady catalytic activity, over which the toluene conversion was up to 85%at 230 ?. The adsorbed oxygen species came from O2 in air, and transformed into lattice oxygen gradually. The used catalysts had littile change in crystalline structure, and the content of Mn4+decreased, Ce4+ shifted into Ce3+, mechanism of toluene decomposition that contained three pathways was complicated and deduced, of which the main route was methyl oxidization and opening of aromatic-ring.