| dc.description.abstract | In this study, ZrO2 was incorporated into CeO2 by co-precipitation method to prepare good solid solution Ce1-xZrxO2 mixed oxides. Ce1-xZrxO2 mixed oxides were prepared as supports of CuO/Ce1-xZrxO2 catalysts, which prepared by impregnation method; MnOx was impregnation on Ce1-xZrxO2 as supports of CuO/(MnOx/Ce0.9Zr0.1O2) catalysts; The other to ZrO2 and MnOx was incorporated into CeO2 by co-precipitation method to prepare good solid solution Ce0.9-xZr0.1MnxO2 mixed oxides. Ce0.9-xZr0.1MnxO2 mixed oxides were prepared as supports of CuO/Ce0.9-xZr0.1MnxO2 catalysts, which prepared by impregnation method. Then CuO/Ce0.9-xZr0.1MnxO2 catalysts were used in the complete oxidation reaction of volatile organic compound benzene. Besides the effects of redox properties and the role of MnOx were discussed by three steps study. The benzene vapor feed was diluted with air into the reactor at the flow rate of 100 ml/min (F/W = 6000~24,000 ml h-1gcat-1). The physical and surface properties of catalysts were determined by BET, XRD, Raman, XPS and H2-TPR.
The γ-Al2O3 without redox properties was used as support in CuO/ γ-Al2O3 catalyst which the activity was much lower than CuO/CeO2 over benzene total oxidation reaction. ZrO2 was incorporated into CeO2 can enhance largely redox properties, but CuO/Ce1-xZrxO2 catalyst activeness counter-drop. Redox behavior of support of copper based catalysts was essential for total benzene oxidation but was the critical factor. MnOx was impregnation on Ce0.9Zr0.1O2 can enhance the CuO/(MnOx/Ce0.9Zr0.1O2) catalytic activity obviously, MnOx in the total oxidation of benzene is also playing an important role. The ZrO2 and MnOx was incorporated into CeO2 by co-precipitation method to prepare good solid solution Ce0.9-xZr0.1MnxO2 mixed oxides. When x=0.3, support has the largest surface area and the lattice structure is still perfect. Most of the MnOx into the lattice to enhance the support store/release oxygen storage capacity, a part of the MnOx in the surface modification of dispersed surface Ce0.9Zr0.1O2. The best performance of active is 7%CuO/ Ce0.6Zr0.1Mn0.3O2 (T100=235 °C); most of incorporated manganese over a fraction of 0.3 could not be fixed in the framework of CeO2 and thus appeared as well dispersed Mn2O3.
CuO/Ce0.6Zr0.1Mn0.3O2 catalyst in the total oxidation of benzene, the mixed oxide Ce0.6Zr0.1Mn0.3O2 exhibited considerable reactivity on benzene oxidation, and a slight increase in load after the reactivity of CuO, demonstrated that the CuO is not the active site in the complete oxidation reaction of benzene. Therefore, the key points of Ce0.6Zr0.1Mn0.3O2 supports for complete oxidation reaction of benzene are very important, not only because of itself oxidation, but also because of the synergetic role of offering lattice oxygen to reaction.
CuO/Ce0.6Zr0.1Mn0.3O2 catalysts exhibited good activity and stability toward benzene, and could eliminate a wide range of benzene. Even after 200hr of complete oxidation reaction of benzene, it also showed 100% conversion. It is a very practical and ideal catalyst for complete oxidation reaction of benzene.
| en_US |