Co₃O₄-CeO₂ Loaded SBA-15 Monolith Used To Catalyze The Particulate Matters Emitted From Diesel Engines

Diesel engines are widely used because of their high efficiency, low-operating costs, high durability and reliability. However, the emissions from the diesel engines have caused severe environmental problems and threaten the health of human beings. In addition, many countries are formulating laws and regulations to restrict the emission. Hence, the abatement of diesel engine emissions allows of no delay. The traditional way to abate the particulate matters from diesel engines is to apply the diesel particulate filter(DPF). But the active components over DPF are easy to fall off. To solve this problem, we try to prepare a threedimensional(3D) net-linked SBA-15 monolith(SM) using the shearing force assisted sol-gel method to act as a support of soot oxidation catalyst. The main contents are listed as follows:In this paper, we firstly synthesized the 3D net-linked SBA-15 monolith and N2-physisorption, XRD, SEM, TEM were employed to characterize its textural properties. Subsequently, we used the isovolumetric impregnation method to load different amount of Co3O4-Ce O2 mixed oxide on SM. In addition, the powder Co3O4-Ce O2 mixed oxide was also prepared by the sol-gel method. N2-physisorption, XRD, SEM, EDS, TEM, XPS, H2-TPR and O2-TPD were applied to characterize the supported catalysts(n-Co Ce/SM) and Co3O4-Ce O2. The preparation method of supported catalyst was simplified. We tried to introduce cerium nitrate and cobalt nitrate directly to SM during its preparation process. The soot oxidation activities of one-pot synthesized catalysts were evaluated and the characterizations were also conducted.Based on the above research, we conclude:(1) For the supported catalysts, when the mass ratio of Co3O4-Ce O2 to SM is 2, namely, the n value equals two, the catalyst shows the best activity. This is because the Co3O4-Ce O2 mixed oxide is highly dispersed on the SM and which further generate enough amount of active sites. In addition, the 3D net-linked structure of SM can efficiently capture the soot particles which can make the contact between the soot and catalyst more sufficiently and further improve the catalytic activity.(2) For the monolithic catalyst prepared by one-pot method, the n value equals one, the catalyst shows the best activity, but the catalytic activities of monolithic catalysts are all inferior to the supported catalysts. The reasons may be as follows: the actual mass of active component in monolithic catalyst is lower than the theoretical value; besides, the active component of monolithic catalyst is mainly restricted in the mesopores which is not benefit for the contact between the soot and active site.