| With the rapid development of domestic economy and the continuous improvement of living standards, the deteriorating environment has attracted wide attention all around the world. Nitrogen oxides as one of the major air pollutants, has a great deal of harm to humans health and the environment. Selective catalytic reduction (SCR) of NOx by ammonia is considered as one of the most efficient and economic technologies for the removal of NOx. Now, the research and development of high efficiency catalyst for SCR reaction has been a top priority.Conversional SBA-15displaying highly curved mesochannels, brings about large diffusion lengths and pore blockage, which are commonly undesirable for catalytic purpose. To overcome these drawbacks, synthesising short-pore SBA-15material with platelet morphologies through hydrothermal routes without addition of mineral acids is proposed. The effect of Ce-doped catalyst on the activity performance was studied. Besides, copper species was incorporated into platelet SBA-15and conventional fibrous SBA-15via incipient wet impregnation to appraise the single influence of pore lengths in SBA-15materials over the dispersion and catalytic activity of copper species. Furthermore, the chemical reaction kinetics of NH3-SCR over short-pore catalysts was briefly studied. The results showed that:(1) The XRD, BET, SEM, TEM, and H2-TPR were used to characterize the catalysts. The result implied that the preparation methods have no influence on the morphologies and mesoporous structure of the supports. The Ce-doped was beneficial to low the crystallinity of catalysts and enhance the redox property. In the selective catalytic reduction of NO, the oxygen storage capacity and surface acidity of catalysts were improved by the introduction of Ce, which would also be beneficial to its activitation especially in the low temperature.(2) The different morphologies and mesostructure were maintained after the incorporation of copper species. Bulk CuO particles were formed on fibrous SBA-15, which showed showed a cavitation phenomenon due to a significant pore blockage. Besides, as confirmed in chemisorptions profiles, pore length affected not only the attained metal dispersion but also the redox property. XPS results showed that the higher Cu2+ratio might improve the surface acidity and favor the adsorption of NO.(3) Compared to the conventional CuO/SBA-15_L catalysts, the application of short-pore CuO/SBA-15_S significantly enhanced catalytic performance, which is ascribed to short-pore support facilitating the metal dispersion and more active sites. Through the study of different reaction conditions, it implied CuO/SBA-15_S processed a wider reaction temperature window. GHSV is of prominent importance in the catalytic activity, and the catalytic activity decreased with the increase of the GHSVs. Furthermore, under the reaction condition of [NO]=500ppm、[NH3]/[NO]=1.1, O2=3%, GHSV=24000h-1,the catalysts reached the maximum NO conversion.(4) Finally, the reaction kinetics of CuO/SBA-15_S was studied. When O2concentration was less than1%, the reaction fulum was kNO={166541exp[36900/(RT)]}[NO]1.2005[O2]1.1057the impact on NO conversion rate could be ignored when O2concentration was more than1%, and the reaction series of O2was0. Then, the reaction folum was KNO={166541exp[36900/(RT)]}[NO]1.2005. In terms of the remarkable changes in apparent activation energy (Ea), it was demonstrated that NO reduction over CuO was significantly structure-sensitive. The internal and external diffusion had less effect on the catalyst performance which could be neglected. |
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