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采用溶液浸渍法将乙酰丙酮锰或硝酸锰的糠醇溶液分别灌注到SBA-15的孔道内,一定条件下将糠醇碳化后再将碳烧除,即可得到高度分散的MnxOy/SBA-15复合催化剂.用X射线衍射、透射电镜和N2吸附-脱附等手段对样品进行了表征.结果表明,SBA-15负载MnxOy后,不仅依然保持高度有序的孔道结构、较大比表面积和孔容,而且MnxOy在SBA-15孔道内部高度分散.乙苯的催化氧化反应结果表明,该催化剂尤其是用乙酰丙酮锰做锰源时具有很高的催化活性和选择性. 相似文献
63.
Synthesis of large-pore SBA-15 silica using poly(ethylene oxide)-poly(methyl acrylate) diblock copolymers 总被引:1,自引:0,他引:1
Liang Cao Hongchen Dong Liang Huang Krzysztof Matyjaszewski Michal Kruk 《Adsorption》2009,15(2):156-166
Poly(ethylene oxide)-poly(methyl acrylate) diblock copolymers with narrow molecular weight distributions were synthesized
using atom transfer radical polymerization. The copolymers were used as micellar templates for the synthesis of mesoporous
silicas. The products were characterized using small-angle X-ray scattering, transmission electron microscopy (TEM) and nitrogen
adsorption. The obtained silicas exhibited two-dimensional hexagonal structures of cylindrical mesopores, and thus can be
classified as SBA-15 silicas. In some cases, the size of ordered domains was very small. The (100) interplanar spacings were
13–17 nm, depending on the size of the diblock copolymer used and on the synthesis conditions. Nitrogen adsorption showed
that the silicas exhibited specific surface areas of 350–800 m2 g−1, pore volumes ∼1 cm3 g−1, and narrow pore size distributions. The BJH (nominal) pore diameters were up to ∼20 nm, but actual diameters of cylindrical
pores are expected to be somewhat smaller. In many cases, the mesopores exhibited constrictions. 相似文献
64.
Highly ordered SBA-15 nanoporous silica containing ethylene, phenylene bridges or/and amine, thiol, vinyl and phenyl surface
groups were synthesized by using amphiphilic block copolymer as the structure-directing agent. The XRD data shows high degree
of the order of the final structures. Obtained materials have well-developed porous structure—values of specific surface area
are in the range 700–1050 m2/g and the sizes of cylindrical mesopores are in the range 6.5–9.5 nm. It was determined that size of the mesopores strongly
depends even on small amounts of co-monomers co-condensing with TEOS. A new technique to introduce some amount of pendant
amine groups by co-condensation of proper monomers has been proposed. Tetragonal structure was obtained when small amount
of vinyl groups was introduced to the system. A new approach of determining pore size based only on the XRD measurements was
compared with KJS method, confirming full usefulness of the former for calculation of the size of mesopores in SBA-15 materials.
Dedicated to Professor Mietek Jaroniec on the occasion of his 60th birthday. 相似文献
65.
Z.?Gabelica A.?Charmot R.?Vataj R.?Soulimane J.?Barrault S.?ValangeEmail author 《Journal of Thermal Analysis and Calorimetry》2009,95(2):445-454
Nanometric Fe2O3 particles could be inserted inside the internal pore volume of SBA-15 mesoporous silica and mesoporous alumina supports,
when Fe(III) chelates (EDTA, gluconate or citrate) were used as impregnating precursors. The oxidative degradation of the
chelating anions was followed by combined TG-DTA. Strong chelate-SiOH interactions (case of bulky EDTA), favored by the mesopore
curvature, yield sub-nanometric extremely well dispersed Fe2O3 particles preferentially located at the micropore mouths (confinement effect). Fe2O3 even more strongly interacts with alumina walls, generating either (Fe,Al)2O3 mixed phases or Fe-aluminate micro domains. These iron-based mesoporous alumina composites proved very active catalysts in
total oxidation of phenol at ambient conditions, with extremely low iron leaching (0.2%). 相似文献
66.
采用循环伏安法和碳糊电极, 考察了用共缩合法和二次嫁接法合成的多金属氧酸盐(POM)/SBA-15介孔杂化材料的电化学性质以及氧化还原性能. 在乙腈介质和所检测的电势范围内, 溶液中游离的 物种和浸渍负载于介孔氧化硅上的同样POM物种显示两对WVI单电子氧化还原峰; 共价键联于介孔氧化硅上的 物种也显示两对峰, 但第一对峰的峰电流增大, 还原电位比浸渍样品正移, 表明共价键联的POM不仅能够保持其原有的氧化还原性能, 而且比浸渍负载的POM具有更强的氧化性. 峰流~扫速的关系显示, 在低扫速时, 样品的氧化还原过程是表面控制的; 在高扫速时, 则是扩散控制的. 另外, 钨磷酸盐样品的氧化性大于钨硅酸盐样品; 共缩合法和二次嫁接法合成的样品具有相似的电化学行为. 相似文献
67.
以三嵌段共聚物P123为模板剂, 正硅酸乙酯为硅源, 水热合成了介孔分子筛SBA-15, 通过对SBA-15内外表面修饰, 使用银氨溶液和硝酸银溶液作为金属源合成Ag/SBA-15, 透射电镜(TEM)研究表明在SBA-15孔道内较好地分散了颗粒状和棒状的Ag纳米粒子. 以苯硫酚作为探针分子, 研究了负载Ag纳米粒子的SBA-15的SERS效应, 结果表明Ag/SBA-15具有良好的SERS活性. 另外, 该材料对催化硼氢化钠还原对硝基苯酚具有良好的催化效果, 通过结合现场SERS技术, 研究了该催化过程的机理. 相似文献
68.
Yongzheng Duan Yuming Zhou Yiwei Zhang Xiaoli Sheng Shijian Zhou Zewu Zhang 《天然气化学杂志》2012,21(2):207-214
The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 (AlSBA-15) and alumina-modified SBA-15 (Al2O3/SBA-15), for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al(OC3H7)3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al(OC3H7)3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support. 相似文献
69.
采用逐层负载-孔道内氨/水蒸气原位羟化法制备了一系列负载型钙钛矿La0.8Sr0.2MnO3/SBA-15催化剂,用XRD、BET、TG-DTG、XPS、H2-TPR等手段对催化剂的物性结构等进行了表征,并在常压连续流动固定床反应器上评价了该催化剂对甲苯催化燃烧的催化性能。结果表明,逐层负载-孔道内氨/水蒸气原位羟化法的使用有助于活性组分La0.8Sr0.2MnO3进入SBA-15的孔道,并在SBA-15上形成钙钛矿结构。La0.8Sr0.2MnO3/SBA-15上钙钛矿结构的形成和晶格氧的出现,可为催化剂提供较多的活性中心,有利于其催化燃烧甲苯的活性。 相似文献
70.
高温下自生压力原位碳化制取介孔碳 总被引:1,自引:1,他引:0
以不同配比表面活性剂为软模板合成as-SBA-15, 将其在特制高压釜内, 通过高温自生压力反应(RAPET)使表面活性剂软模板在SBA-15的孔道内原位碳化, 得到碳/介孔二氧化硅复合物, 表面活性剂同时作为模板剂和碳源. 用氢氧化钠溶液腐蚀二氧化硅后得到多孔碳. 氮气吸附脱附测试结果表明, 所得到的碳材料具有较高的比表面积和较窄的孔径分布. 在氮气氛围下煅烧as-SBA-15可使表面活性剂模板挥发. 相似文献