排序方式: 共有388条查询结果,搜索用时 765 毫秒
81.
Chueh-Yang Liu Chia-Fu Chen Jih-Peng Leu Yi-Chun Lin 《Journal of Sol-Gel Science and Technology》2007,43(1):47-51
Direct hydrothermal method is employed for incorporating iron into the pore structure of SBA-15. The resultant materials were
analyzed by X-ray diffraction (XRD) patterns, N2 sorption isotherm and X-ray photoelectron spectroscopy (XPS). The characterizations of XRD patterns and XPS revealed that
iron nanoparticles were present as highly dispersed nanoclusters in the well-ordered mesoporous channels of SBA-15. The characterizations
of t-plot reveal only microporous channels of SBA-15 are confirmed to be filled with iron nanoparticles, leaving the mesopores
unaffected. The supported material still maintained its ordered mesoporous structure similar to SBA-15 and possessed high
surface area, large pore volume and uniform pore size. 相似文献
82.
介孔材料氨基表面修饰及其对CO2的吸附性能 总被引:15,自引:0,他引:15
采用接枝方法在介孔材料MCM-41和SBA-15的孔道内表面进行氨基化修饰, XRD、29Si-NMR、FT-IR、TGA、BET等测试结果表明, 氨丙基三乙氧基硅烷(APTS)和氨乙基氨丙基甲基二甲氧基硅烷(AEAPMDS)都分别接枝在介孔材料的孔道内, 表面氨基修饰量约为1.5-2.9 mmol·g-1. 表面修饰后介孔材料的孔道仍高度有序, 但比表面积减小. 表面修饰前后介孔材料对CO2的吸附性能发生显著变化, 由于物理吸附转化为以氨基为活性中心的化学吸附, 吸附量从修饰前的0.67 mmol·g-1提高到2.20 mmol·g-1. 相似文献
83.
Xiaochen Dong Li Wang Guohua Jiang Zhenrong Zhao Tianxu Sun Haojie Yu Wenqin Wang 《Journal of molecular catalysis. A, Chemical》2005,240(1-2):239-244
Under atmospheric pressure, nano-polyethylene fibres were prepared via in situ ethylene extrusion polymerization, with MCM-41 and SBA-15 supported zirconocene dichloride (Cp2ZrCl2) catalytic systems, respectively. The effects of the geometrical structures and surface properties of MCM-41 and SBA-15 on the morphology of the resultant polyethylene, catalytic activity and polymerization rate were investigated and compared in various polymerization conditions. The possible formation mechanism of nano-polyethylene fibres with MCM-41 and SBA-15 supported Cp2ZrCl2 as catalyst was discussed. 相似文献
84.
Protein adsorption on the mesoporous molecular sieve silicate SBA-15: effects of pH and pore size 总被引:1,自引:0,他引:1
A mesoporous molecular sieve silicate, SBA-15, with three pore sizes (38.1 A, 77.3 A, and 240 A) has been synthesized using a non-ionic, tri-block copolymer as a template in a sol-gel method. The effects of synthesis conditions on the pore size and pore-size distribution of this adsorbent have been described. The adsorption of proteins on these crystalline, ordered, materials has been studied. The kinetics of adsorption and equilibrium capacity have been probed with three proteins of different dimensions. The effects of electrostatic interactions and protein size are illustrated. It has been shown that SBA-15 materials can be tailored to show size selectivity for proteins, and very high capacities (450 mg/g) can be obtained. Furthermore, the rates of adsorption are shown to be dependent on the pore size, protein structure and solution pH. 相似文献
85.
Shakeel Ahmed 《Reaction Kinetics and Catalysis Letters》2007,90(2):285-291
A series of hydrocracking catalysts based on mesoporous molecular sieves MCM-41 and SBA-15 with different silica to alumina
ratios was prepared. Nickel and molybdenum were used as active metals to impregnate the extrudates prepared by using molecular
sieves. The catalysts were characterized for physical and chemical properties and evaluated for the hydrocraking of desulfurised
vacuum gas oil. The conversion of DS-VGO was lower as compared to that of the catalyst based on USY zeolite. However, the
gas yield was lower in case of mesoporous materials based catalysts. 相似文献
86.
Characterization and Dehydrogenation Activity of SBA-15 and HMS Supported Chromia Catalysts 总被引:2,自引:0,他引:2
IntroductionEnormousstudyhasbeendevotedtoM4 1S ,thefirstfamilyofmesoporousmolecularsievesreportedin1992 ,1,2 includingtheirmodificationsandapplicationsincatalysis .Theattractivepropertiesofthesematerialsaretheirhighspecificsurfacearea (>10 0 0m2 /g) ,well de finedstr… 相似文献
87.
88.
Xianbin Liu Laisheng LiYu Du Zhen GuoTeng Teng Ong Yuan ChenSiu Choon Ng Yanhui Yang 《Journal of chromatography. A》2009,1216(45):7767-7773
A modified synthesis approach for spherical large pore-diameter SBA-15 mesoporous silica (SLP-SBA-15) with particle size range of 0.5–1 μm was being reported. It was worth mentioning that in this improved methodology, the use of cetyltrimethylammonium bromide (CTAB) as co-template significantly reduced the self-assembly time from 24 h to 45 min. Moreover, under reflux condition, the reaction time could be further shortened by reducing the aging time from 48 h to 6 h. The resultant SLP-SBA-15 was thereafter successfully functionalized and packed into an ultra-high-performance liquid chromatography (UHPLC) column for the separation of aromatic compounds. A variety of characterizations demonstrated that the silica products exhibited a well-ordered 2d hexagonal mesostructure with well-formed spherical morphology. pore-diameter can be enlarged up to 8.2 nm without affecting the structural order. The SLP-SBA-15 samples showed excellent thermal and hydrothermal stabilities. The octadecyltriethoxysilane functionalized SLP-SBA-15 (SLP-C18-SBA-15) was demonstrated to be an effective stationary phase in UHPLC application because the column exhibited significantly reduced column pressure (2800 psi) at a flow rate of 0.4 ml/min. Accordingly, it would afford greater flexibility for tuning of the flow rate to meet the fast separation requirement. 相似文献
89.
Christian Hess 《Surface science》2006,600(18):3695-3701
Nanostructured vanadia model catalysts, i.e., highly dispersed vanadium oxide supported on mesoporous silica SBA-15 (VOx/SBA-15), were prepared. The mechanism for the synthesis of VOx/SBA-15 was elucidated by detailed characterization of the individual synthesis steps using XPS and vibrational spectroscopy. The resulting surface vanadium oxide species (0-2.3 V/nm2), grafted on the inner pores of the SBA-15 silica matrix, consists of tetrahedrally coordinated vanadia as inferred from UV-VIS- and Raman spectroscopy. The prepared vanadia model catalysts were tested in the partial oxidation of methanol to formaldehyde yielding high formaldehyde selectivities of 94% at 350 °C. XPS and Raman analysis of the catalyst after reaction reveal the presence of methoxy as well as a significant amount of carbonaceous species on the surface. Our results demonstrate that a detailed understanding of partial oxidation reactions requires the combination of complementary spectroscopic techniques ultimately within one experimental set-up. 相似文献
90.
Yan-Xia Jiang Jin-Mei Xu Quan-Chao Zhuang Lan-Ying Jin Shi-Gang Sun 《Journal of Solid State Electrochemistry》2008,12(4):353-361
Functionalized molecular sieve SBA-15 with trimethylchlorosilane was used as an inorganic filler in a poly(ethyleneoxide)
(PEO) polymer matrix to synthesize a composite solid-state polymer electrolyte (CSPE) using LiClO4 as the doping salts, which is designated to be used for rechargeable lithium batteries. The methyl group-functionalized SBA-15
(fSBA-15) powder possesses more hydrophobic characters than SBA-15, which improves the miscibility between the fSBA-15 filler and the PEO matrix. The interaction between the fSBA-15 and PEO polymer matrix was investigated by scanning electron microscopy, X-ray diffraction, and differential scanning
calorimetry. Linear sweep voltammetry and electrochemical impedance spectroscopy were employed to study the electrochemical
stability windows, ionic conductivity, and interfacial stability of the CSPE. The temperature dependence of the change of
the PEO polymer matrix in the CSPE from crystallization to amorphous phase was surveyed, for the first time, at different
temperature by Fourier transform infrared emission spectroscopy. It has demonstrated that the addition of the fSBA-15 filler has improved significantly the electrochemical compatibility of the CSPE with a lithium metal electrode and
enhanced effectively the ion conductivity of the CSPE.
Dedicated to Professor Oleg Petrii on the occasion of his 70th birthday on August 24th, 2007. 相似文献