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Molecular Sieves (molecular + sieve)
Selected AbstractsInnentitelbild: Ionothermal Synthesis of an Aluminophosphate Molecular Sieve with 20-Ring Pore Openings (Angew. Chem.ANGEWANDTE CHEMIE, Issue 31 201031/2010) Das kristalline Aluminophosphat-Molekularsieb mit den bislang größten Porenöffnungen (20MR), DNL-1, wurde synthetisiert. In ihrer Zuschrift auf S. 5495,ff. beschreiben Z. Tian et,al. die Ionothermalsynthese von DNL-1 und dessen Strukturbestätigung durch Rietveld-Verfeinerung der PXRD- und NMR-Analyse. Anders als das Zeolithanalogon von Gallophosphat, Cloverit, ist DNL-1 ausgezeichnet stabil, was einen Einsatz für Trennungen, Katalysen und zur Gasspeicherung möglich machen könnte. [source] Ionothermal Synthesis of an Aluminophosphate Molecular Sieve with 20-Ring Pore Openings,ANGEWANDTE CHEMIE, Issue 31 2010Ying Wei Aufnahmebereit: Das erste Aluminophosphat-Molekularsieb mit 20-gliedrigen Porenöffnungen wurde durch Ionothermalsynthese in Gegenwart zweier Strukturbildner erhalten (siehe Bild; H,weiß, C,türkis, N,blau). Das Material verfügt über ein viel stabileres -CLO-Gerüst als sein GaPO4 -Analogon Cloverit, was Anwendungsmöglichkeiten in Trennverfahren, Katalyse und Gasspeicherung eröffnen könnte. [source] A Rational Approach to the Ionothermal Synthesis of an AlPO4 Molecular Sieve with an LTA-Type Framework,ANGEWANDTE CHEMIE, Issue 27 2010Gesunde Struktur: Bei der Synthese eines AlPO4 -LTA-Zeoliths in ionischen Flüssigkeiten fungieren 1-Benzyl-3-methylimidazolium-, Tetramethylammonium- und Fluoridionen als Strukturbildner für die ,-Käfige, Sodalith-Käfige und würfelförmigen Baueinheiten (siehe Bild; C,grau, N,blau, O,rot, Al und P,pink, F grün). Selektives Entfernen der 1-Benzyl-3-methylimidazolium-Ionen ergab ein stabiles AlPO4 -LTA-Molekularsieb. [source] ChemInform Abstract: Double Michael Addition of Dithiols to Acetylenic Carbonyl Compounds under the Influence of Molecular Sieve and Dimethyl Sulfoxide.CHEMINFORM, Issue 17 2010Tomoko Kakinuma Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Molecular Sieve (MS 4A) Promoted Cyclocondensation of Hindered, Aromatic Nitrile Oxides and Cyclic Diketones under Mild Conditions.CHEMINFORM, Issue 2 2004Tomoo Matsuura Abstract For Abstract see ChemInform Abstract in Full Text. [source] Efficient Synthesis of ,-Glycosphingolipids by Reaction of Stannylceramides with Glycosyl Iodides Promoted by TBAI/AW 300 Molecular SievesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2010José Antonio Morales-Serna No abstract is available for this article. [source] Efficient Synthesis of ,-Glycosphingolipids by Reaction of Stannylceramides with Glycosyl Iodides Promoted by TBAI/AW 300 Molecular SievesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2009José Antonio Morales-Serna Abstract TBAI and acid-washed molecular sieves efficiently promoted the glycosylation of stannylceramides with glycosyl iodides. This direct glycosylation reaction reduces the overall number of synthetic steps and provides rapid access to ,-glycosphingolipids such as GalCer, ,-lactosylceramide, and iGB3 in good yield and with complete chemo- and stereoselectivity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] ChemInform Abstract: Synthesis of Methyl 2-Methylazulene-3-carboxylate in the Presence of Molecular Sieves and Reaction with N-Bromosuccinimide.CHEMINFORM, Issue 31 2008Dao-Lin Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Preparation of Deuterium Labelled Organophosphonium Salts (Wittig Salts) under Hydrothermal Condition Catalyzed by Molecular Sieves.CHEMINFORM, Issue 49 2004Mitsuru Yamamoto Abstract For Abstract see ChemInform Abstract in Full Text. [source] Heterogeneous Catalytic Transfer Hydrogenation of Aromatic Nitro and Carbonyl Compounds over Cobalt(II) Substituted Hexagonal Mesoporous Aluminophosphate Molecular Sieves.CHEMINFORM, Issue 6 2003Susanta K. Mohapatra Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Critical Importance of Molecular Sieves in Titanium(IV),Calix[4]arene Catalyzed Epoxidation of Allylic Alcohols.CHEMINFORM, Issue 23 2001Antonio Massa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of Phenazine 5,10-Dioxides from Benzofuroxan Catalyzed by Molecular Sieves.CHEMINFORM, Issue 6 2001Tohru Takabatake Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Molecular sieves in the nanotechnology eraAICHE JOURNAL, Issue 4 2002Michael Tsapatsis First page of article [source] Magnetic Multi-Functional Nano Composites for Environmental ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Jie Dong Abstract A novel concept is proposed to synthesize a new class of composites featuring magnetic, molecular sieve and metallic nanoparticle properties. These multi-functional materials have potential applications as recyclable catalysts, disinfectants and sorbents. The magnetic property enables effective separation of the spent composites from complex multiphase systems for regeneration and recycle, safe disposal of the waste and/or recovery of loaded valuable species. The zeolite molecular sieve provides a matrix which supports a remarkably new, simple, efficient and economical method to make stable, supported silver nanoparticles by silver ion exchange and controlled thermal reduction. The silver nanoparticles generated in this way have excellent properties such as high reactivity and good thermal stability without aggregation, which act as nano reactors for desired functionality in a wide range of applications. Magnetic component (Fe3O4), molecular sieve matrix (zeolite) and silver nanoparticles generated by ion exchange followed by controlled reduction, together form this unique novel composite with designed functions. It represents a practically operational, economical, sustainable and environmentally friendly new advanced functional material. This paper focuses on the novel synthesis and characterization of the composite, with an example of applications as sorbents for the removal of vapor-phase mercury from the flue gas of coal-fired power plants. [source] Hydrothermal Synthesis of Structure- and Shape-Controlled Manganese Oxide Octahedral Molecular Sieve NanomaterialsADVANCED FUNCTIONAL MATERIALS, Issue 9 2006W.-N. Li Abstract Highly uniform single-crystal Na-OMS-2 (OMS: octahedral molecular sieve), pyrolusite, and ,-MnO2 nanostructures with an interesting 3D urchinlike morphology have been successfully prepared using a hydrothermal method based on a mild and direct reaction between sodium dichromate and manganese sulfate. The crystal phases, shapes, and tunnel sizes of the manganese dioxide nanostructures can be tailored. Reaction temperature, concentrations of the reactants, and acidity of the solution play important roles in controlling the synthesis of these manganese dioxides. Field-emission scanning electron microscopy and transmission electron microscopy (TEM) studies show that the nanomaterials obtained are constructed of self-assembled nanorods. X-ray diffraction and TEM results indicate that the constituent manganese dioxide particles are single-crystalline materials. Energy dispersive X-ray analysis and magnetic studies imply that chromium cations may be incorporated into the framework and/or tunnels of the manganese dioxides. A mechanism for the growth of manganese dioxides with urchinlike architectures is proposed. [source] Direct Synthesis of Highly Stable Mesoporous Molecular Sieves Containing Zeolite Building Units,ADVANCED FUNCTIONAL MATERIALS, Issue 2 2005A. Sakthivel Abstract A novel, one-step synthesis of a highly stable mesoporous molecular sieve (MMS-H), which has a structure analogous to MCM-48 but which contains zeolite building units, is reported. A variety of experimental techniques,X-ray diffraction (XRD), N2 adsorption/desorption, transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, hyperpolarized 129Xe,NMR, and solid-state 27Al and 31P,magic-angle spinning (MAS) NMR spectroscopies,have been used to characterize the framework structure, porosity, and acidity of this novel mesoporous/microporous composite material, which is also found to possess superior thermal, hydrothermal, steam, and mechanical stabilities. [source] Properties and application of poly(methacrylic acid- co -dodecyl methacrylate- cl - N,N -methylene bisacrylamide) hydrogel immobilized Bacillus cereus MTCC 8372 lipase for the synthesis of geranyl acetateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Madan Lal Verma Abstract A range of fatty acid esters is now being produced commercially with immobilized microbial lipases (glycerol ester hydrolases; EC) in nonaqueous solvents. In this study, a synthetic hydrogel was prepared by the copolymerization of methacrylic acid and dodecyl methacrylate in the presence of a crosslinker, N,N -methylene bisacrylamide. A purified alkaline thermotolerant bacterial lipase from Bacilluscereus MTCC 8372 was immobilized on a poly(methacrylic acid- co -dodecyl methacrylate- cl - N,N -methylene bisacrylamide) hydrogel by an adsorption method. The hydrogel showed a 95% binding efficiency for the lipase. The bound lipase was evaluated for its hydrolytic potential toward various p -nitrophenyl acyl esters with various C chain lengths. The bound lipase showed optimal hydrolytic activity toward p -nitrophenyl palmitate at a pH of 8.5 and a temperature of 55°C. The hydrolytic activity of the hydrogel-bound lipase was enhanced by Hg2+, Fe3+, and NH ions at a concentration of 1 mM. The hydrogel-bound lipase was used to synthesize geranyl acetate from geraniol and acetic acid in n -heptane. The optimization of the reaction conditions, such as catalyst loading, effect of substrate concentration, solvent (n -pentane, n -hexane, n -heptane, n -octane, and n -nonane), reaction time, temperature, molecular sieve (3 Å × 1.5 mm) and scale up (at 50-mL level), was studied. The immobilized lipase (25 mg/mL) was used to perform an esterification in n -alkane(s) that resulted in the synthesis of approximately 82.8 mM geranyl acetate at 55°C in n -heptane under continuous shaking (160 rpm) after 15 h when geraniol and acetic acid were used in a ratio of 100 : 100 mM. The addition of a molecular sieve (3 Å × 1.5 mm) to the reaction system at a concentration of 40 mg/mL in reaction volume (2 mL) resulted in an increase in the conversion of reactants into geranyl acetate (90.0 mM). During the repetitive esterification under optimum conditions, the hydrogel-bound lipase produced ester (37.0 mM) after the eighth cycle of reuse. When the reaction volume was scaled up to 50 mL, the ester synthesized was 58.7 mM under optimized conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Properties of poly(AAc- co -HPMA- cl -EGDMA) hydrogel-bound lipase of Pseudomonas aeruginosa MTCC-4713 and its use in synthesis of methyl acrylateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Shamsher Singh Kanwar Abstract Microbial lipases (E.C. 3.1.1.3) are preferred biocatalysts for the synthesis of esters in organic solvents. Various extracellular thermoalkaliphilic lipases have been reported from Pseudomonas sp. In the present study, a purified alkaline thermoalkalophilic extracellular lipase of Pseudomonas aeruginosa MTCC-4713 was efficiently immobilized onto a synthetic poly(AAc- co -HPMA- cl -EGDMA) hydrogel by adsorption and the bound lipase was evaluated for its hydrolytic potential towards various p -nitrophenyl acyl esters varying in their C-chain lengths. The bound lipase showed optimal hydrolytic activity towards p -nitrophenyl palmitate (p -NPP) at pH 8.5 and temperature 45°C. The hydrolytic activity of the hydrogel-bound lipase was markedly enhanced by the presence of Hg2+, Fe3+, and NH salt ions in that order. The hydrogel-immobilized lipase (25 mg) was used to perform esterification in various n -alkane(s) that resulted in , 84.9 mM of methyl acrylate at 45°C in n -heptane under shaking (120 rpm) after 6 h, when methanol and acrylic acid were used in a ratio of 100 mM:100 mM, respectively. Addition of a molecular sieve (3Å × 1.5 mm) to the reaction system at a concentration of 100 mg/reaction vol (1 mL) resulted in a moderate enhancement in conversion of reactants into methyl acrylate (85.6 mM). During the repetitive esterification under optimum conditions, the hydrogel-bound lipase produced 71.3 mM of ester after 10th cycle of reuse. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 183,191, 2007 [source] Reliable production of highly concentrated bioethanol by a conjunction of pervaporation using a silicone rubber sheet-covered silicalite membrane with adsorption processJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2004Toru Ikegami Abstract For the production of highly concentrated bioethanol by pervaporation using an ethanol-permselective silicalite membrane, pervaporation performance was investigated using a silicalite membrane entirely covered with a silicone rubber sheet to prevent direct contact with acidic compounds. By using a resistance model for membrane permeation, the separation factor of the covered silicalite membrane towards ethanol can be estimated from the individual pervaporation performances of the silicalite membrane and the silicone rubber sheet. No decrease in the ethanol concentration through the silicone rubber sheet-covered membrane was caused when ethanol solutions containing succinic acid were supplied. By directly passing the permeate-enriched ethanol vapor mixed with water vapor through a dehydration column packed with a molecular sieve of pore size 0.3 nm, highly concentrated bioethanol up to 97% (w/w), greater than the azeotropic point in the ethanol/water binary systems, can be obtained from 9% (w/w) fermentation broth. Copyright © 2004 Society of Chemical Industry [source] Separation of mono- and dibranched hydrocarbons on silicaliteAICHE JOURNAL, Issue 9 2002E. Jolimaitre Breakthrough curves for mixtures of C5 and C6 hydrocarbons with different degrees of branching were obtained experimentally on a silicalite molecular sieve by fixed-bed experiments. The kinetic separation of di- from monobranched hydrocarbons was feasible on this type of zeolite: dimethyl molecules enter silicalite crystals very slowly, whereas monomethyl molecules are quickly adsorbed. Experimental results were compared to a theoretical isothermal model, considering the variation of diffusivity with concentration according to the Maxwell,Stefan theory. The parameters of the model (adsorption equilibria and diffusivities) were determined from single-component breakthrough curves. Experimental curves were generally well represented by the model, but the variation of diffusivity with concentration, as predicted by the Maxwell,Stefan theory, did not significantly improve the model prediction of experimental breakthrough curves by using a mean value of diffusivity. [source] Claudin-5 is Restricted to the Tight Junction Region of Uterine Epithelial Cells in the Uterus of Pregnant/Gravid Squamate ReptilesTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 5 2008Joanna M. Biazik Abstract Claudin-5, a tight junctional protein associated with ion and size selectivity, has been found in the uterus of skinks. This study has generated critical information about the molecular assembly of the tight junction at various stages of the reproductive cycle in the skink uterus. Recent studies looking at tight junctional proteins found occludin expression in the tight junction region of uterine epithelial cells in the skink uterus; however, occludin did not disclose any further information about the ions and size of ions permeating across the paracellular pathway. A ,22-kDa claudin-5 band was detected in the uterus of the skinks present in this study and immunohistochemistry revealed that claudin-5 redistributes to the tight junction region of the lateral plasma membrane of uterine epithelial cells in late stage pregnancy/gravidity. This finding indicates that the tight junction becomes more assembled to precisely regulate ion and solute permeation in late stage pregnancy/gravidity. Claudin-5 with its functional role as a molecular sieve due to the formation of ion and size selective pores suggests that permeation of ions smaller than 0.8 kDa are restricted when claudin-5 is redistributed to the tight junction region of the later plasma membrane. This report is the first description of the molecular mechanisms that may be involved in regulating nutrient provision in the reptilian uterus. Anat Rec, 291:547,556, 2008. © 2008 Wiley-Liss, Inc. [source] Equilibrium and heat of adsorption of phosphine on CaCl2 -modified molecular sieveASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Qiongfen Yu Abstract Adsorption characteristics of the virgin and CaCl2 -immersed molecular sieves at 298 K were investigated to select the adsorbent with high adsorption capacity to phosphine. Adsorption isobars and adsorption isotherms over the phosphine partial pressure and temperature ranged 0 , 1000 Pa and 298 , 343 K were measured. The adsorption equilibrium data for phosphine at various temperatures were fitted to Langmuir and Freundlich isotherm models and their isosteric heats of adsorption were determined by the Clausius-Clapeyron equation. It was found the Freundlich was more suitable for description of phosphine adsorption process through calculating average absolute relative error, and the fitted result about Langmuir model showed the heterogeneous characteristics of modified adsorbent. The isosteric heat of adsorption was about 15 kJ/mol, which indicated adsorptive phosphine removal performance may be a dominant of physical adsorption being easy for desorption. The isosteric heat of adsorption decreased with an increase of the surface loading on CaCl2/5A, which means that CaCl2/5A molecular sieve had an energetically heterogeneous surface. The present study confirmed that the CaCl2/5A molecular sieves would be one of the candidates for separation and recycle of phosphine. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Environmental Properties of Minerals and Contaminants Purified by the Mineralogical MethodACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2004LU Anhuai Abstract The investigation of the environmental properties of minerals, i.e., environmental mineralogy, is a branch of science dealing with interactions between natural minerals and spheres of the Earth surface as well as a reflection of global change, prevention of ecological destruction, participation in biomineralogy, and remediation of environmental pollution. Pollutant treatment by natural minerals is based on the natural law and reflects natural self-purification functions in the inorganic world, similar to that of the organic world , a biological treatment. A series of case studies related to natural self-purification, which were mostly completed by our group, are discussed in this paper. In natural cryptomelane there is a larger pseudotetragonal tunnel than that formed by [MnO6] octahedral double chains, with an aperture of 0.462,0.466 nm2, filled with K cations. Cryptomelane might be a real naturally-occurring mineral of the active octahedral molecular sieve (OMS-2). CrVI -bearing wastewater can be treated by natural pyrrhotite, which is used as a reductant to reduce CrVI and as a precipitant to precipitate CrIII simultaneously. Batch experiments were conducted using the CTMAB-Montmorillonite as an adsorbent for aromatic contaminants (phenol, aniline, benzene, toluene and xylenes), which are detected frequently in the leaching water from municipal waste deposits around China. The CTMAB modification has proved very effective to enhance the adsorption capacity of the sorbent. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside briquettes, and thus brings enough oxygen for combustion and the sulfation reaction. Effective combustion of the original carbon reduces the amount of dust in the fly ash. [source] Facile Method for the Synthesis of Combinatorial Libraries of Benzimidazole, Benzothiazole, Benzoxazole, Perimidine and QuinazolinoneCHINESE JOURNAL OF CHEMISTRY, Issue 2 2009Majid. Abstract A highly yielding and fast method for the synthesis of heterocyclic compounds with trialkyl orthoformate using molecular sieve 3? as a catalyst is described. [source] Stable Tetrahedral Aluminum Sites in Hexagonal Mesoporous AluminosilicatesCHINESE JOURNAL OF CHEMISTRY, Issue 8 2002Yu Han Abstract A unique templating approach for the synthesis of hexagonal mesoporous aluminosilicates via self-assembly of pre-formed aluminosilicate nanoclusters with the templating micella formed by cetyltrimethylammonium bromide (CTAB) is described. The obtained materials of MAS-5 are hydrothermally stable, which is shown by X-ray diffraction (XRD) analysis. Furthermore, as characterized by NMR technique, MAS-5 has stable tetrahedral aluminum sites that is the major contributions to the acidity of aluminosilicate molecular sieve, and on non-framework aluminium species in the samples was observed. [source] Low Potential Detection of NADH at Titanium-Containing MCM-41,Modified Glassy Carbon ElectrodeELECTROANALYSIS, Issue 5 2007Zhihui Dai Abstract Titanium-containing MCM-41 (Ti-MCM-41) modified glassy carbon electrode (GCE) can exhibit an excellent electrocatalytic activity towards the oxidation of ,-Nicotinamide adenine dinucleotide (NADH). A dramatic decrease in the over-voltage of NADH oxidation reaction is observed at 0.28,V (vs. SCE). The modified electrode is found to be stable and reproducible. The electrode shows a linear response for a wide range of 10,1200,,M NADH and the detection limit is 8.0,,M. Ti-MCM-41 mesoporous molecular sieves provide an efficient matrix for development of NADH biosensors and the prepared electrode not only can be used to detect the concentration of NADH in biochemical reaction, but also as the potential matrix of the construction of dehydrogenases biosensor. [source] Decreasing effective nanofluidic filter size by modulating electrical double layers: Separation enhancement in microfabricated nanofluidic filtersELECTROPHORESIS, Issue 23 2008Hansen Bow Abstract Conventional methods for separating biomolecules are based on steric interactions between the biomolecules and randomly oriented gel fibers. The recently developed artificial molecular sieves also rely on steric interactions for separation. In this work, we present an experimental investigation of a method that can be used in these sieves to increase separation selectivity and resolution. This method exploits the electrostatic repulsion between the charged molecules and the charged nanofluidic structure. Although this method has been mentioned in the previous work, it has not been examined in detail. We characterize this method by comparing the selectivity with that achieved in devices with different dimensions. The results of this study are relevant to the optimization of chip-based gel-free biomolecule separation and analysis. [source] Effective Oxidation of Secondary Amines to Nitrones with Alkyl Hydroperoxides Catalysed by (Trialkanolaminato)titanium(IV) ComplexesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2010Massimiliano Forcato Abstract The effective catalytic oxidation of secondary amines to nitrones with alkyl hydroperoxides as the primary oxidants is described. The titanium alkoxide catalysts are protected from the water co-product by the combined use of a tightly binding trialkanolamine ligand and molecular sieves. Nitrones can be obtained in high yields (up to 98,%) under homogeneous, anhydrous conditions and even in the absence of solvent. The reactions are fast (2,7 h) and good selectivity and complete conversion can be achieved with as little as 1,% catalyst. [source] Efficient Synthesis of ,-Glycosphingolipids by Reaction of Stannylceramides with Glycosyl Iodides Promoted by TBAI/AW 300 Molecular SievesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2009José Antonio Morales-Serna Abstract TBAI and acid-washed molecular sieves efficiently promoted the glycosylation of stannylceramides with glycosyl iodides. This direct glycosylation reaction reduces the overall number of synthetic steps and provides rapid access to ,-glycosphingolipids such as GalCer, ,-lactosylceramide, and iGB3 in good yield and with complete chemo- and stereoselectivity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Titanium Containing ,-MnO2 (TM) Hollow Spheres: One-Step Synthesis and Catalytic Activities in Li/Air Batteries and Oxidative Chemical ReactionsADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Lei Jin Abstract Titanium containing ,-MnO2 octahedral molecular sieves having hollow sphere structures are successfully prepared for the first time using a one-step synthesis method. Titanium cations are used as structure-directing agents in the synthesis process. The assembly of the hollow spheres is carried out at the beginning of the process. Various techniques including XRD, N2 adsorption, SEM, EDX, RAMAN, TEM, XPS, and TGA are employed for the materials characterization. Ti is incorporated into the MnO2 framework in isolated sites, and TiO2 phases (anatase and rutile) are not observed. When introduced in medium-sized lithium-air batteries, the materials give very high specific capacity (up to 2.3 A h g,1). These materials are also catalytically tested in the oxidation of toluene with molecular oxygen at atmospheric pressure, showing significant oxidative catalytic activities in this difficult chemical reaction. [source] | ||||||||||||||||||||||||||||||||||