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Journal Cover Microporous and Mesoporous Materials
  [SJR: 1.243]   [H-I: 116]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [3051 journals]
  • On the desiccant capacity of the mesoporous RF-xerogels
    • Authors: Isabel D. Alonso-Buenaposada; Ana Arenillas; J. Angel Menéndez
      Pages: 1 - 6
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Isabel D. Alonso-Buenaposada, Ana Arenillas, J. Angel Menéndez
      Resorcinol-formaldehyde xerogels are ideal desiccant materials since the high concentration of hydroxyl groups on their surfaces confers on them a high hydrophilicity, which adsorbs moisture from their surroundings and their large porosity provides them with a high water sorption capacity. In this study, the porosity of organic xerogels was tailored by adjusting the proportion of methanol in the precursor solution in order to optimize their desiccant capability. It was found that, although an increase in microporosity improves the performance of the desiccant, mesoporosity is a more important property for this application. Organic xerogels are excellent desiccants which are able to adsorb more than 80% of their own weight in moisture and function efficiently for more than 3000 h, when their porosity is optimized. This is a great improvement on the commonly used silica gels that become saturated after only 150 h and can only adsorb a maximum of 40 wt % of their own weight in moisture. Moreover, RF xerogels have the advantage that they are organic materials resistant to acid attack and this allows them to be used in processes where conventional inorganic desiccants would rapidly deteriorate.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.014
      Issue No: Vol. 248 (2017)
       
  • Mesopore modification of beta zeolites by sequential alkali and acid
           treatments: Composition-dependent T-atoms removal behavior back donating
           to hierarchical structure and catalytic activity in benzene alkylation
    • Authors: Yingjie Jin; Li Zhang; Jinhuan Liu; Shudong Zhang; Suhua Sun; Sachio Asaoka; Kaoru Fujimoto
      Pages: 7 - 17
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Yingjie Jin, Li Zhang, Jinhuan Liu, Shudong Zhang, Suhua Sun, Sachio Asaoka, Kaoru Fujimoto
      Acidic zeolites beta with wider Si/Al ratios were desilicated and dealuminated using the alkali–acid treatment approach involving hydrothermal alkali pre–etching. Zeolites beta subjected to mesopore modification were characterized by the techniques of XRD, N2 physisorption, SEM, TEM, EDX, ICP–AES, NH3–TPD, pyridine FTIR adsorption, and immersion porosimetry to examine changes of structural/textural and acidic properties with initial Si/Al ratio. Benzene alkylation with 1-dodecene was used as a model reaction to elucidate the influence of mediated acidity and texturally mesoporous structure on bulky hydrocarbon transformations. The resulting zeolites beta were shown to have hierarchical porous structures and regular mesoporous size distributions. Initial Si/Al ratios appeared to dominate significant mesoporosity development though no clear threshold of initial Si/Al ratio was identified to be more instrumental in forming mesopores. A volumetric fraction of intraparticle to total BJH mesopores proved to reduce with increasing initial Si/Al ratio. The modified zeolites showed more than 95% desilication selectivity whereas less than 5.0% dealumination selectivity upon overall treating processes. T-atoms removal efficiencies relative to areal, volumetric and diametrical factors revealed the coherent characteristics to T-atoms removal selectivities. Moreover, the dependency of benzene alkylation activity on mesopore size distribution was observed from changes of 1-dodecene conversion and LAB selectivity, both of which were promoted by the hierarchical zeolites. Despite both with comparable acidic properties, the typical sample subjected to the combined alkali–acid treatments was shown to have narrowing mesopore size distribution and hence to exhibit the enhanced catalytic performance for selective production of linear alkylbenzenes compared with the purely desilicated sample with broadening mesopore size distribution.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.013
      Issue No: Vol. 248 (2017)
       
  • Sol-gel chemistry, templating and spin-coating deposition: A combined
           approach to control in a simple way the porosity of inorganic thin
           films/coatings
    • Authors: Roberto Nisticò; Dominique Scalarone; Giuliana Magnacca
      Pages: 18 - 29
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Roberto Nisticò, Dominique Scalarone, Giuliana Magnacca
      Porous materials are powerful functional devices that can find applications in many fields, from nanotechnology to biomedicine, from catalysis to membrane separation. In general, porous materials can be processed in various forms, but a rising interest is growing around inorganic thin films and coatings, due to the increased number of applications based on their use. Among the different strategies proposed till now for preparing inorganic porous thin layers/coatings, a simple and versatile route consists in the combined use of sol-gel chemistry, templating, and spin-coating deposition. Therefore, in order to provide a helpful toolbox for users, an extended discussion around the physico-chemical principles behind each of these steps is here reported, also highlighting the advantages and disadvantages of each procedure, together with critical points.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.017
      Issue No: Vol. 248 (2017)
       
  • Fast synthesis of hierarchical Beta zeolites with uniform nanocrystals
           from layered silicate precursor
    • Authors: Gang Huang; Peng Ji; Hao Xu; Jin-Gang Jiang; Li Chen; Peng Wu
      Pages: 30 - 39
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Gang Huang, Peng Ji, Hao Xu, Jin-Gang Jiang, Li Chen, Peng Wu
      Hierarchical Beta zeolite composed of uniform nanocrystals with high pore volume and external surface area was fast synthesized within 4 h at a high yield using layered silicate precursor (H-kanemite) as silica source. The transformation process of layered silicate precursor into Beta zeolite is investigated carefully by XRD, FT-IR, NMR spectroscopies, SEM, and TEM techniques. TEM and SEM images indicated the obtained Beta zeolite is consisted of self-sustaining macrosized zeolitic aggregates assembled from uniform nanosized crystals, and it possesses relatively narrow distributed intercrystal mesopores. The hierarchically structured Beta zeolite, with an enhanced accessibility for bulky molecule to acid sites in the framework, shows better catalytic behaviors in the industrially-relevant Friedel-Crafts acylation reaction in comparison to commercially available or traditional Beta zeolite.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.060
      Issue No: Vol. 248 (2017)
       
  • Adsorptive separation of ethane and ethylene using IsoReticular
           Metal-Organic Frameworks
    • Authors: Francisco D. Lahoz-Martín; Sofía Calero; Juan José Gutiérrez-Sevillano; Ana Martin-Calvo
      Pages: 40 - 45
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Francisco D. Lahoz-Martín, Sofía Calero, Juan José Gutiérrez-Sevillano, Ana Martin-Calvo
      This computational study focuses on the adsorption and diffusion of ethane and ethylene in IsoReticular Metal-Organic Frameworks (IRMOFs). We selected the IRMOFs family for the diversity of linkers, which allows understanding the effect that functionalized groups, ligand length, cyclic groups, or interpenetrating cavities has on the accessible pore volume of the structures and on the selective behavior towards the components of the mixture. At atmospheric pressure and 298 K, we found that the smaller interpenetrated structures (IRMOF-9, -11, and -13) exhibit larger adsorption selectivity than their non-interpenetrated counterparts (IRMOF-10, -12, and 14, respectively). Based on these findings we discuss the advantages of using interpenetrating structures for ethane capture. On the other hand, structures with large pore volume such as IRMOF-16 seem to reverse the adsorption selectivity in favor of ethylene.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.009
      Issue No: Vol. 248 (2017)
       
  • Degradation of core-shell Au@SiO2 nanoparticles in biological media
    • Authors: Elena I. Ryabchikova; Boris P. Chelobanov; Roman G. Parkhomenko; Kseniya V. Korchagina; Tamara V. Basova
      Pages: 46 - 53
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Elena I. Ryabchikova, Boris P. Chelobanov, Roman G. Parkhomenko, Kseniya V. Korchagina, Tamara V. Basova
      In this work, the effect of a cell culture medium on the integrity of mesoporous silica shell of gold-core nanoparticles (Au@SiO2 NPs) and their behavior in cells of HeLa, MDA-MB and BT cultures were studied using the method of transmission electron microscopy. It was shown that degradation of Au@SiO2 NPs takes place in the culture medium. The presence of the cells and serum does not influence on the process of the mesoporous silica layer degradation. The presence of both damaged and undamaged NPs in endosomes and lysosomes is related to different time of NPs' location outside of the cell, i.e. in culture medium. The analysis of the cell ultrastructure leads to a conclusion that the internal conditions in endosomes/lysosomes do not influence on the integrity of Au@SiO2 NPs.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.006
      Issue No: Vol. 248 (2017)
       
  • Confinement effect on ultrafast events of a salicylideneaniline derivative
           within mesoporous materials
    • Authors: Noemí Alarcos; Félix Sánchez; Abderrazzak Douhal
      Pages: 54 - 61
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Noemí Alarcos, Félix Sánchez, Abderrazzak Douhal
      We report on femtosecond (fs) studies of HBA-4NP interacting with MCM41, Al-MCM41 and SBA15 materials, and discuss the dynamics of caged monomers and J-aggregates. For MCM41 and Al-MCM41 composites, and upon excitation at 380 nm (monomers region) the ultrafast dynamics (250 fs and 2.5 ps for HBA-4NP/MCM41, 350 fs and 3.5 ps for HBA-4NP/Al-MCM41) is slower than that observed in solution due to aggregates formation inside the material pores. While exciting at 410 nm, we got a slower behaviour. However, for HBA-4NP/SBA15 composites, with a low loading, where the caged monomers are the main guests, we recorded faster dynamics (200 fs and 2 ps) independently on the pumping wavelength. These results show how the properties of mesoporous materials, especially its pore size and Al-doping, affect the nature of the formed composites and their ultrafast photodynamics.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.04.011
      Issue No: Vol. 248 (2017)
       
  • Hydrogen adsorption of nickel-silica materials: Role of the SBA-15
           porosity
    • Authors: P.M. Carraro; A.A. García Blanco; C. Chanquía; K. Sapag; M.I. Oliva; G.A. Eimer
      Pages: 62 - 71
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): P.M. Carraro, A.A. García Blanco, C. Chanquía, K. Sapag, M.I. Oliva, G.A. Eimer
      In this work, SBA-15 support was impregnated with nickel in order to study the influence of different factors (metal content, support, method of preparation) on their hydrogen storage capacity. H2 adsorption was measured at low and high pressures (up to 10 and 40 bar) at 77 and 293 K, evaluating the influence of metallic nickel on such adsorption capacity. The properties of the prepared materials were studied by N2 adsorption-desorption, XRD, TPR, UV–Vis, TEM, SEM and XPS techniques. The results indicated the importance of the nickel dispersion on the support to improve hydrogen storage. Thus, Ni/SBA-15 (2.5) sample, in contrast to Ni/SBA-15 (2.5)-R, shows the higher hydrogen adsorption capacity at both 77 K and 293 K.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.057
      Issue No: Vol. 248 (2017)
       
  • Modeling hydrogen diffusion in hybrid activated carbon-MIL-101(Cr)
           considering temperature variations and surface loading changes
    • Authors: Zhewei Yu; Johnny Deschamps; Lomig Hamon; Prasanth Karikkethu Prabhakaran; Pascaline Pré
      Pages: 72 - 83
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Zhewei Yu, Johnny Deschamps, Lomig Hamon, Prasanth Karikkethu Prabhakaran, Pascaline Pré
      MIL-101(Cr) and activated carbon (AC) doped MIL-101(Cr) materials were synthesized under mild conditions, avoiding the use of hydrofluoric acid, and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and physisorption. It was shown that the AC doping induced enhancements of the specific surface area and increase in the pore volume of the adsorbent. Hydrogen adsorption isotherms and kinetics were measured at 77 K up to 50 bar by using a volumetric method. A hydrogen uptake of 9.3 wt.% was measured for the hybrid material, which was significantly higher than that for pristine MIL-101(Cr) which reached an uptake of 6.2 wt.% under the same conditions of temperature and pressure. Effective diffusion coefficients were besides attempted to be extracted from experimental kinetic curves, by using the Linear Driving Force (LDF) model in a first approach. However, this model failed to describe correctly the experimental kinetic data as it does not explicitly consider the external mass transfer resistance, neither the temperature nor the surface loading effects on the intra-crystalline diffusion process. To overcome these limitations, a more detailed model was proposed, based on the evaluation of both an external mass transfer coefficient and of an internal surface diffusivity in the adsorbed phase that accounts for the effects of temperature and adsorbent surface coverage. This model was proved to predict well the hydrogen adsorption rates in both the MOF and hybrid AC-MOF material at 77 K, in the pressure range up to 20 bar.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.059
      Issue No: Vol. 248 (2017)
       
  • Investigation of the effect of energy variation and structure change on
           the adsorption of volatile organic compounds in ZIF-8 by a DFT approach
    • Authors: Dejie Li; Ping Zhang; Qi Kang; Ying Han; Dazhong Shen
      Pages: 84 - 90
      Abstract: Publication date: August 2017
      Source:Microporous and Mesoporous Materials, Volume 248
      Author(s): Dejie Li, Ping Zhang, Qi Kang, Ying Han, Dazhong Shen
      The effect of energy variation and structure change on the adsorption of a group of volatile organic compounds including methane, chloromethane, dichloromethane, trichloromethane and carbon tetrachloride (CH4, CH3Cl, CH2Cl2, CHCl3 and CCl4) in zeolitic imidazolate framework-8 was investigated by density functional theory method, focusing on the swing effect implemented by the reorientation of 2-methylimidazole linkers. It was shown that the attachment energy is in the order of CCl4 (−19.5 kJ/mol) < CHCl3 (−17.0 kJ/mol) < CH4 (−16.5 kJ/mol) < CH2Cl2 (−15.4 kJ/mol) < CH3Cl (−13.8 kJ/mol) and the order of diffusion energy barrier is CH4 (3.3 kJ/mol) < CH2Cl2 (6.5 kJ/mol) < CH3Cl (13.5 kJ/mol) < CHCl3 (56.9 kJ/mol). It is hopeful that the characterization of the details of adsorption process on thermodynamics could serve as an important stepping stone for understanding the adsorption process during uptake experiments and therefore illuminate the way of some other ideas such as theoretical explain/prediction on the performance of porous materials.
      Graphical abstract image

      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.029
      Issue No: Vol. 248 (2017)
       
  • Mesoporous silica-based nanotubes loaded Pd nanoparticles: Effect of
           framework compositions on the performance in heterogeneous catalysis
    • Authors: Jing Sun; Hua Wang; Xue Gao; Xinli Zhu; Qingfeng Ge; Xiao Liu; Jinyu Han
      Pages: 1 - 8
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Jing Sun, Hua Wang, Xue Gao, Xinli Zhu, Qingfeng Ge, Xiao Liu, Jinyu Han
      Well-shaped mesoporous silica-based nanotubes with different framework compositions, such as organic groups (ethylene, phenylene), carbon/silica hybrids, could be controllably synthesized with the inner diameter of less than 10 nm and the surface areas of about 400–900 m2 g−1. Through an impregnation-reduction process, palladium (Pd) nanoparticles have been uniformly dispersed in the channels of these different nanotubes, which were confirmed by electron microscopy analysis. The catalytic performance of these silica-based nanotubes loaded Pd nanoparticles was evaluated by the aerobic oxidation of benzyl alcohol and enantioselective hydrogenation of α,β-unsaturated carboxylic acid, respectively. Due to one-dimensional nanotube structures and tunable hydrophilic/hydrophobic properties, the organosilica nanotubes supported Pd nanoparticles could afford >99% conversion of benzyl alcohol and 89% selectivity of benzaldehyde within 2 h. Importantly, carbon/silica hybrid nanotubes may have a positive effect on the reaction, which gave about 95% selectivity of benzaldehyde. The catalysts could be reused without an obvious decrease in both conversion and selectivity. Furthermore, the silica-based nanotubes supported Pd nanoparticles were also efficient for asymmetric hydrogenation of α,β-unsaturated carboxylic acids, which showed a highest conversion of 99% with 48% enantioselectivity.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.040
      Issue No: Vol. 247 (2017)
       
  • Hollow (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes with porous shell synthesized
           via chemical precipitation: A novel form as a high performance lithium ion
           battery anode
    • Authors: Manab Kundu; Gopalu Karunakaran; Evgeny Kolesnikov; Arkhipov Dmitry; Mikhail V. Gorshenkov; Denis Kuznetsov
      Pages: 9 - 15
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Manab Kundu, Gopalu Karunakaran, Evgeny Kolesnikov, Arkhipov Dmitry, Mikhail V. Gorshenkov, Denis Kuznetsov
      Transition metal oxides containing different metal cations, also called as mixed metal oxides (MMOs), have confirmed improved electrochemical activities in comparison with single metal oxides (SMOs, containing single metal cations). In this study, for the first time, we have synthesized the hollow (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes by simple and cost effective chemical precipitation method and investigated its lithium storage property. The uniqueness of this composite material is the hollow nano-structure with a very thin porous shell, which has rarely reported previously. The observed surface area of nanoboxes is 21.8 m2 g−1 with average pore size of 4 nm. As a results, the (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes manifests a high reversible capacity of around 835.5 and 676.2 mAh g−1 over 350 cycles at a current densities of 200 and 500 mA g−1, respectively. The nano-dimention with hollow structure not only benefited electron and Li-ion transportation, it also provided large electrode–electrolyte contact area. Furthermore, the high reversible capacity in (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes electrodes is most likely attributed to the synergistic electrochemical activity of both the phases, (Co0.62Fe1.38)FeO4 and NiCo2O4. Hence, based on high reversible capacity as well as an outstanding rate performance, the (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes electrode sheds light on commercial applications as an alternative lithium-ion battery anode material.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.045
      Issue No: Vol. 247 (2017)
       
  • Effects of crystal size and pore structure on catalytic performance of
           TS-1 in the isomerization of styrene oxide to phenyl acetaldehyde
    • Authors: Xiong-Fei Zhang; Jianfeng Yao; Xiaoxia Yang
      Pages: 16 - 22
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Xiong-Fei Zhang, Jianfeng Yao, Xiaoxia Yang
      In this study, isomerization of styrene oxide to phenyl acetaldehyde was investigated over a series of TS-1 catalysts with different crystal sizes and post-treatment methods under a gas-phase atmosphere free of solvents. The physicochemical properties of the samples were characterized by a combination of N2 adsorption, XRD, NH3-TPD, UV–vis, FT-IR and SEM. By the characterization of catalysts and investigation of their catalytic performances, results indicated that nano size TS-1 exhibited better anti-coking ability and phenyl acetaldehyde selectivity than micro size TS-1. Additionally, TPAOH treatment led to the development of considerable mesoporosity without significant destruction of its intrinsic zeolite properties. The results highlighted that the existence of well-developed hierarchical pore systems in TS-1-O could reduce diffusion path length and enhance transport of phenyl acetaldehyde out of the zeolite crystals, thus markedly improving catalytic stability and selectivity. However, upon NaOH treatment, the micropore structures were irreversibly destroyed accompaning with the amorphization of the zeolite crystals.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.047
      Issue No: Vol. 247 (2017)
       
  • Dual functional hybrid-polyoxometalate as a new approach for multidrug
           delivery
    • Authors: Davud Karimian; Bahram Yadollahi; Valiollah Mirkhani
      Pages: 23 - 30
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Davud Karimian, Bahram Yadollahi, Valiollah Mirkhani
      Herein, a new antitumor active polyoxometalate, (TBA)4H3[GeW9V3O40], has been introduced as an inorganic drug with enormous influence on brain cancer cells and its outstanding results against U87 cells have been described. Post-functionalization of this polyoxometalate produces a drug delivery vehicle which comprises both kinds of inorganic and organic drugs. This system is consisted of mesoporous silica nanoparticles as organic drug carrier, along with redox-responsive disulfide bonds for drug release into the cell at the same time. Moreover, a fluorescence dye has been attached to the polyoxometalate that allows for tracking the drug into the cell environment. This dual-functionalized polyoxometalate was utilized in a designed multidrug delivery system, and worked greatly against U87 cells and knocked down these cancer cells up to near 70% in 48 h. Due to its unique properties, this multidrug delivery vehicle is potent to be developed and used for various applications in cancer therapy.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.048
      Issue No: Vol. 247 (2017)
       
  • Phosphorus modified hierarchically structured ZSM-5 zeolites for enhanced
           hydrothermal stability and intensified propylene production from 1-butene
           cracking
    • Authors: Jian Lv; Zile Hua; Tongguang Ge; Jinlin Zhou; Jian Zhou; Zhicheng Liu; Hangle Guo; Jianlin Shi
      Pages: 31 - 37
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Jian Lv, Zile Hua, Tongguang Ge, Jinlin Zhou, Jian Zhou, Zhicheng Liu, Hangle Guo, Jianlin Shi
      Hierarchically structured ZSM-5 zeolites (HSZ) were synthesized by a mesoporogen-free procedure and subsequently modified with varied amounts of phosphorus (1–3 wt%) through impregnation of phosphoric acid solution. Materials characterization using various techniques showed that the hierarchical structures of HSZ were well preserved after phosphorus modification, and more interestingly, their hydrothermal stability were improved significantly and the main textural properties kept almost unchanged even after hydrothermally treated at 750 °C for 4 h in 100% steam. The strong acid sites of HSZ were found to be gradually eliminated by the phosphorus induced dealumination of tetrahedral framework aluminum (TFAL), however, weak acid sites remained almost intact. In the 1-butene cracking reactions, benefitting from the auxiliary mesopores and phosphorus modification, P-modified HSZ showed remarkably improved selectivity (∼52%) and yield (∼43%) of propylene as well as superior anti-deactivation ability. All these properties of P-modified HSZ made it a promising catalyst for industrial application.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.037
      Issue No: Vol. 247 (2017)
       
  • Humidity sensor based on zeolite for application under environmental
           conditions
    • Authors: G.P. Alcantara; L.E.B. Ribeiro; A.F. Alves; C.M.G. Andrade; F. Fruett
      Pages: 38 - 45
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): G.P. Alcantara, L.E.B. Ribeiro, A.F. Alves, C.M.G. Andrade, F. Fruett
      This work evaluates two different zeolite-based humidity sensors. In the first case, interdigital capacitive sensors (IDC-S) were fabricated on the surface of Al2O3 ceramic substrates, using electrode gaps of 20 μm, and were coated with films of LTA-type (Lind Type A) zeolite with Si/Al ratio of 1.28. Complex impedance spectroscopy (IS) was used to measure the sensor response, which was related to the change in capacitance of the interdigital electrodes and, in turn, to the electrical properties of the zeolites. The zeolite-based sensors were characterized in terms of the effects of changes in humidity and temperature on the sensor response. The results showed that this sensor provided detectable capacitance changes at very low water contents (up to 300 ppmv of H2O in N2), at temperatures ranging from 25 to 100 °C, and was therefore suitable for moisture trace measurements. In the second part of the work, evaluation was made of a humidity sensor based on ZSM-5 (Zeolite Socony Mobil - 5) zeolite. Interdigital capacitive sensors were fabricated on the surface of Al2O3 ceramic substrates, with electrode gaps of 20 μm, and were coated with films of ZSM-5. The results showed that the sensor was capable of good performance (detection limit of ∼7.32% RH) and was suitable for use under a broader range of environmental conditions (∼39% RH - 96% RH), compared to sensors based on other materials such as polyimide (detection limit of 20% RH) and TiO2 (detection limits from 10% to 30% RH).
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.042
      Issue No: Vol. 247 (2017)
       
  • Incorporation of silicon into monodispersed starburst carbon spheres with
           LVD method
    • Authors: Kazuhisa Yano; Narihito Tatsuda; Takashi Masuda; Tatsuya Shimoda
      Pages: 46 - 51
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Kazuhisa Yano, Narihito Tatsuda, Takashi Masuda, Tatsuya Shimoda
      A liquid vapor deposition (LVD) method, in which vapor from a liquid silicon precursor, cyclopentasilane (CPS), is utilized, allows homogeneous incorporation of silicon into mesopores of monodispersed starburst carbon spheres (MSCS). The amount of silicon incorporated can be precisely controlled just by changing the amount of CPS. MSCS consists of carbon nanorods and their surfaces are shown to be coated with silicon. The Si/MSCS is tested for an anode of LIB. It is found to retain a capacity of more than 2000 mAh/g after 100 charging cycles when an appropriate amount of silicon is incorporated into MSCS.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.055
      Issue No: Vol. 247 (2017)
       
  • Xylene separation on a diverse library of exchanged faujasite zeolites
    • Authors: Yoldes Khabzina; Catherine Laroche; Javier Perez-Pellitero; David Farrusseng
      Pages: 52 - 59
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Yoldes Khabzina, Catherine Laroche, Javier Perez-Pellitero, David Farrusseng
      For the first time, a systematic, consistent domain exploration has been conducted on mono- and bi-cationic exchanged X and Y faujasites for xylene separation using a combinatorial approach. In total, a large, diverse library of 68 faujasites exchanged with alkali cations (Na+, K+, Cs+) and alkali earth cations (Ca2+, Ba2+) was prepared and tested in the presence of three distinct mixture conditions of relevance to the separation process. From the measurements of the 68 × 3 breakthrough curves, we calculated separation performances for the three xylene isomers (p-, m-, o-X), EB, and PDEB. The set of performance properties generated for each adsorbent was analyzed by statistical methods enabling sorting into different classes of selective adsorbents. A rational mapping of exchanged faujasites for xylene separation was performed.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.026
      Issue No: Vol. 247 (2017)
       
  • Electrorheological response of mesoporous expanded perlite particles
    • Authors: Mehmet Cabuk
      Pages: 60 - 65
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Mehmet Cabuk
      In this study, chemical composition, structural and physical properties of expanded perlite (EP) were determined by particle size, apparent density, SEM-EDS and XRD measurements. Electrorheological (ER) properties of EP particles dispersed in silicone oil (SO) were fully investigated as a novel dry-based ER fluid. Thus, ER response of EP/SO dispersions was revealed as a function of electric field strength (E), volume fraction, shear rate, shear stress, frequency and temperature. As a result, the EP/SO ER fluid was observed to sensitive to external E, exhibiting a typical shear thinning non-Newtonian viscoelastic behavior. The correlation between the yield stress (τ y ) and E was deviated from polarization model (m < 2). Further, antisedimentation stabilities of the mesoporous EP particles in SO medium were determined to be perfectly suitable for potential ER applications under various temperatures.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.044
      Issue No: Vol. 247 (2017)
       
  • Synthesis of multiple-shelled organosilica hollow nanospheres via a
           dual-template method by using compressed CO2
    • Authors: Xin Huang; Wei Li; Meijin Wang; Xiuniang Tan; Qian Wang; Mengnan Zhang; Cheng Wang; Haifei Zhang
      Pages: 66 - 74
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Xin Huang, Wei Li, Meijin Wang, Xiuniang Tan, Qian Wang, Mengnan Zhang, Cheng Wang, Haifei Zhang
      A facile and sustainable approach for preparation of multiple-shelled hollow periodic mesoporous organosilicas (PMOs) nanospheres with adjustable shells thickness has been established by a dual-template method without any other extra additions. Triblock copolymer Pluronic P123 and cationic and anionic mixed surfactant (CTAB/SDS) were employed as dual templates and 1,4-Bis(triethoxysilyl) benzene (BTEB) was used as the organicsilica precursor. In the synthesis, single and multiple-shelled hollow nanospheres were synthesized with different CO2 pressures. Moreover, the shell thickness of hollow PMOs nanospheres could be tuned simply by adjusting the CO2 pressure. TEM, SAXS, N2 adsorption-desorption, solid-state NMR, and FTIR were employed to character the structure and component of the prepared PMOs. For their unique multiple-shelled structure, the obtained PMOs nanospheres were used as the drug carrier to demonstrate the high uploading and controlled release of an anti-cancer drug doxorubicin. The versatility of this method was demonstrated with the preparation of hollow PMO nanospheres from other surfactants.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.054
      Issue No: Vol. 247 (2017)
       
  • Preparation of size-controllable monodispersed carbon@silica core-shell
           microspheres and hollow silica microspheres
    • Authors: Minhua Ju; Yupeng Li; Liang Yu; Chongqing Wang; Lixiong Zhang
      Pages: 75 - 85
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Minhua Ju, Yupeng Li, Liang Yu, Chongqing Wang, Lixiong Zhang
      Size-controllable monodispersed carbon@silica core-shell microspheres and hollow silica microspheres were prepared in a simple homemade T-type mixer by polymerization of furfuryl alcohol (FA) and hydrolysis of TEOS in H2SO4 water phase microdroplets to obtain polyfurfuryl alcohol (PFA)@silica microspheres, followed by carbonization and calcination. The FA and TEOS diffuse into the water phase from an oil phase. The flow rates of oil and water phase were 4 and 2 ml h−1, respectively. It was found that the concentration of FA has a more significant effect on the diameter of carbon@silica core-shell microspheres than TEOS due to the template effect of the PFA core. However, the diameter of the hollow silica microspheres was influenced by the concentration of TEOS more significantly. The obtained core-shell microspheres and hollow silica microspheres have large surface area of 555 and 769 m2 g−1, respectively. The hollow silica microspheres have both microporous and mesoporous structure, and the percentage of mesoporous volume was as high as 89%. In addition, based on the study results, a rational formation process of the carbon@silica core-shell microsphere and hollow silica microspheres was assumed.
      Graphical abstract image

      PubDate: 2017-04-04T10:33:12Z
      DOI: 10.1016/j.micromeso.2017.03.058
      Issue No: Vol. 247 (2017)
       
  • Photocatalytic degradation of Rhodamine B over a novel mesoporous
           titanosilicate/g-C3N4 nanocomposite under direct sunlight irradiation
    • Authors: Ajay Kumar Adepu; Rajini Anumula; Venkatathri Narayanan
      Pages: 86 - 94
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Ajay Kumar Adepu, Rajini Anumula, Venkatathri Narayanan
      A novel heterojunction of mesoporous titanosilicate/graphitic carbon nitride (TSCN) inorganic-organic hybrid composite has been developed. The synthesized mesoporous TSCN nanocomposites were characterized by various analytical techniques for structural and chemical properties. Finely distributed porous titanosilicate was observed on the surface of the g-C3N4 from the FE-SEM and TEM analysis. More significantly, the TSCN nanocomposite exhibited enhanced photocatalytic activity in the degradation of Rhodamine B (RhB) under sunlight irradiation. The optimum photocatalytic activity of TSCN10 at 10 wt% of g-C3N4 under visible light is almost 5 and 3 fold higher than pure titanosilicate (TS) and pure g-C3N4 (CN) respectively. The synthesized photo-catalysts are highly stable even after five successive experimental runs. The improved photocatalytic performance of the TSCN10 hybrid nanocomposite photo-catalysts under visible light irradiation was due to the high surface area and synergistic effect. Therefore, TSCN10 hybrid photo-catalyst is a promising material for energy conversion and environmental remediation.
      Graphical abstract image

      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.046
      Issue No: Vol. 247 (2017)
       
  • Pore size effect in the amount of immobilized enzyme for manufacturing
           carbon ceramic biosensor
    • Authors: Elisangela Muncinelli Caldas; Dhjulia Novatzky; Monique Deon; Eliana Weber de Menezes; Plinho Francisco Hertz; Tania Maria Haas Costa; Leliz Ticona Arenas; Edilson Valmir Benvenutti
      Pages: 95 - 102
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Elisangela Muncinelli Caldas, Dhjulia Novatzky, Monique Deon, Eliana Weber de Menezes, Plinho Francisco Hertz, Tania Maria Haas Costa, Leliz Ticona Arenas, Edilson Valmir Benvenutti
      Understanding the mechanism of enzyme immobilization in porous designed matrices is important issue to develop biosensors with high performance. Mesoporous carbon ceramic materials with conductivity and appropriated textural characteristics are promising candidates in this area. In this work, carbon ceramic materials were synthesized using the sol-gel method by planning the experimental conditions to obtain materials with different pore size, from 7 to 21 nm of diameter. The study of the influence of pore size in the biomacromolecules immobilization capacity was performed using glucose oxidase enzyme as probe. The influence of textural characteristics of material in the amount of enzyme immobilized, as well as, its performance as biosensor, was studied. On the surface of highest pore size matrix, it was possible to immobilize the highest amount of enzyme, resulting in better electrochemical response. With this simple material, composed only by silica, graphite and enzyme, which was improved by the amount of immobilized enzyme through the enlargement of matrix pore size, it was possible to prepare an electrode to be applied as biosensor for glucose determination. This electrode presents good reproducibility, sensitivities of 0.33 and 4.44 μA mM−1 cm−2 and detection limits of 0.93 and 0.26 mmol L−1, in argon and oxygen atmosphere, respectively. Additionally, it can be easily reused by simple polishing its surface.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.051
      Issue No: Vol. 247 (2017)
       
  • Nanocrystallite self-assembled hierarchical ZSM-5 zeolite microsphere for
           methanol to aromatics
    • Authors: Yanming Jia; Junwen Wang; Kan Zhang; Wei Feng; Shibin Liu; Chuanmin Ding; Ping Liu
      Pages: 103 - 115
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Yanming Jia, Junwen Wang, Kan Zhang, Wei Feng, Shibin Liu, Chuanmin Ding, Ping Liu
      Nanocrystallite self-assembled hierarchical ZSM-5 zeolite microspheres (NSHZ) were prepared by a simple hydrothermal synthesis procedure in the presence of 3-glycidoxypropyltrimethoxysilane (KH-560). Moreover, the HZSM-5 zeolite (Commercial ZSM-5) and MSHZ zeolite (Mesoporous HZSM-5 synthesized without addition of KH-560) were also introduced as reference samples. The textural and acid properties of all fresh catalysts (HZSM-5, MSHZ, NSHZ) were characterized using XRD, SEM, TEM, ICP, N2 adsorption-desorption, NH3-TPD, Pyridine adsorption IR spectra (Py-IR) and FT-IR techniques. The results showed that uniform NSHZ zeolite microspheres possessed higher crystallinity, smaller crystal size, higher BET surface and pore volume. At the same time, the NSHZ zeolite also had more strong acid sites and proper B/L ratio (The ratio of the amount of Bronsted acid sites to that of Lewis acid sites). Benefiting from these merits, the NSHZ zeolite exhibited higher catalytic lifetime and selectivity of light aromatics (benzene (B), toluene (T) and xylene (X)). The desorption measurements of isooctane showed that NSHZ zeolite had superior diffusion performance, which could effectively promote the fast removal of heavier molecules. In addition, TG analysis of all used catalysts confirmed that NSHZ zeolite had higher coke capability and lower average rate of coke formation.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.035
      Issue No: Vol. 247 (2017)
       
  • Facile synthesis of holey graphene-supported Pt catalysts for direct
           methanol electro-oxidation
    • Authors: Lihui Zhou; Yongxiang Wang; Jing Tang; Jinxia Li; Shaolei Wang; Ying Wang
      Pages: 116 - 123
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Lihui Zhou, Yongxiang Wang, Jing Tang, Jinxia Li, Shaolei Wang, Ying Wang
      A simple synthetic method was developed to produce holey graphene with in-plane nanopores by a fast thermal expansion of graphene oxide (GO) in air and further thermal reduction in N2 flow at 900 °C. The as-synthesized holey graphene nanosheets (HGN) shows meso-macroporous structure and higher surface area than chemically reduced graphene oxide (CRGO) by using hydrazine hydrate. The catalysts of HGN-900 supported Pt nanoparticles (Pt/HGN-900) were further prepared through in-situ chemical co-reduction and applied in the electro-oxidation of methanol. The electrocatalytic performance of catalysts was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) analysis. The results indicate that the catalytic activity of Pt/HGN-10min-900 (377.5 mA mg−1 pt) is bout 1.83 and 2.77 times higher than that of Pt/CRGO-900 (206.1 mA mg−1 pt) and Pt/XC-72 (136.2 mA mg−1 pt) catalysts in 0.5 mol L−1 H2SO4 and 1.0 mol L−1 CH3OH, and Pt/HGN-900 catalysts show higher stable current density compared to that of Pt/XC-72 and Pt/CRGO-900 catalysts.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.061
      Issue No: Vol. 247 (2017)
       
  • Aminosilane-functionalized ZIF-8/PEBA mixed matrix membrane for gas
           separation application
    • Authors: Hamid Reza Amedi; Masoud Aghajani
      Pages: 124 - 135
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Hamid Reza Amedi, Masoud Aghajani
      In this study, bilayer mixed matrix membranes based polyether block amide containing ZIF-8 metal organic nanoparticles, as dispersed particles within the polymer matrix, were synthesized to separate carbon dioxide from methane. To prevent nanocomposite membrane selectivity from a drastic reduction at high loading, the particles were modified by APTMS, APTES. The modified nanoparticles were identified and examined using XRD, BET, DLS, and FTIR. Then the permeability tests were performed with carbon dioxide and methane. A 40 μm thick PES membrane was produced as the base and the PEBA/ZIF-8 MMM with the thickness of about 4 μm as the thin, selectively permeable layer. The APTES-modified ZIF-8 nanoparticles increased forces between the particle surface and polymer chains leading to increased permeability without any significant change in the selectivity. At the loading of 40 wt percentage, the permeability of carbon dioxide significantly improved to 6.7 × 10−8 molm−2s−1pa−1 and selectivity remained about 16.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.04.001
      Issue No: Vol. 247 (2017)
       
  • A theoretical study of confinement effect of zeolite on the ethylene
           dimerization reaction
    • Authors: Wanling Shen
      Pages: 136 - 144
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Wanling Shen
      The influences of pore confinement and topology effect on ethylene dimerization over a series of zeolite, like HMOR, HZSM-5, HBEA and HMCM-22, have been systematically studied by density functional theory including dispersion interaction (DFT-D). Both of the stepwise and the concerted mechanisms are considered. Compared to the corresponding 8T models, the calculated activation energies are considerably reduced in the large models of zeolite due to the pore confinement effect. Moreover, the manners of ethylene dimerization are found to be related to the pore structure of zeolite catalyst. In stepwise mechanism, HMCM-22 shows better activity as suggested by the calculated activation energies. In concerted mechanism, the energy barriers in HBEA and HMCM-22 are much lower than that in HMOR and HZMS-5, indicting a better catalytic performance. By comparing the two mechanisms happened in one zeolite, we suggest that the concerted mechanism is preferable in HBEA, HMCM-22 and HMOR zeolite with large pores, while two mechanisms compete to each other in HZSM-5 with medium-size pores.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.062
      Issue No: Vol. 247 (2017)
       
  • Adsorption of heavy metals on functionalized-mesoporous silica:
           A review
    • Authors: Enshirah Da'na
      Pages: 145 - 157
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Enshirah Da'na
      This work is summarizing the main researcher's contributions in the development of heavy metals adsorbent. Emphasis has been placed on the factors affecting the performance of the adsorbents such as support structural properties, functional groups chemical properties, and properties of the combined inorganic-organic structure. The review includes adsorbents synthesized by two major synthesis routes namely (i) grafting and (ii) co-condensation. This literature review is aiming to trace the main achievements toward the synthesis of an efficient heavy metals adsorbent.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.050
      Issue No: Vol. 247 (2017)
       
  • Single isomerization selectivity of glucose in methanol over Sn-BEC
           zeolite of homogenous Sn distribution
    • Authors: Guanqun Zhang; Pei Feng; Weiping Zhang; Hao Liu; Congxin Wang; Huaijun Ma; Donge Wang; Zhijian Tian
      Pages: 158 - 165
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Guanqun Zhang, Pei Feng, Weiping Zhang, Hao Liu, Congxin Wang, Huaijun Ma, Donge Wang, Zhijian Tian
      Sn-zeolites are important solid Lewis acid catalysts with wide applications to the conversions of various biomass-derived carbohydrates. As the catalytic center, framework Sn of Sn-zeolites can catalyze glucose isomerization to fructose and epimerization to mannose. In practical use, the main obstacle to the application of Sn-zeolites is the lengthy crystallization. In present work, we developed a rapid synthesis route to Sn-zeolites by incorporating Sn into the germanosilicate framework of BEC zeolite via direct hydrothermal procedure. The synthesis time required by Sn-BEC is tenfold shortened than that by the traditional Sn-zeolites like Sn-Beta. The locations of framework Sn atoms of Sn-BEC were investigated by 19F MAS NMR and computational modeling, which indicates that the framework Sn sites of Sn-BEC adopt a uniquely homogenous distribution at the T1 sites. Sn-BEC exhibits high reaction activity and single isomerization selectivity in the glucose conversion in methanol, while Sn-Beta shows both isomerization and epimerization selectivity. The single isomerization selectivity of Sn-BEC suggests the presence of single catalytic center, which is probably caused by the homogenous distribution of framework Sn sites.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.052
      Issue No: Vol. 247 (2017)
       
  • Facile preparation of mesoporous silica monoliths by an inverse micelle
           mechanism
    • Authors: Dario S. Facio; Manuel Luna; Maria J. Mosquera
      Pages: 166 - 176
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Dario S. Facio, Manuel Luna, Maria J. Mosquera
      A well-known drawback of sol–gel materials is their tendency to crack because of the high capillary pressure supported during drying. We have pioneered a facile and low-cost route to obtain monolithic xerogels, from a silica precursor and a surfactant, mixed under ultrasonic agitation. This route presents a clear interest for practical application at industrial scale. In this paper, a model to explain the formation of silica monoliths in the presence of the surfactant is presented. It is demonstrated that a stable microemulsion of water in the silica oligomer media is produced due to the combined effect of surfactant, producing inverse micelles, and ultrasonic agitation. The model proposed, suggests that the water is encapsulated in the surfactant micelles that act as nanoreactors, producing silica primary particles. The growth of these silica seeds continues outside the micelles until the formation of the constituent particles of the xerogel. Next, the particles are packed, and mesopores are produced from the interparticle spaces. This mesoporosity prevents xerogel cracking because it reduces capillary pressure during gel drying. An in-depth investigation of the structure of the xerogels revealed that they are effectively composed of silica nanoparticles of nearly uniform size values that could match with the size of the surfactant inverse micelles. Finally, it was demonstrated that surfactant and water content present a significant effect on the final structure of the xerogels. An increase of surfactant content produces a reduction in particle size, whereas an increase of water produces an opposite effect.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.03.041
      Issue No: Vol. 247 (2017)
       
  • One-step encapsulation of functionalized EAQ and TBAQ molecules inside
           zeolite imidazolate framework-67 and their electrochemical
           characterizations
    • Authors: Ting-Ting Han; Ying-Ying Liu; Guo-Cheng Yang; Jian-Fang Ma
      Pages: 177 - 183
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Ting-Ting Han, Ying-Ying Liu, Guo-Cheng Yang, Jian-Fang Ma
      Three anthraquinone functionalized zeolite imidazolate framework-67 (ZIF-67) hybrids, EAQ@ZIF-67-6 (ZE-6), EAQ@ZIF-67-10 (ZE-10) and TBAQ@ZIF-67-10 (ZT-10) (EAQ = 2-ethylanthraquinone and TBAQ = 2-tert-butylanthraquinone), have been synthesized by one-pot strategy. The successful encapsulation of guests in hybrids has been characterized and confirmed by PXRD, SEM, FT-IR, UV-vis and N2 adsorption. The loading amounts of 11.87 wt% EAQ for ZE-6, 23.11% EAQ for ZE-10, and 23.92% TBAQ for ZT-10 were determined by UV-vis absorption spectroscopy. Their detailed electrochemical studies were performed by using cyclic voltammetry at hybrids modified glassy carbon electrode (GCE) and carbon paste electrode (CPE). The cyclic voltammogram of each hybrid exhibits three pairs of separated redox peaks owing to both electrochemical properties of AQs and ZIF-67. Moreover, the ZE-10 functionalized GCE and CPE have a detection limit of 0.05 mM for H2O2 reduction. These hybrids were the first attempt of electrochemical active molecules embedded into a porous conductive framework.
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      PubDate: 2017-04-11T10:38:09Z
      DOI: 10.1016/j.micromeso.2017.04.005
      Issue No: Vol. 247 (2017)
       
  • Synthesis and characterization of lignosulfonate-derived hierarchical
           porous graphitic carbons for electrochemical performances
    • Authors: Feng Chen; Zeping Zhou; Lingqian Chang; Tairong Kuang; Zhengping Zhao; Ping Fan; Jintao Yang; Mingqiang Zhong
      Pages: 184 - 189
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Feng Chen, Zeping Zhou, Lingqian Chang, Tairong Kuang, Zhengping Zhao, Ping Fan, Jintao Yang, Mingqiang Zhong
      Porous carbon can be widely applied in energy ranging from lithium-ion batteries to supercapacitors. We here propose a novel hierarchical porous graphitic carbon (HPGC) monolith to replace conventional activated carbon for achieving excellent electrochemical performance. In this monolith structure made from the cross-linking of lignosulfonate without any templating agent, the nanoscale core is composed of porous amorphous carbon, while the microscale shell is formed by graphitic carbon and generated within mesoporous wall of HPGC. As evidenced by cyclic voltammetry, the abundant porosity and the high surface area not only offer sufficient reaction sites to store electrical charge physically, but also accelerate the liquid electrolyte to penetrate the electrode and the ions to reach the reacting sites. Of special interest is the fact that HPGC monolith maintains mesoporous without extrinsic template agent.
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      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.010
      Issue No: Vol. 247 (2017)
       
  • Confinement of Mn3+ redox sites in Mn-KIT-6 and its catalytic activity for
           styrene epoxidation
    • Authors: Nilamadanthai Anbazhagan; Gaffar Imran; Ahsanulhaq Qurashi; Arumugam Pandurangan; Shanmugam Manimaran
      Pages: 190 - 197
      Abstract: Publication date: 15 July 2017
      Source:Microporous and Mesoporous Materials, Volume 247
      Author(s): Nilamadanthai Anbazhagan, Gaffar Imran, Ahsanulhaq Qurashi, Arumugam Pandurangan, Shanmugam Manimaran
      In the present study, a series of manganese (Mn) containing 3D cubic mesoporous KIT-6 materials with different Si/Mn ratio (100, 50 25 & 10) having Ia3d space group were synthesized for the first time by a facile one-pot hydrothermal process. The synthesized materials were methodically characterized by various analytical techniques including XRD, N2 sorption, HR-TEM, diffuse reflectance UV–vis (DRS-UV-vis), EPR and FT-IR. The well ordered mesoporous nature of Mn incorporated KIT-6 materials are realized by XRD, N2 adsorption-desorption isotherm and HR-TEM analysis. Surface area, pore volume and pore size of Mn-KIT-6 with different Si/Mn ratio are in the range of 451–786 m2/g, 0.57–0.9 cm3/g and 4.5–4.9 nm respectively. The incorporation of Mn3+ in the framework and fine dispersion of Mn2+ species over silica matrix of Mn-KIT-6 are confirmed by the results of UV-DRS, FT-IR and EPR. Further, the presence of higher amount of Mn2+ extra-framework species in Mn-KIT-6(10) is realized by the presence of high amplitude signal and the contraction in H1 hysteresis loop as shown in EPR and BET isotherm respectively. Catalytic behavior of Mn-KIT-6 material was evaluated for the epoxidation of styrene with various oxidants in which t-butyl hydro peroxide (TBHP) promotes the desired formation of styrene oxide under mild liquid phase conditions. Mn-KIT-6 shown to be highly stable and active which mainly depends on the framework substituted Mn3+ sites.
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      PubDate: 2017-04-18T07:57:50Z
      DOI: 10.1016/j.micromeso.2017.03.049
      Issue No: Vol. 247 (2017)
       
  • Influence of complexing agent on the removal of Pb(II) from aqueous
           solutions by modified mesoporous SiO2
    • Authors: Yu Liu; Zimo Lou; Yue Sun; Xiaoxin Zhou; Shams Ali Baig; Xinhua Xu
      Pages: 1 - 13
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Yu Liu, Zimo Lou, Yue Sun, Xiaoxin Zhou, Shams Ali Baig, Xinhua Xu
      In this study, SiO2-EDTA was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid, trisodium salt (EDTA-silane) and hydroxyl groups for enhanced removal of Pb(II), Pb(II)-Cit (the clathrate generated by Pb(II) and trisodium citrate dehydrate(Cit)) and Pb(II)-EDTA(20%) from aqueous solutions. SiO2-EDTA composites were characterized using SEM, TEM, EDX-mapping, FTIR, XPS and TGA analyses. The influence of solution pH, initial concentration, contact time and co-existing interferents were also studied. Results demonstrated that the composite successfully adsorbed 147.52, 107.65 and 124.18 mg g−1 of Pb(II), Pb(II)-Cit, and Pb(II)-EDTA (20%), respectively with the initial Pb(II) concentration of 100 mg L−1. Kinetics study revealed that the adsorption rate was significantly high at the beginning and then reached to equilibrium within 1.0 h. Moreover, Pb(II) adsorption capacities were found to considerably affected by co-existing cations and not inhibited by natural organic matter (NOM). Characterization analyses confirmed that EDTA was successfully assembled on SiO2 which had been used as a supporting matrix due to its huge specific surface area. Findings from this study suggested that the present composite could be considered as a promising adsorbent for large scale treatment of wastewater containing elevated Pb(II) concentration.
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      PubDate: 2017-03-20T18:34:43Z
      DOI: 10.1016/j.micromeso.2017.03.005
      Issue No: Vol. 246 (2017)
       
  • 2D layered mesoporous MoO2/rGO composites for high performance anode
           materials in lithium-ion battery
    • Authors: Shasha Wang; Baocang Liu; Guolei Zhi; Guangran Xu; Qin Wang; Jun Zhang
      Pages: 14 - 23
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Shasha Wang, Baocang Liu, Guolei Zhi, Guangran Xu, Qin Wang, Jun Zhang
      Transition metal oxides are great promising anode materials with much higher theoretical electrochemical capacities for lithium ion battery compared with the commercialized carbon materials while serious capacity fading and poor cycle stability caused by large volume change and sluggish kinetics must be addressed for their practical application. Herein, we demonstrated a novel strategy to synthesize 2D layered mesoporous-MoO2/graphene (meso-MoO2/rGO) electrode materials using KIT-6/rGO as a template and ammonium molybdate as a precursor via a nanocasting method. By combining graphene with MoO2 and endowing it mesoporous structure, 2D layered meso-MoO2/rGO electrode materials are expected to show superior electrical conductivity, structured flexibility, and chemical stability, which may provide uninhibited conducting pathways for fast charge transfer and transport between oxide nanoparticles and graphene. In addition, mesoporous MoO2 is also anticipated to optimize Li+ transport in pore walls and fast electrolyte transport within highly ordered mesopores. As a result, meso-MoO2/rGO electrode materials possess an ordered mesoporous structure with a superior electrochemical performance. The electrochemical performances were examined using galvanostatical charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) techniques. Benefiting from the combining effects of mesoporous MoO2 and 2D layered graphene, meso-MoO2/rGO electrode materials alleviate the volume effect and give an enhanced discharge and charge capacity and robust cycle stability. The meso-MoO2/rGO composite delivers the first discharge capacity of 1160.6 mA h g−1 and its reversible capacity is 801 mA h g−1 after 50 cycles, making it promising for potential uses as high performance anode materials in lithium-ion battery.
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      PubDate: 2017-03-20T18:34:43Z
      DOI: 10.1016/j.micromeso.2017.03.006
      Issue No: Vol. 246 (2017)
       
  • A new high performance polyamide as an effective additive for modification
           of antifouling properties and morphology of asymmetric PES blend
           ultrafiltration membranes
    • Authors: Abbas Shockravi; Vahid Vatanpour; Zahra Najjar; Saedeh Bahadori; Ali Javadi
      Pages: 24 - 36
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Abbas Shockravi, Vahid Vatanpour, Zahra Najjar, Saedeh Bahadori, Ali Javadi
      Polyethersulfone (PES) ultrafiltration membrane with enhanced simultaneous permeability and fouling–resistance property was prepared using a new synthesized aromatic polyamide (PA-6) as an additive. A series of asymmetric membranes were prepared by adding different amounts of PA-6 to the casting solution using the phase inversion induced by immersion precipitation method. Attenuated total reflection-Fourier transform infrared spectra (ATR-FTIR) and water contact angle measurement confirmed the PA-6 enrichment at the membrane surface and increased the membrane hydrophilicity and wettability. The SEM images elucidated the effect of PA-6 addition on the PES membrane morphology by increasing the pore density. The results of filtration performance, which carried out by dead-end filtration of bovine serum albumin (BSA) solution showed that the permeability and fouling resistance property was improved by optimizing the PA-6 content. When the PA-6 content was 2 wt%, the permeability reached approximately 10 times over the pure PES membrane. In comparison to the blend membrane of PES and 2 wt% of polyvinyl pyrrolidone (PVP), the blend membrane of 2 wt% of PA-6 showed significant flux recovery ability. The rejection of all the blended membranes was approximately at high point over 95%. In addition, the results were compared with those obtained using PVP as a usual additive. Although the PVP blended membranes exhibited higher permeability, they showed lower antifouling properties. Finally, a membrane with 1 wt% PVP and 1 wt% PA-6 was prepared and showed the best performance regarding improved permeability and antifouling properties.
      Graphical abstract image

      PubDate: 2017-03-20T18:34:43Z
      DOI: 10.1016/j.micromeso.2017.03.013
      Issue No: Vol. 246 (2017)
       
  • Flow dynamics of gases inside hydrotalcite-silica micropores
    • Authors: A.D. Wiheeb; T.E. Mohammed; Z.A. Abdel-Rahman; M.R. Othman
      Pages: 37 - 42
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): A.D. Wiheeb, T.E. Mohammed, Z.A. Abdel-Rahman, M.R. Othman
      Maxwell-Stefan diffusion with single-site Langmuir isotherm was used to model the flow of gas inside micro pores of HT-Silica membrane. Coupled with Van't Hoff and Arrhenius equations, the diffusivity and energy contributed by the surface affinity and gas kinetics were quantified and evaluated. Results indicate that all of the four gases being studied were affected by the surface affinity to a significant extent. The surface affinity contributed 62% of the energy in the adsorption of CO2, 48% of the energy in the adsorption of CH4, 48% of the energy in the adsorption of N2 and 46% of the energy in the adsorption of H2. This explains the reason for the higher CO2 permeability despite the fact that the CO2 gas molecules are heavier than the other gas molecules being compared in the analysis.
      Graphical abstract image

      PubDate: 2017-03-20T18:34:43Z
      DOI: 10.1016/j.micromeso.2017.03.021
      Issue No: Vol. 246 (2017)
       
  • Catalytic advantages of NH2-modified MIL-53(Al) materials for Knoevenagel
           condensation reaction
    • Authors: Fernando Martínez; Gisela Orcajo; David Briones; Pedro Leo; Guillermo Calleja
      Pages: 43 - 50
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Fernando Martínez, Gisela Orcajo, David Briones, Pedro Leo, Guillermo Calleja
      The catalytic activity and stability of amino-based MIL-53(Al) materials were tested in Knoevenagel condensation of benzaldehyde with malononitrile reaction. The amine content was modulated by using different ratios of benzene-1,4-dicarboxylic acid (BDC) and 2-amino-benzene-1,4- dicarboxylic acid (NH2-BDC) as organic ligands for the synthesis. The amino-based MIL-53(Al) material synthesized with equimolar amounts of BDC and NH2-BDC (NH2(50%)-MIL-53(Al)) showed the best catalytic performance in terms of benzaldehyde conversion and benzylidenemalononitrile product yield. This equimolar ratio provided the best balance between the amount of amine basic sites and the pore size of the framework. The catalytic activity was also tested for several aldehydes with different molecular sizes and chemical substituents and ethyl cyanoacetate as another methylene compound. The NH2(50%)-MIL-53(Al) material also displayed a remarkable catalytic activity and stability compared to other amino-containing MOF materials (UiO-66-NH2, MIL-101(Al)-NH2 and IRMOF-3) and Na-exchanged beta zeolite. The NH2(50%)-MIL-53(Al) material was considerably active at 40 °C, being its catalytic performance enhanced when using methanol as solvent in the Knoevenagel condensation reaction. The reusability and stability of the NH2(50%)-MIL-53(Al) was shown by a set of five consecutive reaction cycles without appreciable loss of activity and high catalyst recoveries.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.011
      Issue No: Vol. 246 (2017)
       
  • On the catalytic properties and performance of core-shell ZSM-5@MnO
           nanocatalyst used in conversion of methanol to light olefins
    • Authors: Kharazm Khaledi; Mohammad Haghighi; Parisa Sadeghpour
      Pages: 51 - 61
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Kharazm Khaledi, Mohammad Haghighi, Parisa Sadeghpour
      To achieve a proper efficiency in methanol-to-olefin (MTO) process, a series of core-shell ZSM-5@MnO nanocatalysts with different shell thicknesses (6.3–13.7 nm) were successfully synthesized. Approaching bottom-up synthesis through hydrothermal-precipitation method provides well-control condition for core-shell nanoparticles formation. Aging time as an effective synthesis factor controls the rate of precipitation. So, the influence of aging time (5, 10 and 15 h) on the control of the nanometric thickness of shell was investigated. The prepared samples were characterized by XRD, FESEM, TEM, EDX, BET-BJH, FTIR, UV–Vis and NH3-TPD analyses, which in excellent consistency they confirm the formation of core-shell nanoparticles. The result of the both TEM and UV analyses indicate that increasing the aging time led to increase shell thickness. In synthesized core-shell nanocatalyst, ZSM-5@MnO(5) with the minimum shell thickness as well as the maximum core to shell ratio showed the highest olefin productivity enhancement of 15% in comparison with bare ZSM-5. In fact, hybrid ZSM-5@MnO catalyst derived benefits from MnO selectivity toward ethylene as well as high acidic strength of ZSM-5. The exact engineering of core-shell composition changes the shape selectivity of nanocatalyst toward more valuable light olefins (ethylene) and the optimization of the well-controlled shell thickness significantly improves stability and catalytic performance of hybrid catalysts.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.022
      Issue No: Vol. 246 (2017)
       
  • Hierarchically structured carbon/carbon nanocomposites with adjustable
           porosity fabricated by twin polymerization
    • Authors: T. Windberg; T. Ebert; D. Uhlig; S. Schulze; S. Spange
      Pages: 62 - 71
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): T. Windberg, T. Ebert, D. Uhlig, S. Schulze, S. Spange
      Carbon materials with a complex core-shell structure and adjustable porosity are fabricated by subsequent surface polymerization of twin monomers on carbon black and silica particles. The twin monomers 2,2’-spirobi[4H-1,3,2-benzodioxasiline] (Spiro) and tetrafurfuryloxysilane (TFOS) are polymerized in one step to an inorganic/organic hybrid material, which contains nanostructured silica and phenolic resin or poly(furfuryl alcohol), respectively, as organic polymer. After carbonization and the removal of silica, a porous carbon shell with defined porosity is obtained. In this process, Spiro based materials produce microporous carbon and TFOS based materials produce a mesoporous carbon. Quantities of monomer, catalyst and substrate can be varied. This allows to create a library of porous carbon materials with different properties such as controlled porosity, morphology and hierarchically structuring. Thus, mesoporous carbon with a microporous shell can be achieved by using carbon black particles as substrate and Spiro as twin monomer. Furthermore, carbon hollow spheres with a double shell with hierarchically structuring can be synthesized by subsequent polymerization of TFOS and Spiro on silica particles. The porous carbon materials were characterized by quantitative elemental analysis, thermogravimetric measurements, SEM/EDX, TEM, nitrogen sorption isotherms and mercury porosimetry.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.012
      Issue No: Vol. 246 (2017)
       
  • Naturally nitrogen doped porous carbon derived from waste shrimp shells
           for high-performance lithium ion batteries and supercapacitors
    • Authors: Anjon Kumar Mondal; Katja Kretschmer; Yufei Zhao; Hao Liu; Hongbo Fan; Guoxiu Wang
      Pages: 72 - 80
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Anjon Kumar Mondal, Katja Kretschmer, Yufei Zhao, Hao Liu, Hongbo Fan, Guoxiu Wang
      Transformation of biomass wastes into sustainable low cost carbon materials is now a topic of great interest. Here, we describe porous carbon from biomass derived waste shrimp shells and its application in two different energy storage systems. The unique porous structure with the presence of heteroatoms (O, N) makes it promising material for both lithium ion batteries and supercapacitors. When applied as anode materials for lithium ion batteries, the as-prepared carbon showed a specific capacity as high as 1507 mA h g−1 and 1014 mA h g−1 at current densities of 0.1 A g−1 and 0.5 A g−1, respectively, good rate performance and superior cycling stability. The porous carbon-based supercapacitor also delivered a specific capacitance of 239 F g−1 at a current density of 0.5 A g−1 in 6 M KOH electrolyte. The specific capacitance retention is 99.4% even after 5000 charge-discharge cycles, indicating excellent cycling stability. The superior electrochemical performances for both lithium ion batteries and supercapacitors could be ascribed to the high specific surface area, porous structure and nitrogen doping effect.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.019
      Issue No: Vol. 246 (2017)
       
  • Energetic ion induced desorption of hydrogen from porous silicon studied
           by on-line elastic recoil detection analysis
    • Authors: V.S. Vendamani; Saif A. Khan; M. Dhanunjaya; A.P. Pathak; S.V.S. Nageswara Rao
      Pages: 81 - 88
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): V.S. Vendamani, Saif A. Khan, M. Dhanunjaya, A.P. Pathak, S.V.S. Nageswara Rao
      We report a detailed study on the concentration profiles and ion irradiation induced desorption of hydrogen from porous silicon (pSi) by on-line elastic recoil detection analysis (ERDA). 100 MeV Ag ions have been employed to analyze the pSi samples prepared at different etching current densities. The observed blue shift in the photoluminescence of pSi with increase in etching current density is consistent with previous reports. Here we find that the concentration of hydrogen in near surface regions decreases with increase in etching current density. It is also observed that the concentration of hydrogen is greater in the near surface region and decreases rapidly as a function of depth in porous silicon. Further, the ion irradiation induced desorption of hydrogen from pSi has been characterized by the second order decay, indicating that the hydrogen desorbs in molecular form. The rate of desorption is found to be higher from the deeper layers when compared to that of near-surface regions, possibly due to higher diffusivity of elemental hydrogen within the deeper layer. Strong electronic excitations produced by probing beam are expected to be responsible for the observed non-thermal dissociation of SiH bonds and consequent desorption of hydrogen from the surface of pSi in molecular form. These results provide useful information to elucidate 1) the role of hydrogen in determining the optical properties of porous/nano-crystalline silicon and 2) mechanisms that govern the non-thermal dissociation of SiH bonds.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.015
      Issue No: Vol. 246 (2017)
       
  • Incorporation of various heterometal atoms in CHA zeolites by hydrothermal
           conversion of FAU zeolite and their performance for selective catalytic
           reduction of NOx with ammonia
    • Authors: Tomoka Takata; Nao Tsunoji; Yasuyuki Takamitsu; Masahiro Sadakane; Tsuneji Sano
      Pages: 89 - 101
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Tomoka Takata, Nao Tsunoji, Yasuyuki Takamitsu, Masahiro Sadakane, Tsuneji Sano
      Heterometal atom incorporation in CHA aluminosilicate zeolites ([Al, M]-CHA, M = Fe, Ga, Sn) was successfully achieved by hydrothermal conversion of heterometal-incorporated FAU aluminosilicates ([Al, M]-FAU). X-ray powder diffraction (XRD), scanning electron microscopy, diffuse reflectance UV–vis spectroscopy, magic angle spinning NMR, and nitrogen adsorption measurements confirmed the formation of [Al, M]-CHA zeolites with heterometal atoms occupying homogeneously distributed tetrahedral coordination sites. The choice of hydrothermal conversion using [Al, M]-FAU was prompted by the inability to produce [Al, M]-CHA zeolites from amorphous hydrogels. The hydrothermal conversion of [Al, Fe]-FAU to [Al, Fe]-CHA was characterized by XRD, electrospray ionization mass spectrometry, and UV–vis spectroscopy. Analyses of liquid and solid phases during synthesis indicated that metal species present in the solid phase play an important role in the transformation process. We also investigated the effectiveness of Cu-loaded CHA zeolites for the selective catalytic reduction (SCR) of NOx by ammonia (NH3-SCR). Catalytic performance depended strongly on the kind and/or amount of heterometal atom in the [Al, M]-CHA zeolite. Although all fresh catalysts exhibited similar NO conversion efficiencies, there was a difference in NH3 conversion effectiveness at low reaction temperatures. Cu-loaded [Al, Ga]-CHA provided almost 100% NH3 conversion at 150 °C. The [Al, Sn]-CHA catalyst exhibited high stability even after hydrothermal treatment at 900 °C for 4 h. These results confirm hydrothermal conversion as an effective method for synthesizing heterometal-incorporated zeolite catalysts with high NH3-SCR performance.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.018
      Issue No: Vol. 246 (2017)
       
  • In situ preparation and optical properties of metal-8-hydroxyquinoline
           decoration of layered silicate: Self-assembly in the magadiite interface
           by solid-solid reaction
    • Authors: Qiushi Wang; Yifu Zhang; Tao Hu; Xuyang Jing; Changgong Meng
      Pages: 102 - 113
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Qiushi Wang, Yifu Zhang, Tao Hu, Xuyang Jing, Changgong Meng
      We succeeded in the self-assembly of 8-hydroxyquinoline (8Hq)-Li (I), Al (III) and Cu (II) complexes into the interlayer surfaces of layered silicate magadiite (Na2Si14O29·nH2O) and investigated the luminescence of organic metal-chelates in the confined spaces. The measurements, including X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR), thermo-gravimetric analysis and differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), ultraviolet–visible spectroscopy (UV–Vis) and Photoluminescence spectra (PL), confirmed that the metal-organic chelates species were immobilized onto the silicate sheets via ion-dipole interaction and free diffusion. The encapsulation was obtained by a flexible solid-solid reaction, and the present reaction and products have a potential of application to industrial uses. A speculative mechanism is proposed for reaction by the combination of solid-solid and solid-gas intercalation. Furthermore, it was found that the complexes in the interlayer space showed a special fluorescence property than in the crystal state and the confined space of phyllosilicate shows an influence on properties of complexes. Here, a possibility of synthesizing metal-organic complexes that encapsulated in phyllosilicate is given.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.024
      Issue No: Vol. 246 (2017)
       
  • Uptake of vapors of Cd at 480–600 °C and of Zn at 750–880 °C
           by SBA-15
    • Authors: Marek Kosmulski; Edward Mączka
      Pages: 114 - 119
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Marek Kosmulski, Edward Mączka
      Sorption of vapors of Cd at 480–600 °C and of Zn at 750–880 °C by SBA-15 was studied. The amounts of deposited metal ranged from 1 to 11% of the mass of silica, and they were especially high with long deposition times (up to 3 days) at relatively low temperatures. The specific surface areas after metal deposition were lower than those of the original SBA-15 silica, and they decreased with metal contents. The products of deposition of metals on silica can be considered as new materials, metal-modified silicas.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.027
      Issue No: Vol. 246 (2017)
       
  • Triplet-triplet annihilation based upconversion in silica matrices
    • Authors: Giuseppina Massaro; Pier Luigi Gentili; Valeria Ambrogi; Morena Nocchetti; Fabio Marmottini; Fausto Ortica; Loredana Latterini
      Pages: 120 - 129
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Giuseppina Massaro, Pier Luigi Gentili, Valeria Ambrogi, Morena Nocchetti, Fabio Marmottini, Fausto Ortica, Loredana Latterini
      Triplet-triplet annihilation based upconversion emission (TTA-UC), through energy transfer processes among organic dyes, has been achieving great attentions for the potential applications in different fields; an important step forward the application of TTA-UC systems in real devices is the incorporation of the dye couple into solid supports. In this work mesoporous silica (SBA) with regular pores and silica nanoparticles (SNs) with core-shell structure were prepared and loaded with 2,3,7,8,12,13,17,18–octaethyl–21H,23H–porphine platinum(II) (PtOEP) and 1,3,6,8–Tetraphenylpyrene (TPPy) which act as antenna/sensitizer of the TTA-UC process and as light emitting species, respectively. The samples were fully characterized by TEM imaging, XRDP, steady-state and time resolved fluorescence and phosphorescence measurements. No upconverted emission could be detected for the SBA samples because the mesoporous matrix offered a rigid location to the dyes resulting in aggregate and excimer-like species with modified electronic properties. On the other hand, TTA-UC was recorded on SNs samples; in the latter case, steady-state and time resolved phosphorescence and fluorescence measurements indicated that PtOEP was entrapped in monomeric form and TPPy was mainly present as monomer. The careful and detailed photophysical characterization of the obtained nanostructured materials enables the optimization of the conditions to achieve light upconversion in solid matrices.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.008
      Issue No: Vol. 246 (2017)
       
  • Ultrathin mesoporous ZnCo2O4 nanosheets as anode materials for
           high-performance lithium-ion batteries
    • Authors: Mengmeng Zhen; Lu Liu; Cheng Wang
      Pages: 130 - 136
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Mengmeng Zhen, Lu Liu, Cheng Wang
      Transition-metal oxides have been widely explored as the anode materials for lithium-ion batteries (LIBs) because of its low cost and high energy/power density. However, the electrode pulverization and capacity fading during cycling lead to poor cycling performance. Herein, ultrathin ZnCo2O4 nanosheets with desired mesoporosity and high surface area are prepared by a facile hydrothermal approach. Such ZnCo2O4 nanostructures show excellent lithium storage performance as anode materials for LIBs. At a current density of 1 A g−1, the ultrathin ZnCo2O4 nanosheets present an initial specific capacity of 1251 mAh g−1 and the specific capacity remains at ∼810 mAh g−1 even after 200 discharge–charge cycles.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.016
      Issue No: Vol. 246 (2017)
       
  • Aqueous aminosilane solution grafted three dimensional mesoporous silica
           for CO2/N2 separation
    • Authors: Rupak Kishor; Aloke Kumar Ghoshal
      Pages: 137 - 146
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Rupak Kishor, Aloke Kumar Ghoshal
      Three dimensional (3-D) mesoporous silica with large interconnecting pores are found suitable for aminosilane grafting to achieve high CO2 adsorption with higher amine loading. In the present study, cubic KIT-6 is functionalized by (3-aminopropyl)triethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine and N 1 -(3-trimethoxysilylpropyle)diethylene triamine with various concentrations of water in aqueous solvent by post grafting method. The effect of water in grafting of aminosilane onto KIT-6 is analyzed by N2 adsorption/desorption, TEM micrograph, TG analysis and CO2 adsorption. The TG analysis suggests that, surface density of aminosilane increases with increase in water concentration in grafting solvent and TEM micrograph apparently shows the more intense aminosilane on mesoscopic level. The maximum adsorption capacity is 1.60, 2.09 and 2.59 mmol CO2/g-adsorbent for WK.20AP, WK.20DA and WK.10TA, respectively at 30 °C and 1.0 bar. The CO2/N2 selectivity is much higher for aqueous solution grafted adsorbent. Moreover, aqueous solution grafted adsorbents are regenerable showing stable sorption performance till 20 cycles. Thus, aqueous solution grafting is a more efficient way to graft the aminosilane on mesoporous silica as well as design CO2/N2 selective adsorbent.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.023
      Issue No: Vol. 246 (2017)
       
  • Direct synthesis of the aluminosilicate form of the small pore CDO zeolite
           with novel OSDAs and the expanded polymorphs
    • Authors: Raquel Martínez-Franco; Cecilia Paris; Joaquin Martínez-Triguero; Manuel Moliner; Avelino Corma
      Pages: 147 - 157
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Raquel Martínez-Franco, Cecilia Paris, Joaquin Martínez-Triguero, Manuel Moliner, Avelino Corma
      A general procedure to synthesize the Al-containing layered CDO precursor (PreCDO) is presented, allowing its preparation under broad Si/Al molar ratios by using novel pyrrole-derived organic molecules as organic structure directing agents (OSDAs). The direct calcination of the PreCDO materials results in crystalline Al-containing small-pore CDO zeolites with controlled Al species in tetrahedral coordination. In contrast, mild acid treatments on the PreCDO materials allow achieving medium-pore interlayer expanded CDO zeolites (IEZ-CDO). These expanded zeolites show high crystallinity, high porosity and controlled Si/Al molar ratios. Finally, preliminary catalytic results indicate that the Al-containing CDO and IEZ-CDO samples show good activity and selectivity for the selective catalytic reduction (SCR) of NOx, and methanol-to-olefins (MTO) processes, respectively.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.014
      Issue No: Vol. 246 (2017)
       
  • Effect of pore size, aminosilane density and aminosilane molecular length
           on CO2 adsorption performance in aminosilane modified mesoporous silica
    • Authors: Keisuke Hori; Tatsuhiro Higuchi; Yu Aoki; Manabu Miyamoto; Yasunori Oumi; Katsunori Yogo; Shigeyuki Uemiya
      Pages: 158 - 165
      Abstract: Publication date: 1 July 2017
      Source:Microporous and Mesoporous Materials, Volume 246
      Author(s): Keisuke Hori, Tatsuhiro Higuchi, Yu Aoki, Manabu Miyamoto, Yasunori Oumi, Katsunori Yogo, Shigeyuki Uemiya
      Mesoporous silicas with different pore size were modified by aminosilanes with different molecular length. CO2 adsorption capacity was improved by all aminosilane modification, and the CO2 adsorption capacity was further improved with increasing the aminosilane density. However, CO2 adsorption capacity and the amine efficiency of (3-trimethoxysilylpropyl)diethylentriamine (TA) modified mesoporous silicas with small pores such as MCM-41(2.9 or 3.1 nm) and SBA-15(6.2 or 7.1 nm) were significantly decreased at high aminosilane density. In contrast, TA modified SBA-15 with a large pore (10.6 nm) exhibited further improvement of CO2 adsorption capacity and amine efficiency. N2 adsorption desorption measurements suggested that the pore plugging occurred at high aminosilane density in TA modified mesoporous silicas with small pores. In situ FT-IR spectra and the half-value period of CO2 equilibrium adsorption capacity clearly shows the CO2 adsorption kinetics in these adsorbents with small pores were significantly lower than that in the adsorbent with large pores. To develop the CO2 adsorbents with high adsorption performance, the correlation between aminosilane molecular length, pore size of mesoporous silica and aminosilane density should be considered.
      Graphical abstract image

      PubDate: 2017-03-28T10:25:15Z
      DOI: 10.1016/j.micromeso.2017.03.020
      Issue No: Vol. 246 (2017)
       
 
 
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