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Nicola Husing - One of the best experts on this subject based on the ideXlab platform.
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in situ small angle neutron scattering investigation of adsorption induced deformation in silica with Hierarchical Porosity
Langmuir, 2019Co-Authors: Lukas Ludescher, Roland Morak, Christian Balzer, Anna Waag, Stephan Braxmeier, Florian Putz, Sebastian Busch, Gennady Y Gor, Alexander V Neimark, Nicola HusingAbstract:Adsorption-induced deformation of a series of silica samples with Hierarchical Porosity has been studied by in situ small-angle neutron scattering (SANS) and in situ dilatometry. Monolithic samples consisted of a disordered macroporous network of struts formed by a 2D lattice of hexagonally ordered cylindrical mesopores and disordered micropores within the mesopore walls. Strain isotherms were obtained at the mesopore level by analyzing the shift of the Bragg reflections from the ordered mesopore lattice in SANS data. Thus, SANS essentially measured the radial strain of the cylindrical mesopores including the volume changes of the mesopore walls due to micropore deformation. A H2O/D2O adsorbate with net zero coherent neutron scattering length density was employed in order to avoid apparent strain effects due to intensity changes during pore filling. In contrast to SANS, the strain isotherms obtained from in situ dilatometry result from a combination of axial and radial mesopore deformation together with micropore deformation. Strain data were quantitatively analyzed with a theoretical model for micro-/mesopore deformation by combining information from nitrogen and water adsorption isotherms to estimate the water-silica interaction. It was shown that in situ SANS provides complementary information to dilatometry and allows for a quantitative estimate of the elastic properties of the mesopore walls from water adsorption.
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sol gel synthesis of monolithic materials with Hierarchical Porosity
Chemical Society Reviews, 2016Co-Authors: Andrea Feinle, Michael S Elsaesser, Nicola HusingAbstract:The development of synthetic routes to Hierarchically organized porous materials containing multiple, discrete sets of pores having disparate length scales is of high interest for a wide range of applications. One possible route towards the formation of multilevel porous architectures relies on the processing of condensable, network forming precursors (sol–gel processes) in the presence of molecular porogens, lyotropic mesophases, supramolecular architectures, emulsions, organic polymers, or ice. In this review the focus is on sol–gel processing of inorganic and organic precursors with concurrently occurring microscopic and/or macroscopic phase separation for the formation of self-supporting monoliths. The potential and the limitations of the solution-based approaches is presented with special emphasis to recent examples of Hierarchically organized silica, metal oxides and phosphates as well as carbon monoliths.
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chemical phase separation strategies towards silica monoliths with Hierarchical Porosity
Chemical Society Reviews, 2013Co-Authors: Christos Triantafillidis, Michael S Elsaesser, Nicola HusingAbstract:In this tutorial review the preparation of monolithic silica materials with Hierarchical Porosity by the competing processes of sol–gel transition and chemical phase separation is summarized. Four principally different routes will be discussed in detail, including multiple micellar as well as high internal phase emulsion templating routes. Special emphasis is given to polymer-induced phase separation strategies either based on the deliberate choice of the polymer that is mixed into the gelling system or by the application of specifically designed hydrophilic silane precursors.
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glycol modified silanes in the synthesis of mesoscopically organized silica monoliths with Hierarchical Porosity
Chemistry of Materials, 2005Co-Authors: Doris Brandhuber, Viktoria Torma, Christina Raab, Herwig Peterlik, And Alexander Kulak, Nicola HusingAbstract:Silica monoliths exhibiting a unique Hierarchical network structure with a bimodal pore size distribution and high surface areas were prepared from three different glycol-modified silanes by sol−gel processing. Tetrakis(2-hydroxyethyl)-, tetrakis(2-hydroxypropyl)-, and tetrakis(2,3-dihydroxypropyl)orthosilicate were obtained by transesterification reaction from tetraethylorthosilicate and the corresponding alcohols. The present work shows that, for ethylene glycol- and propane-1,2-diol-modified silanes, simply the release of the corresponding diols during sol−gel processing in the presence of block copolymeric surfactants such as Pluronic P123 results in phase separation on different levels. In addition to an extraordinary cellular network structure with interconnected macropores of several hundreds of nanometers in diameter, the material exhibits a well-ordered mesostructure with periodically arranged mesopores of about 6−7 nm in diameter. Interestingly, the application of glycerol-modified silanes at th...
Markus Antonietti - One of the best experts on this subject based on the ideXlab platform.
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efficiency of ni nanoparticles supported on Hierarchical porous nitrogen doped carbon for hydrogenolysis of kraft lignin in flow and batch systems
ACS Sustainable Chemistry & Engineering, 2017Co-Authors: Sandy M G Lama, Jonas Pampel, Timpatrick Fellinger, Vladimir Beskoski, Latinka Slavkovicbeskoski, Markus Antonietti, Valerio MolinariAbstract:Ni nanoparticles supported on nitrogen-doped carbon (NDC) prepared via salt-melt synthesis with a Hierarchical Porosity were successfully applied as the catalyst for the degradation of Kraft lignin. It is shown that Ni-NDC is more efficient when compared to Ni nanoparticles deposited on an N-free carbon support, prepared with similar Porosity features (Ni–C) and to Ni nanoparticles deposited on a commercial carbon (Ni-Cref). The efficiency of these materials was compared for reactions performed both in batch and flow reactors, highlighting the effect of the reactor setup on the stability of the recovered catalysts.
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synthesis of high surface area tin carbon composite materials with Hierarchical Porosity via reactive templating
Chemistry of Materials, 2008Co-Authors: Anna Fischer, Youngsi Jun, Arne Thomas, Markus AntoniettiAbstract:In this work, the synthesis of porous TiN/carbon composites via “reactive hard templating” is presented. The concept of this synthesis strategy is to use the template, responsible for the final morphology of the TiN/carbon material, as a reactant and nitrogen source; template removal is unnecessary as the final product is obtained as such. As reactive templates, two types of macroporous graphitic carbon nitride powders with different pore sizes (60 nm or 500 nm spherical pores) were used. The powders were infiltrated with a titanium precursor solution, aged for 1 night at 100 °C under air, and subsequently annealed at 800 °C to create the final nanocrystalline porous TiN/carbon structures. The final products were analyzed by XRD, TEM, HRTEM, EA, and gas sorption experiments. It was shown that the morphology of the resulting material generates from a nanocoating of the macropores of the carbon nitride reactive template, yielding aggregated hollow TiN/C spheres with Hierarchical Porosity.
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synthesis and characterization of sic materials with Hierarchical Porosity obtained by replication techniques
Physical Chemistry Chemical Physics, 2006Co-Authors: Kirstin Sonnenburg, Philipp Adelhelm, Markus Antonietti, Bernd M Smarsly, Robert Noske, Peter StrauchAbstract:Porous silicon carbide monoliths were obtained using the infiltration of preformed SiO2 frameworks with appropriate carbon precursors such as mesophase pitch. The initial SiO2 monoliths possessed a Hierarchical pore system, composed of an interpenetrating bicontinuous macropore structure and 13 nm mesopores confined in the macropore walls. After carbonization, further heat treatment at ca. 1400 °C resulted in the formation of a SiC–SiO2 composite, which was converted into a porous SiC monolith by post-treatment with ammonium fluoride solution. The resulting porous SiC featured high crystallinity, high chemical purity and showed a surface area of 280 m2 g−1 and a pore volume of 0.8 ml g−1.
Jim Yang Lee - One of the best experts on this subject based on the ideXlab platform.
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fe doped mnxoy with Hierarchical Porosity as a high performance lithium ion battery anode
Advanced Materials, 2013Co-Authors: Chunliu Fang, Bo Ding, Jim Yang LeeAbstract:Fe-doped Mnx Oy with Hierarchical Porosity is prepared from a nanocasting technique using amine-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) (BPPO) membranes as the sacrificial template. The synergistic coupling of a percolating macroporous network, uniformly distributed mesopores, and optimal iron doping is used to improve the electronic and ionic wirings of manganese oxides for Li(+) storage via the conversion reaction. Very impressive Li(+) storage capabilities are shown.
Feng Wang - One of the best experts on this subject based on the ideXlab platform.
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a facile route to bimetal and nitrogen codoped 3d porous graphitic carbon networks for efficient oxygen reduction
Small, 2016Co-Authors: Zhengping Zhang, Feng WangAbstract:: Bimetal nitrogen-doped carbon with both Fe and Co, derived from the pyrolysis carbon of iron and cobalt phthalocyanine-based conjugated polymer networks, possesses a few-layer graphene-like texture with Hierarchical Porosity in meso/micro multimodal pore size distribution. The novel electrocatalyst exhibits Pt-like catalytic activity and much higher catalytic durability for oxygen reduction.
Mario Caccia - One of the best experts on this subject based on the ideXlab platform.
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synthesis of high surface area mesoporous sic with Hierarchical Porosity for use as catalyst support
Journal of the American Ceramic Society, 2020Co-Authors: Adrian Ortegatrigueros, Javier Narciso, Mario CacciaAbstract:Financial support from the Generalitat Valenciana under the PhD grant Vali + d and the “Ministerio de Economia y Competitividad” (Grant MAT2017-86992-R), and action Mobility of Alicante University is gratefully acknowledged.