Synthesis Processes of Nanoporous Solids

2016 ◽  
pp. 297-320
Keyword(s):  
Nanoporous Solids

scholarly journals Modeling Self-Assembly of Silica/Surfactant Mesostructures in the Templated Synthesis of Nanoporous Solids

Langmuir ◽  
2013 ◽  
Vol 29 (7) ◽  
pp. 2387-2396 ◽  
Author(s):  
Germán Pérez-Sánchez ◽  
José R. B. Gomes ◽  
Miguel Jorge
Keyword(s):  
Self Assembly ◽  
Templated Synthesis ◽  
Nanoporous Solids

ChemInform Abstract: Nanoporous Solids: How Do They Form? An in situ Approach

ChemInform ◽  
2014 ◽  
Vol 45 (10) ◽  
pp. no-no
Author(s):  
Gerard Ferey ◽  
Mohamed Haouas ◽  
Thierry Loiseau ◽  
Francis Taulelle
Keyword(s):  
Nanoporous Solids

scholarly journals In situ studies of gas sorption in porous networks

2014 ◽  
Vol 70 (a1) ◽  
pp. C1468-C1468
Author(s):  
Anna Plonka ◽  
Debasis Banerjee ◽  
William Woerner ◽  
John Parise
Keyword(s):  
Relative Humidity ◽  
Porous Materials ◽  
Structural Changes ◽  
Interatomic Potentials ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Enthalpy Of Interaction ◽  
Nanoporous Solids ◽  
Gas Interactions

Selective gas separation is one of the key properties exploited in industrial processes utilizing porous materials. The crystal structure of the native and activated frameworks, along with those of ion exchanged and otherwise modified variants, provide the basis for rational development of gas-selective nanoporous solids. In situ scattering studies of gas-loaded materials provide an understanding of the nature of interactions between sorbed gas and pore surface, which can be vital to development of reliable interatomic potentials, used simulating adsorption behavior. We find that simultaneous observation of the Differential Scanning Calorimetry coupled with x-ray diffraction (DSC-XRD) measurements is a particularly powerful tool 1, 2. The powder diffraction pattern can be monitored for changes, such as framework collapse, as porous materials are heated and activated. Apart from monitoring structural changes, thermal responses accompanying dynamic exposure to gases at variable humidity, and as the temperature is varied, provides a reliable tool in order to screen for new and potentially selective porous materials. The DSC signal provides a reliable means to determine the enthalpy of interaction between framework and gas, and there is experimental evidence this signal may distinguish between gas interactions with bare metal sites in the activated framework and other gas-framework interactions. Studies where the enthalpy of interaction and X-ray scattering from low angle peaks, which are most sensitive to the filling and evacuation of pores of the porous materials are monitored, can be coupled with varying the nature of the gas and the relative humidity. These studies are conveniently carried out with a modified gas manifold interfaced to a slightly modified Rigaku corporation DSC-XRD, which allows studies from about 150 – 600 K. Illustrative examples of the use of this laboratory based equipment, which provide the underpinnings of detailed single crystal studies of gas-loaded materials, include studies of porous calcium based coordination network (CaSDB, SDB: 4,4' - sulfonyldibenzoate), which is selective for CO2, even in the presence of high relative humidity (RH). Recent results from a series of materials studied in the home laboratory and at synchrotron sources will be presented.

scholarly journals Properties of adsorbed hydrogen and methane films on nanoporous solids

2017 ◽  
Author(s):  
◽  
Andrew Karl Gillespie
Keyword(s):  
Energy Density ◽  
Fossil Fuels ◽  
Storage Capacity ◽  
Isosteric Heat ◽  
Adsorptive Capacity ◽  
Storage Tanks ◽  
Adsorbed Film ◽  
Renewable Fuel ◽  
Storage Methods ◽  
Nanoporous Solids

The environmental impacts and costs of fossil fuels necessitate the development of clean, renewable fuel sources for vehicular applications. Hydrogen based systems, with water as their byproduct, have zero carbon emissions, which mitigates the negative effects of using conventional fossil fuels. Further, hydrogen can be produced from renewable energy sources, such as renewable electrolysis and biohydrogen. When produced from such methods, hydrogen is a renewable fuel. The main drawback of hydrogen as a fuel is its low energy density at ambient pressures and temperatures. Hydrogen has a mass energy density three times that of gasoline, but occupies more than 30 times the volume. Therefore, it is necessary to increase the volumetric energy density of hydrogen before it can be considered as a practical option. Conventional storage methods for hydrogen include compression and liquefaction. In order to yield a sufficient deliverable storage capacity, these methods require high pressures or cryogenic temperatures. Compressed gas systems require tanks with massive walls which reduce spatial and mass efficiency and thus, vehicle performance. These systems are geometrically constrained due to their high pressure, making them difficult to integrate into the vehicle. Due to these constraints, conventional storage methods are insufficient at increasing the energy density of hydrogen to compete with that of fossil fuels. To bridge this gap, it is necessary to develop a low-pressure, high-capacity storage technology in order to address the temperature, pressure, weight, and volume constraints present in the conventional storage methods. To achieve this, we investigate the storage capacity of nanoporous solids, which are capable of densifying a high volume of hydrogen on their surfaces through the process of adsorption. Several factors affect the adsorptive capacity of these materials, such as specific surface area, pore geometry, and the strength of the adsorption potential. The strength of the adsorption potential often cited as a figure of merit for the adsorptive capacity of new materials and is commonly estimated through the Clausius-Clapeyron relation between two adsorption isotherms. However, this method requires an assumption of the adsorbed film volume, which poses as the primary source of error. From supercritical hydrogen isotherms from 77 - 473 Kelvin, we propose a method to measure the volumes, densities, and thicknesses of the adsorbed film. This method will lead to more accurate isosteric heat calculations, which is an important factor to consider when designing storage tanks. Furthermore, we investigated the correlation between the isosteric heat of adsorption, surface chemistry, and pore size distribution with an adsorbed film. In most of the samples the saturated film density was approximately 100 g/L across a large range of temperatures. The specific volumes of the adsorbed film scaled with specific surface area and binding energies. The saturated, adsorbed film density approaches 100 g/L for all adsorbent types at 77 K. The saturated, adsorbed film thickness was between 3.1 - 3.2 [superscript A] for hydrogen on most sorbent materials. In the future, we intend to investigate changes in these parameters of the adsorbed film with increasing temperature as well as the affects that these changes may have on the estimated values of isosteric heat. Improved estimates of isosteric heats of adsorption will assist in optimizing the thermal properties of on-board storage tanks.

scholarly journals Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

Nanoscale ◽  
2019 ◽  
Vol 11 (48) ◽  
pp. 23304-23317 ◽  
Author(s):  
Kathrin Sentker ◽  
Arda Yildirim ◽  
Milena Lippmann ◽  
Arne W. Zantop ◽  
Florian Bertram ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Liquid Crystals ◽  
Computer Simulations ◽  
Self Assembly ◽  
X Ray ◽  
X Ray Scattering ◽  
Nanoporous Solids ◽  
Ray Scattering

X-ray scattering and optical polarimetry evidence in agreement with Monte Carlo computer simulations that confinement-controlled self-assembly of liquid crystals in nanopores allows for designing photonic metamaterials with adaptive birefringence.

scholarly journals Thin Films of Homochiral Metal–Organic Frameworks for Chiroptical Spectroscopy and Enantiomer Separation

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 686 ◽  
Author(s):  
Chun Li ◽  
Lars Heinke
Keyword(s):  
Thin Films ◽  
Enantiomer Separation ◽  
Metal Organic Frameworks ◽  
Chiral Molecules ◽  
The Status ◽  
Metal Organic ◽  
Promising Application ◽  
Nanoporous Solids ◽  
Chiroptical Spectroscopy

Chiral nanoporous solids are a fascinating class of materials, allowing efficient enantiomer separation. Here, we review the status, applications, and potential of thin films of homochiral metal–organic frameworks (MOFs). Combining the advantages of MOFs, whose well-defined, crystalline structures can be rationally tuned, with the benefits of thin films enables new opportunities for the characterization of the enantioselectivity, e.g., via chiroptical spectroscopy and straightforward molecular uptake quantifications. By incorporating photoresponsive molecules in the chiral MOF films, the enantioselectivity of the material can be dynamically remote-controlled. The most promising application of MOF films is their use as membranes, where the enantioselective separation of chiral molecules is demonstrated and parameters for further improvements are discussed.

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