The Effect of Pyrolysis Temperature and Formulation on Pore Size Distribution and Surfacearea of Carbon Aerogels

1992 ◽  
Vol 270 ◽  
Author(s):  
S.S. Hulsey ◽  
C.T. Alviso ◽  
F.M. Kong ◽  
R.W. Pekala
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Pyrolysis Temperature ◽  
Bet Surface Area ◽  
Vitreous Carbon ◽  
Basic Medium ◽  
Carbon Aerogels ◽  
Size Distributions ◽  
Structure Property ◽  
Pore Size Distributions

ABSTRACTRecently we reported the chemistry-structure-property relationships of organic aerogels, which are synthesized by the polycondensation of resorcinol and formaldehyde in a slightly basic medium, followed by supercritical drying. These materials can be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. As measured by gas adsorption techniques, the BET surface area and pore size distributions of micro and meso pores of the carbon aerogels are affected both by the pyrolysis temperature and the formulation. Definite trends are observed in our preliminary measurements; for example, the surface area decreases with increasing pyrolysis temperature until a plateau is reached at about 900°C. This paper explores the effects of pyrolysis temperature and aerogel density on the BET surface area and pore size distributions.

scholarly journals Comparison of Nitrogen Adsorption and Mercury Penetration Results. Pore Size Distributions for a Series of Mo-A12O3 Catalysis with Increasing MoO3 Content

1987 ◽  
Vol 4 (1-2) ◽  
pp. 87-104 ◽  
Author(s):  
Bruce D Adkins ◽  
Jill B. Heink ◽  
Burtron H. Davis
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Three Dimensional ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Size Distributions ◽  
Electron Microscopic ◽  
Pore Size Distributions ◽  
Electron Microscopic Data ◽  
Penetration Data

Scanning electron microscopic data, X-ray diffraction patterns and porosity measurements are consistent with a structure for an Mo-A12O3 catalyst series containing a single surface layer of Mo up to the point where the Mo loadings exceed the amount required for a monolayer. For greater Mo loadings than required for a monolayer, three dimensional orthorhombic MoO3 is also present. The cumulative pore volume, on an alumina basis, does not appear to be significantly altered by MoO3 loadings up to about 15 wt.%. The BET surface area, on an alumina basis, remains constant with Mo loading. However, the apparent surface area calculated from mercury penetration data decreases with Mo loading. For these materials with cylindrical pores, the Broekhoff-deBoer model for the calculation of pore size distributions produced closer agreement to the mercury penetration pore size distribution. This is in contrast to materials composed of nonporous spheres where the Broekhoff-deBoer model provided poorer agreement to mercury penetration results than either the Cohan or a packed sphere model. The results show that, within a factor of two the pore size distributions calculated from nitrogen adsorption and mercury penetration data are comparable.

Ni and Cu Incorporated Mesoporous Nanocomposite Catalytic Materials

2008 ◽  
Vol 8 (2) ◽  
pp. 549-556 ◽  
Author(s):  
Asli Nalbant ◽  
Timur Dogu ◽  
Suna Balci
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Atomic Ratio ◽  
Nanocomposite Materials ◽  
Size Distributions ◽  
Hydrothermal Route ◽  
Average Pore ◽  
Pore Size Distributions ◽  
Xrd Patterns ◽  
Mcm 41

Nickel and copper incorporated MCM-41-like mesoporous nanocomposite materials prepared by the direct hydrothermal synthesis and the impregnation procedures showed highly attractive pore structure and surface area results for catalytic applications. The XRD patterns showed that characteristic MCM-41 structure was preserved for the materials synthesized following an impregnation procedure before the calcination step. The surface area of the Cu impregnated material with a quite high Cu/Si atomic ratio (0.19) was 631 m2/g. Very narrow pore size distributions with an average pore diameter of about 2.7 nm were obtained as a result of plugging of some of the smaller pores by Cu nanoballs. For lower metal to Si ratios (for instance for Ni/Si = 0.06) much higher surface area values (1130 m2/g) were obtained. In the case of nanocomposite materials synthesized by the direct hydrothermal route, MCM-41 structure was not destroyed for samples containing metal to Si atomic ratios as high as 0.12. In the case of materials containing Cu/Si and Ni/Si ratios over 0.2 wider pore size distributions and some decrease of surface area were observed.

scholarly journals Computational design of biopolymer aerogels and predictive modelling of their nanostructure and mechanical behaviour

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rajesh Chandrasekaran ◽  
Markus Hillgärtner ◽  
Kathirvel Ganesan ◽  
Barbara Milow ◽  
Mikhail Itskov ◽  
...  
Keyword(s):  
Pore Size ◽  
Voronoi Tessellation ◽  
Strain Curve ◽  
Predictive Modelling ◽  
Computational Design ◽  
Nanoporous Materials ◽  
Synthesis Process ◽  
Size Distributions ◽  
Structure Property ◽  
Pore Size Distributions

AbstractTo address the challenge of reconstructing or designing the three-dimensional microstructure of nanoporous materials, we develop a computational approach by combining the random closed packing of polydisperse spheres together with the Laguerre–Voronoi tessellation. Open-porous cellular network structures that adhere to the real pore-size distributions of the nanoporous materials are generated. As an example, κ-carrageenan aerogels are considered. The mechanical structure–property relationships are further explored by means of finite elements. Here we show that one can predict the macroscopic stress–strain curve of the bulk porous material if only the pore-size distributions, solid fractions, and Young’s modulus of the pore-wall fibres are known a priori. The objective of such reconstruction and predictive modelling is to reverse engineer the parameters of their synthesis process for tailored applications. Structural and mechanical property predictions of the proposed modelling approach are shown to be in good agreement with the available experimental data. The presented approach is free of parameter-fitting and is capable of generating dispersed Voronoi structures.

CHARACTERIZATION OF PORE SIZE DISTRIBUTIONS USING NON-NEWTONIAN FLUIDS

2020 ◽  
Author(s):  
Scott C. Hauswirth ◽  
◽  
Majdi Abou Najm ◽  
Christelle Basset
Keyword(s):  
Pore Size ◽  
Newtonian Fluids ◽  
Size Distributions ◽  
Pore Size Distributions

Preparation of P(GMA-co-EGDMA) Monolithic Columns with Adjustable Porous Properties

2014 ◽  
Vol 936 ◽  
pp. 942-949 ◽  
Author(s):  
Hao Tian Zhang ◽  
Qiu Yu Zhang ◽  
Bao Liang Zhang ◽  
Chun Mei Li
Keyword(s):  
Pore Size ◽  
Monolithic Column ◽  
Organic Polymer ◽  
Monolithic Columns ◽  
Size Distributions ◽  
Notable Effect ◽  
Pore Size Distributions ◽  
Porous Properties ◽  
Glass Tubes ◽  
First Time

Porous properties have notable effect on separating effect of organic polymer-based monolithic column. Different applications of monolithic columns require tailored pore size distributions. On account of that, P(GMA-co-EGDMA) monolithic columns were prepared with novel ternary porogenic agents. Glass tubes was chosen as polymerization mold. Moreover, factors influencing the inner pore morphology, pore size and specific surface area were investigated systematically. The results showed that the increasing of the solubility of porogenic agents and the amount of crosslinker, the decreasing of the amount of porogenic agents and temperature rising all could give rise to the decreasing of pore size. Remarkably, the effect of initiator was studied for the first time. The results showed that amount of initiator had no remarkable influence on porous properties. By controlling effect factors, P(GMA-co-EGDMA) Monolithic Columns with pore size from dozens to thousands of nanometer, which can be applied in separation of molecules with different size.

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