Preparation and reactive applications of nanoporous silicon carbide membranes

Ciora, Richard; Fayyaz, Babak; Liu, Paul K. T.; Suwanmethanond, Varaporn; Mallada, Reyes; Sahimi, Muhammad; Tsotsis, Theodore T.

doi:10.1016/j.ces.2004.07.015

Cited by 85 publications

(68 citation statements)

References 30 publications

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“…Here, we will consider one such example, silicon carbide, a IV-IV compound, which is a prospective candidate for applications in energy, electronics and medicine. Of particular interest are microporous (Ciora et al 2004) and mesoporous (Yang et al 2006) materials, which exhibit chemical stability and mechanical strength along with relatively narrow pore size distributions. One route to the production of materials with porous architectures is by imitation of naturally occurring minerals with framework structure using differing chemical elements or whole molecular units as building blocks (Yaghi et al 2000;), e.g.…”

Section: Silicon Carbide Clustersmentioning

confidence: 99%

Advances in computational studies of energy materials

Catlow

Guo

Miskufova

et al. 2010

Phil. Trans. R. Soc. A.

128

145

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We review recent developments and applications of computational modelling techniques in the field of materials for energy technologies including hydrogen production and storage, energy storage and conversion, and light absorption and emission. In addition, we present new work on an Sn 2 TiO 4 photocatalyst containing an Sn(II) lone pair, new interatomic potential models for SrTiO 3 and GaN, an exploration of defects in the kesterite/stannite-structured solar cell absorber Cu 2 ZnSnS 4 , and report details of the incorporation of hydrogen into Ag 2 O and Cu 2 O. Special attention is paid to the modelling of nanostructured systems, including ceria (CeO 2 , mixed Ce x O y and Ce 2 O 3 ) and group 13 sesquioxides. We consider applications based on both interatomic potential and electronic structure methodologies; and we illustrate the increasingly quantitative and predictive nature of modelling in this field.

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Section: Silicon Carbide Clustersmentioning

confidence: 99%

Advances in computational studies of energy materials

Catlow

Guo

Miskufova

et al. 2010

Phil. Trans. R. Soc. A.

128

145

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“…33 These membranes have been shown previously to be thermally and hydrothermally stable under conditions akin to the steam-reforming reaction conditions 33 (further details about their preparation and characterization can be found in the original publication). The SiC membranes are highly permselective toward hydrogen, with gases with larger kinetic diameters permeating only by Knudsen diffusion through membrane pinholes and cracks.…”

Section: Mathematical Model Of the Hamr Systemmentioning

confidence: 99%

“…The SiC membranes are highly permselective toward hydrogen, with gases with larger kinetic diameters permeating only by Knudsen diffusion through membrane pinholes and cracks. 33 Mass transfer through the porous membrane is described by the following empirical equation:…”

Section: Mathematical Model Of the Hamr Systemmentioning

confidence: 99%

Hydrogen Production via a High-Efficiency Low-Temperature Reformer

Liu¹,

Tsotsis²

2006

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Media and Process Technology Inc.ii EXECUTIVE SUMMARYFuel cells are promoted by the US government as a viable alternative for clean and efficient energy generation. It is anticipated that the fuel cell market will rise if the key technical barriers can be overcome. One of them is certainly fuel processing and purification. Existing fuel reforming processes are energy intensive, extremely complicated and capital intensive; these disadvantages handicap the scaledown of existing reforming process, targeting distributed or on-board/stationary hydrogen production applications. Our project involves the bench-scale demonstration of a high-efficiency low-temperature steam reforming process. Hydrogen production can be operated at 350 to 400ºC with our invention, as opposed to >800ºC of existing reforming. In addition, our proposed process improves the start-up deficiency of conventional reforming due to its low temperature operation.The objective of this project is to demonstrate the invented process concept via a bench scale unit and verify mathematical simulation for future process optimization study. Under this project, we have performed the experimental work to determine the adsorption isotherm, reaction kinetics, and membrane permeances required to perform the process simulation based upon the mathematical model developed by us. A ceramic membrane coated with palladium thin film fabricated by us was employed in this study. The adsorption isotherm for a selected hydrotalcite adsorbent was determined experimentally. Further, the capacity loss under cyclic adsorption/desorption was confirmed to be negligible. Finally a commercial steam reforming catalyst was used to produce the reaction kinetic parameters required for the proposed operating condition. With these input parameters, a mathematical simulation was performed to predict the performance of the invented process. According to our simulation, our invented hybrid process can deliver 35 to 55% methane conversion, in comparison with the 12 and 18-21% conversion of the packed bed and an adsorptive reactor respectively. In addition CO contamination with <10 to 120 ppm is predicted for the invented process depending upon the cycle time for the PSA type operation. In comparison, the adsorption reactor can also deliver a similar CO contaminant at the low end; however, its high end reaches as high as 300 ppm based upon the simulation of our proposed operating condition. Our experimental results for the packed bed and the membrane reactor deliver 12 and 18% conversion at 400°C, approaching the conversion by the mathematical simulation. Due to the time constraint, the experimental study on the conversion of the invented process has not been complete. However, our inhouse study using a similar process concept for the water gas shift reaction has demonstrated the reliability of our mathematical simulation for the invented process. In summary, we are confident that the invented process can deliver efficiently high purity hydrogen at a low temperature (~400°C).According to our ...

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“…CVI/CVD techniques can be applied at very high temperature and are difficult to control the quality of final products. 11) To overcome these problems, preceramic method has been employed due to low cost, heat-treatment at relatively low temperature and easiness of synthesis. [12][13] Interrante et al 14) measured the He permeability using SiC membrane obtained via the pyrolysis of a partially allyl-substituted hydridopolycarbosilane.…”

Section: Introductionmentioning

confidence: 99%

Gas Permeation of SiC Membrane Coated on Multilayer γ-Al2O3 with a Graded Structure for H2 Separation

Yoon¹,

Kim²,

Kim³

et al. 2010

Korean. J. Mater. Res.

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A promising candidate material for a H 2 permeable membrane is SiC due to its many unique properties. A hydrogen-selective SiC membrane was successfully fabricated on the outer surface of an intermediate multilayer γ-Al 2 O 3 with a graded structure. The γ-Al 2 O 3 multilayer was formed on top of a macroporous α-Al 2 O 3 support by consecutively dipping into a set of successive solutions containing boehmite sols of different particle sizes and then calcining. The boehmite sols were prepared from an aluminum isopropoxide precursor and heated to 80 o C with high speed stirring for 24 hrs to hydrolyze the precursor. Then the solutions were refluxed at 92 o C for 20 hrs to form a boehmite precipitate. The particle size of the boehmite sols was controlled according to various experimental parameters, such as acid types and acid concentrations. The topmost SiC layer was formed on top of the intermediate γ-Al 2 O 3 by pyrolysis of a SiC precursor, polycarbosilane, in an Ar atmosphere. The resulting amorphous SiC-on-Al 2 O 3 composite membrane pyrolyzed at 900 o C possessed a high H 2 permeability of 3.61 × 10 −7 mol·m −2 ·s −1 ·Pa −1 and the H 2 /CO 2 selectivity was much higher than the theoretical value of 4.69 in all permeation temperature ranges. Gas permeabilities through a SiC membrane are affected by Knudsen diffusion and a surface diffusion mechanism, which are based on the molecular weight of gas species and movement of adsorbed gas molecules on the surface of the pores.

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Preparation and reactive applications of nanoporous silicon carbide membranes

Cited by 85 publications

References 30 publications

Advances in computational studies of energy materials

Advances in computational studies of energy materials

Hydrogen Production via a High-Efficiency Low-Temperature Reformer

Gas Permeation of SiC Membrane Coated on Multilayer γ-Al2O3 with a Graded Structure for H2 Separation

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