Characterization and gas permeation properties of amorphous silica membranes prepared via plasma enhanced chemical vapor deposition

2013 ◽  
Vol 441 ◽  
pp. 45-53 ◽  
Author(s):  
Hiroki Nagasawa ◽  
Hironobu Shigemoto ◽  
Masakoto Kanezashi ◽  
Tomohisa Yoshioka ◽  
Toshinori Tsuru
Keyword(s):  
Chemical Vapor Deposition ◽  
Amorphous Silica ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Gas Permeation ◽  
Silica Membranes ◽  
Permeation Properties

scholarly journals Synthesis of Silica Membranes by Chemical Vapor Deposition Using a Dimethyldimethoxysilane Precursor

Membranes ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 50 ◽  
Author(s):  
S. Ted Oyama ◽  
Haruki Aono ◽  
Atsushi Takagaki ◽  
Takashi Sugawara ◽  
Ryuji Kikuchi
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Composite Membranes ◽  
Hydrothermal Conditions ◽  
Porous Support ◽  
Silica Membranes ◽  
Silica Alumina ◽  
Alumina Composite ◽  
The Stability

Silica-based membranes prepared by chemical vapor deposition of tetraethylorthosilicate (TEOS) on γ-alumina overlayers are known to be effective for hydrogen separation and are attractive for membrane reactor applications for hydrogen-producing reactions. In this study, the synthesis of the membranes was improved by simplifying the deposition of the intermediate γ-alumina layers and by using the precursor, dimethyldimethoxysilane (DMDMOS). In the placement of the γ-alumina layers, earlier work in our laboratory employed four to five dipping-calcining cycles of boehmite sol precursors to produce high H2 selectivities, but this took considerable time. In the present study, only two cycles were needed, even for a macro-porous support, through the use of finer boehmite precursor particle sizes. Using the simplified fabrication process, silica-alumina composite membranes with H2 permeance > 10−7 mol m−2 s−1 Pa−1 and H2/N2 selectivity >100 were successfully synthesized. In addition, the use of the silica precursor, DMDMOS, further improved the H2 permeance without compromising the H2/N2 selectivity. Pure DMDMOS membranes proved to be unstable against hydrothermal conditions, but the addition of aluminum tri-sec-butoxide (ATSB) improved the stability just like for conventional TEOS membranes.

scholarly journals Gas Permeation Property of Silicon Carbide Membranes Synthesized by Counter-Diffusion Chemical Vapor Deposition

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 11
Author(s):  
Takayuki Nagano ◽  
Koji Sato ◽  
Koichi Kawahara
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Active Layer ◽  
Vapor Deposition ◽  
Intermediate Layer ◽  
Chemical Vapor ◽  
Gas Permeation ◽  
Supply Source ◽  
Porous Support ◽  
Counter Diffusion

An amorphous silicon carbide (SiC) membrane was synthesized by counter-diffusion chemical vapor deposition (CDCVD) using silacyclobutane (SCB) at 788 K. The SiC membrane on a Ni-γ-alumina (Al2O3) α-coated Al2O3 porous support possessed a H2 permeance of 1.2 × 10−7 mol·m−2·s−1·Pa−1 and an excellent H2/CO2 selectivity of 2600 at 673 K. The intermittent action of H2 reaction gas supply and vacuum inside porous support was very effective to supply source gas inside mesoporous intermediate layer. A SiC active layer was formed inside the Ni-γ-Al2O3 intermediate layer. The thermal expansion coefficient mismatch between the SiC active layer and Ni-γ-Al2O3-coated α-Al2O3 porous support was eased by the low decomposition temperature of the SiC source and the membrane structure.

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