Deposition of H2-permselective SiO2 films

G. R. Gavalas; C. E. Megiris; S. W. Nam

doi:10.1016/0009-2509(89)85125-5

Deposition of H₂-permselective SiO₂ films

G. R. Gavalas, C. E. Megiris, S. W. Nam

GREEN SCHOOL (Graduate School of Energy and Environment)

Research output: Contribution to journal › Article › peer-review

275 Citations (Scopus)

Abstract

Films of amorphous SiO₂ were deposited within the walls of porous Vycor tubes by SiH₄ oxidation in an opposing-reactants geometry: SiH₄ was passed inside the tube while O₂ was passed outside the tube. The two reactants diffused opposite to each other and reacted within a narrow front inside the tube wall to form a thin SiO₂ film. Once the pores were plugged the reactants could not reach each other and the reaction stopped. At 450°C and 0.1 and 0.33 atm of SiH₄ and O₂, the reaction was complete within 15 min. The thickness of the SiO₂ film was estimated to be about 0.1 μ. Measurements of H₂ and N₂ permeation rates showed that the SiO₂ film was highly selective to H₂ permeation. The H₂: N₂ flux at 450°C varied between 2000 and 3000. Thermal annealing at 600°C reduced somewhat that selectivity. Thermal annealing in the presence of H₂O vapor decreased further the flux of H₂ and increased the flux of H₂. Permeation of H₂ is believed to occur through an activated diffusion mechanism. Applications of such H₂-permeable films to membrance reactors for equilibrium-limited reactions are discussed.

Original language	English
Pages (from-to)	1829-1835
Number of pages	7
Journal	Chemical Engineering Science
Volume	44
Issue number	9
DOIs	https://doi.org/10.1016/0009-2509(89)85125-5
Publication status	Published - 1989

Bibliographical note

Funding Information:
Acknowledgements-This work was supported by NSF grant No. CBT-8806101. The authors acknowledge helpful discussions with Dr Dale Powers of Corning Glass Works.

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering
Industrial and Manufacturing Engineering

Access to Document

10.1016/0009-2509(89)85125-5

Cite this

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title = "Deposition of H2-permselective SiO2 films",

abstract = "Films of amorphous SiO2 were deposited within the walls of porous Vycor tubes by SiH4 oxidation in an opposing-reactants geometry: SiH4 was passed inside the tube while O2 was passed outside the tube. The two reactants diffused opposite to each other and reacted within a narrow front inside the tube wall to form a thin SiO2 film. Once the pores were plugged the reactants could not reach each other and the reaction stopped. At 450°C and 0.1 and 0.33 atm of SiH4 and O2, the reaction was complete within 15 min. The thickness of the SiO2 film was estimated to be about 0.1 μ. Measurements of H2 and N2 permeation rates showed that the SiO2 film was highly selective to H2 permeation. The H2: N2 flux at 450°C varied between 2000 and 3000. Thermal annealing at 600°C reduced somewhat that selectivity. Thermal annealing in the presence of H2O vapor decreased further the flux of H2 and increased the flux of H2. Permeation of H2 is believed to occur through an activated diffusion mechanism. Applications of such H2-permeable films to membrance reactors for equilibrium-limited reactions are discussed.",

author = "Gavalas, {G. R.} and Megiris, {C. E.} and Nam, {S. W.}",

note = "Funding Information: Acknowledgements-This work was supported by NSF grant No. CBT-8806101. The authors acknowledge helpful discussions with Dr Dale Powers of Corning Glass Works.",

year = "1989",

doi = "10.1016/0009-2509(89)85125-5",

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T1 - Deposition of H2-permselective SiO2 films

AU - Gavalas, G. R.

AU - Megiris, C. E.

AU - Nam, S. W.

N1 - Funding Information: Acknowledgements-This work was supported by NSF grant No. CBT-8806101. The authors acknowledge helpful discussions with Dr Dale Powers of Corning Glass Works.

PY - 1989

Y1 - 1989

N2 - Films of amorphous SiO2 were deposited within the walls of porous Vycor tubes by SiH4 oxidation in an opposing-reactants geometry: SiH4 was passed inside the tube while O2 was passed outside the tube. The two reactants diffused opposite to each other and reacted within a narrow front inside the tube wall to form a thin SiO2 film. Once the pores were plugged the reactants could not reach each other and the reaction stopped. At 450°C and 0.1 and 0.33 atm of SiH4 and O2, the reaction was complete within 15 min. The thickness of the SiO2 film was estimated to be about 0.1 μ. Measurements of H2 and N2 permeation rates showed that the SiO2 film was highly selective to H2 permeation. The H2: N2 flux at 450°C varied between 2000 and 3000. Thermal annealing at 600°C reduced somewhat that selectivity. Thermal annealing in the presence of H2O vapor decreased further the flux of H2 and increased the flux of H2. Permeation of H2 is believed to occur through an activated diffusion mechanism. Applications of such H2-permeable films to membrance reactors for equilibrium-limited reactions are discussed.

AB - Films of amorphous SiO2 were deposited within the walls of porous Vycor tubes by SiH4 oxidation in an opposing-reactants geometry: SiH4 was passed inside the tube while O2 was passed outside the tube. The two reactants diffused opposite to each other and reacted within a narrow front inside the tube wall to form a thin SiO2 film. Once the pores were plugged the reactants could not reach each other and the reaction stopped. At 450°C and 0.1 and 0.33 atm of SiH4 and O2, the reaction was complete within 15 min. The thickness of the SiO2 film was estimated to be about 0.1 μ. Measurements of H2 and N2 permeation rates showed that the SiO2 film was highly selective to H2 permeation. The H2: N2 flux at 450°C varied between 2000 and 3000. Thermal annealing at 600°C reduced somewhat that selectivity. Thermal annealing in the presence of H2O vapor decreased further the flux of H2 and increased the flux of H2. Permeation of H2 is believed to occur through an activated diffusion mechanism. Applications of such H2-permeable films to membrance reactors for equilibrium-limited reactions are discussed.

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