Synthesis of hydrogen permselective SiO sub 2 , TiO sub 2 , Al sub 2 O sub 3 , and B sub 2 O sub 3 membranes from the chloride precursors

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00057a015· OSTI ID:5875049

Tsapatsis, M; Kim, S; Nam, S W; Gavalas, G ^[1]

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1. California Inst. of Tech., Pasadena, CA (United States). Div. of Chemistry and Chemical Engineering

Hydrogen-permselective membranes were synthesized by chemical vapor deposition of SiO{sub 2}, TiO{sub 2}, Al{sub 2}O{sub 3}, and B{sub 2}O{sub 3} layers within the pores of Vycor tubes. The deposition involved reaction of SiCl{sub 4}, etc., with water at 100-800{degrees} C depending on the chloride and the reaction geometry. Permselective SiO{sub 2} layers could be formed in either the one-sided or the two-sided (opposing reactants) geometry, while deposition of TiO{sub 2} and Al{sub 2}O{sub 3} layers was achieved only in the two-sided geometry. The permeation coefficients at 450{degrees} C were 0.3 and 0.1 cm{sup 3}/(cm{sup 2} {center dot} min {center dot} atm) for SiO{sub 2} membranes produced in the one-sided and two-sided geometries, respectively. The H{sub 2}/N{sub 2} permeation ratios were 1000-5000. The TiO{sub 2} and Al{sub 2}O{sub 3} membranes had somewhat lower permeation coefficients and H{sub 2}/N{sub 2} ratios. The membranes were characterized by scanning electron microscopy (SEM) and electron microprobe analysis (EMA). In this paper a reaction mechanism is suggested involving heterogeneous reactions of chloride and water molecules with hydroxyl and chloride groups in the growing deposit layer.

• OSTI ID: 5875049
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Vol. 30:9; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
SYNTHESIS
BORON OXIDES
HYDROGEN
MEMBRANES
SILICA
SILICON CHLORIDES
CHEMICAL REACTIONS
TITANIUM OXIDES
WATER
CHEMICAL VAPOR DEPOSITION
HYDROXYL RADICALS
PERMEABILITY
POROSITY
PRECURSOR
SCANNING ELECTRON MICROSCOPY
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TUBES
VYCOR
ALUMINIUM COMPOUNDS
BORON COMPOUNDS
CHALCOGENIDES
CHEMICAL COATING
CHLORIDES
CHLORINE COMPOUNDS
DEPOSITION
ELECTRON MICROSCOPY
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
MICROSCOPY
MINERALS
NONMETALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RADICALS
SILICON COMPOUNDS
SILICON HALIDES
SILICON OXIDES
SURFACE COATING
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
400201 - Chemical & Physicochemical Properties
400800 - Combustion
Pyrolysis
& High-Temperature Chemistry