Structural analysis of the microporous semiconductor K-SBC-1 during its reversible sorption of water

Journal Article · Sat Aug 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.05.028· OSTI ID:21370529

Shulman, Alexander ^[1]; Langer, Vratislav ^[2]

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1. Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, 412 96 Goeteborg (Sweden)
2. Department of Chemical and Biological Engineering, Environmental Inorganic Chemistry, Chalmers University of Technology, 412 96 Goeteborg (Sweden)

The reversible sorption of water molecules in the crystalline microporous semiconductor K-SBC-1 was investigated using temperature-resolved single-crystal XRD analysis. Three crystallographic sites of adsorbed water molecules, differing in adsorption strength, were discovered in the pores of K-SBC-1. The least tightly bound is located at the centre of the {l_brace}Sb{sub 12}O{sub 18}{r_brace} tube and begins to desorb around 50 deg. C. Above 200 deg. C the more strongly bound water molecules rearrange from their potassium-coordinating positions to the centre of the tube, thus obtaining the characteristics of the loosely bound water, and desorb thereafter. At 240 deg. C approximately 10% of the water has desorbed, leaving the host framework of K-SBC-1 intact. Upon re-adsorption of water at room temperature the molecules preferentially adsorb at sites in the centre of the {l_brace}Sb{sub 12}O{sub 18}{r_brace} tube. This shows that a heat treatment of 240-300 deg. C activates K-SBC-1 for sorption and explains the observed facile desorption of water from activated samples. - Graphical abstract: Three crystallographic adsorption sites for water are found in the crystalline microporous semiconductor K-SBC-1. Upon heating to 240 deg. C the material desorbs enough strongly bound water to become activated for reversible sorption at room temperature, due to redistribution of water occupancy between the strong and weak adsorption sites.

• OSTI ID: 21370529
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 8 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ADSORPTION
ALKALI METAL COMPOUNDS
ANTIMONY COMPOUNDS
ANTIMONY OXIDES
CHALCOGENIDES
COHERENT SCATTERING
CRYSTALLOGRAPHY
CRYSTALS
DESORPTION
DIFFRACTION
HEAT TREATMENTS
HEATING
HYDROGEN COMPOUNDS
MATERIALS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
SCATTERING
SEMICONDUCTOR MATERIALS
SORPTION
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
WATER
X-RAY DIFFRACTION