Degree Name

MS (Master of Science)

Program

Chemistry

Date of Award

5-2016

Committee Chair or Co-Chairs

Aleksey N. Vasiliev

Committee Members

Dane Scott, Gregory W. Bishop

Abstract

Silica gels containing incorporated heteropolyacids (HPAs) were synthesized in acidic media by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using sol-gel technique. Effect of the synthesis conditions on their structure and morphology was studied. Yields of modified materials were some lower as compared to non-modified silica gels. All materials were mesoporous but contained micropores in their structures. Presence of bands of Keggin’s structures in FT-IR spectra along with absence of XRD patterns of crystalline HPAs confirmed their fine incorporation into silica network. Particle sizes of modified materials were 800-1100 nm excepting for W-containing sample obtained with trimethylstearylammonium chloride. This unusual effect was attributed to stabilization of primary silica nanoparticles by interaction between surfactant and HPA. High ratio HPA/TEOS resulted in partial loss of porosity. Obtained results might be used for optimization of synthesis of effective catalysts and adsorbents containing HPAs in mesoporous structure.

Document Type

Thesis - Open Access

Copyright

Copyright by the authors.

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