Study of Phosphate-Modified TiO2 (Anatase) Full article
Journal |
Journal of Catalysis
ISSN: 0021-9517 , E-ISSN: 1090-2694 |
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Output data | Year: 1989, Volume: 116, Number: 2, Pages: 498-505 Pages count : 8 DOI: 10.1016/0021-9517(89)90116-4 | ||||
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Abstract:
Pure and phosphate-modified titanium dioxide (anatase) have been studied by IR spectroscopy of probe molecules, X-ray photoelectron spectroscopy, X-ray phase analysis, electron microscopy, etc. It is established that the phosphate anions are strongly bonded to the anatase surface and are stable even at the temperature of anatase-rutile transition. The phosphates cannot be removed by washing with water or diluted acids, but are extracted by basic solutions. The active sites for phosphate adsorption are hydroxyl groups and Lewis acid sites on the anatase surface, whereas part of the c.u.s. Ti4+ ions, which exhibit a weak acidity, remains free. Thermal treatment of samples modified by phosphoric acid leads to their dehydroxylation due to the recombination of hydrogen-bonded hydroxyl groups. For samples modified by NaH2PO4 part of the hydrogen ions are substituted by Na+, which leads to “dilution” of the hydroxyls and hinders their recombination. As a result, isolated OH groups, stable at 723 K, exist on the surface. The disappearance of the Lewis acidity on anatase after modification with phosphates allows the assumption that the role of phosphorus as a promoter in some titania-supported catalysts is to block the Ti4+ Lewis acid sites.
Cite:
Hadjiivanov K.I.
, Klissurski D.G.
, Davydov A.A.
Study of Phosphate-Modified TiO2 (Anatase)
Journal of Catalysis. 1989. V.116. N2. P.498-505. DOI: 10.1016/0021-9517(89)90116-4 WOS Scopus РИНЦ
Study of Phosphate-Modified TiO2 (Anatase)
Journal of Catalysis. 1989. V.116. N2. P.498-505. DOI: 10.1016/0021-9517(89)90116-4 WOS Scopus РИНЦ
Dates:
Submitted: | Mar 14, 1988 |
Accepted: | Nov 2, 1988 |
Published print: | Apr 1, 1989 |
Published online: | May 24, 2004 |
Identifiers:
Web of science | WOS:A1989U124600019 |
Scopus | 2-s2.0-45149146799 |
Elibrary | 30942197 |
Chemical Abstracts | 1989:413020 |
Chemical Abstracts (print) | 111:13020 |
OpenAlex | W2075207397 |