On the selective growth of titania polymorphs in acidic aqueous medium

Journal Article · Thu Dec 15 04:00:00 EST 2011 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2011.08.023· OSTI ID:22212371

Li, Haoguang ^[1]; Afanasiev, Pavel ^[2]

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1. Research Institute of Petroleum Processing, SINOPEC, 18 Xue Yuan Road, 100083 Beijing (China)
2. Institut de recherches sur la catalyse et l'environnement de Lyon UMR5256, CNRS-Universite de Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne cedex (France)

Highlights: Black-Right-Pointing-Pointer Mutual influence of peptizing and anions addition of titania hydrothermal growth was studied. Black-Right-Pointing-Pointer Sulfate and chloride control TiO{sub 2} phase or particles shape depending on the order of introduction. Black-Right-Pointing-Pointer A rationale of difference between sulfate and chloride effect was provided. Black-Right-Pointing-Pointer Ground state DFT and semi-empirical calculations of Ti species support the conclusions. -- Abstract: The influence of preparation conditions on the phase composition and morphology of titania was studied for the solids synthesized by hydrothermal treatment (HT) and peptizing of hydrous TiO{sub 2} sols in acidic medium. Mutual influence of peptizing and of additive anions (SO{sub 4}{sup 2-}, Cl{sup -}) on the nature of obtained polymorphs was for the first time systematically studied and coherently explained. The solids were characterized by XRD, Raman spectroscopy, and transmission electron microscopy. It was found that peptizing step preceding HT and the presence of anions play a crucial role for the selective formation of TiO{sub 2} anatase or rutile polymorphs. Low temperature peptizing leads to acicular rutile particles, whereas HT produces highly dispersed anatase. However if the HT was preceded by peptizing step, rutile was obtained in most cases. The influence of additives strongly depends on the moment of their introduction. Sulfate and chloride species can act as phase growth controllers, or as morphology modifiers. Sulfate hindered formation of rutile and favored anatase al low temperatures, but for already formed rutile seed, sulfate acted only as a shape controller. By contrast, chloride showed a strong tendency to promote rutile growth, whatever the conditions. A qualitative model was proposed explaining the effects observed, supported by ground state DFT and semi-empirical calculations of the aqueous Ti species.

• OSTI ID: 22212371
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 12 Vol. 46; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANIONS
CHLORIDES
GROUND STATES
RAMAN SPECTROSCOPY
RUTILE
SULFATES
SYNTHESIS
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION