Surface acidity and properties of Titania-sililca catalysts

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm00055a011· OSTI ID:160079

Galan-Fereres, M; Alemany, L J; Mariscal, R ^[1]

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1. Instituto de Catalisis y Petrolequimica, Madrid (Spain)

Titania-supported redox oxides constitute one of the most important categories of catalysts for the selective catalytic reduction (SCR) of NO{sub x}. Titania-coated silica microspheres containing between 8 and 48 wt % TiO{sub 2} have been prepared by the homogeneous precipitation of TiCl{sub 3} with a diluted ammonia solution up to a final pH close to 7. All these TiO{sub 2}-SiO{sub 2} materials were physically characterized by X-ray diffraction, UV-visible reflectance, Raman, Fourier transform infrared, and photoelectron spectroscopic techniques. Calcination of the silica-supported precipitates leads to the formation of titanium dioxide. These TiO{sub 2} species are scattered on the surface as small crystals of anatase. Their structures become better defined as the titania loading increases. It was also observed that the TiO{sub 2}-SiO{sub 2} oxides show much stronger acidic properties than the single TiO{sub 2} and SiO{sub 2} oxides. Broensted acid sites appear to be associated with the interface between octahedral titanium sites and silica. The infrared spectra of chemisorbed ammonia was very useful to characterize acid properties in these materials. 49 refs., 9 figs., 1 tab.

• Sponsoring Organization: USDOE
• OSTI ID: 160079
• Journal Information: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 7 Vol. 7; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ABSORPTION SPECTROSCOPY
AMMONIA
BROENSTED ACIDS
CALCINATION
CATALYST SUPPORTS
CHEMISORPTION
PRECIPITATION
RAMAN SPECTROSCOPY
SILICA
SORPTIVE PROPERTIES
STRUCTURAL CHEMICAL ANALYSIS
TITANIUM OXIDES
X-RAY DIFFRACTION