Anatase to rutile transformation in sol-gel titania by modification of precursor

Suresh, C.; Biju, V.M.; Mukundan, P.; Warrier, K. G. K.

doi:10.1016/s0277-5387(98)00077-1

Cited by 111 publications

(73 citation statements)

References 12 publications

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“…39,56 The system may be destabilized through the addition of water, which leads to a structurally weak network that can easily collapse upon calcination to form rutile. 69,70 From the spectroscopy results it can be seen that the addition of silver causes a reduction in the intensity of the COOstretches indicating that the titania formate bridging complex is becoming weaker in the presence of silver. This may lead to a structurally weak oligomer that upon calcination easily forms rutile at lower temperatures.…”

Section: Resultsmentioning

confidence: 99%

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

et al. 2010

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Anatase to rutile transition in an unmodified synthetic titania usually occurs at a temperature range of 600-700°C. Various methods such as addition of metallic and nonmetallic dopants and modifying the precursor have previously been reported to influence the anatase to rutile transition temperature. In the current study, the effect of addition of increasing amounts of silver to the extent of chelation of a formate group to a titanium precursor and the resulting effects on the transformation of anatase to rutile has been studied. The addition of silver (0, 1, 3, and 5 mol %) on the anatase to rutile transformation temperature has been systematically followed by Fourier transform infrared (FTIR), Raman, X-ray diffraction (XRD), differential scanning calorimetry, and X-ray photoelectron spectroscopy (XPS) studies. From the FTIR and Raman spectroscopy studies it was observed that the incorporation of silver caused a reduction in the intensity of the COO -stretches indicating that the titania formate bridging complex is becoming weaker in the presence of silver. XRD studies indicated an early rutile formation for the silver-doped samples. XRD of the samples calcined at 700°Cshowed that 5 mol % Ag TiO 2 contained both anatase (46%) and rutile (54%), whereas the undoped sample primarily consists of anatase (95%). At 800°C all silver doped samples converted to 100% rutile and the undoped TiO 2 consisted of both anatase (55%) and rutile (45%). XPS analysis showed that Ag 0 and Ag 2 O has been formed on the surface of the titania formate complex without calcination (>100°C) indicating that photo-oxidation has occurred. FTIR, Raman, and XPS studies confirmed that the presence of silver in the xerogel before calcination may be responsible for the reduction of the titanium formate bridge. It was concluded that the presence of silver (Ag 2 O and Ag 0 ) hindered bridging ligands, which resulted in a weakened titanium gel network. This structurally weakened gel network could easily be collapsed during calcination, and it favors an early rutile formation.

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Section: Resultsmentioning

confidence: 99%

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

et al. 2010

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“…Another method of measurement was employed by Suresh et al [139], who applied impedance spectroscopy to examine the anatase to rutile transformation. Since this method relies on the difference in resistivity between the two phases, it suffers two innate uncertainties associated with electrical resistivity measurement.…”

Section: Impedance Spectroscopymentioning

confidence: 99%

“…Since the particle size and surface area depend strongly on the preparation method, it would be misleading to interpret the photocatalytic performance solely in terms of the phase composition. As an example of the importance of the effect of the processing conditions on these parameters, variations in grain size, crystallite size, surface area, morphology, and phase distribution obtained during sol-gel synthesis have been observed to be highly dependent on the precursor solutes and solvents used [36,46,54], calcining temperatures [55,110,148,149], and pH [54,73,83,114,139,150].…”

Section: Rutile-anatase Mixturesmentioning

confidence: 99%

Review of the anatase to rutile phase transformation

2010

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Titanium dioxide, TiO 2 , is an important photocatalytic material that exists as two main polymorphs, anatase and rutile. The presence of either or both of these phases impacts on the photocatalytic performance of the material. The present work reviews the anatase to rutile phase transformation. The synthesis and properties of anatase and rutile are examined, followed by a discussion of the thermodynamics of the phase transformation and the factors affecting its observation. A comprehensive analysis of the reported effects of dopants on the anatase to rutile phase transformation and the mechanisms by which these effects are brought about is presented in this review, yielding a plot of the cationic radius versus the valence characterised by a distinct boundary between inhibitors and promoters of the phase transformation. Further, the likely effects of dopant elements, including those for which experimental data are unavailable, on the phase transformation are deduced and presented on the basis of this analysis.

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“…Modification of titanium alkoxides with chelating agents is known to promote thermally stable anatase phase at increased temperatures (>800 • C) [36,37]. However, the employment of chelating agents for the synthesis of stable anatase typically involves the formation of bridging structures that promote the formation of polymeric chains with extensive cross linking [38].…”

Section: Tablementioning

confidence: 99%

Effect of N-doping on the photocatalytic activity of sol–gel TiO2

Nolan

Synnott

Seery³

et al. 2012

Journal of Hazardous Materials

192

107

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Anatase to rutile transformation in sol-gel titania by modification of precursor

Cited by 111 publications

References 12 publications

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

Review of the anatase to rutile phase transformation

Effect of N-doping on the photocatalytic activity of sol–gel TiO2

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Anatase to rutile transformation in sol-gel titania by modification of precursor

Cited by 111 publications

References 12 publications

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO2

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO2

Review of the anatase to rutile phase transformation

Effect of N-doping on the photocatalytic activity of sol–gel TiO2

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Product

Resources

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A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂