Effect of tin dioxide doping on rutile phase formation in sol-gel-derived nanocrystalline titania powders

Ding, Xuejia; Qi, Zhenzhong; He, Yuandi

doi:10.1016/0965-9773(94)90018-3

Cited by 21 publications

(10 citation statements)

References 9 publications

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“…(6) The surface SiO 2 content determined by XPS analysis increased with increased heating temperature, suggesting that the added SiO 2 in the TiO 2 xerogels was expelled from the interior to the surface where it formed an amorphous SiO 2 surface layer on the anatase particles. (7) This surface amorphous SiO 2 layer acted to suppress the anatase-to-rutile phase transition by preventing direct contact between the anatase particles in a mechanism similar to that reported for the ␥-Al 2 O 3 -to-␣-Al 2 O 3 phase transition in the presence of SiO 2 additions.…”

Section: Discussionmentioning

confidence: 59%

“…However, the gels dried at 60°C showed broad XRD peaks of a rutile-type phase as well as weak peaks of anatase. The reason for this unusual result was not clearly discussed by Ding et al, 7 but the added SnO 2 component may have acted as a semicoherent surface to form a rutile-type phase, because crystalline SnO 2 has the rutile structure. In this case, the effect of Sn 4ϩ on the anatase-to-rutile phase transition could not be directly compared with other work.…”

Section: Introductionmentioning

confidence: 93%

“…Although the only thermodynamically stable phase is rutile, the initial crystalline TiO 2 phase generally formed in a sol-gel preparation is anatase, which transforms to rutile when calcined at high temperatures. Because this phase transition is from a metastable to a stable phase, similar to that of ␥-Al 2 O 3 to ␣-Al 2 O 3 , the transition temperature is influenced by cation impurities, [1][2][3][4][5][6][7][8][9] anion impurities, 10,11 grain size, 12 reaction atmosphere, 13,14 and other factors. 15 With respect to cation impurities, the incorporation of foreign cations of valence lower than 4ϩ is considered to accelerate the transition, because it provides a charge compensation mechanism by the formation of oxygen vacancies that enhance the transport of atoms in the anatase structure and accelerate the phase transition.…”

Section: Introductionmentioning

confidence: 99%

“…The effects of 4ϩ cations larger than Ti 4ϩ (Sn 4ϩ and Zr 4ϩ ) on the anatase-to-rutile phase transition have been investigated previously. Ding et al 7 prepared tin-containing TiO 2 gels by hydrolyzing a mixture of titanium tetrabutoxide and tin chloride pentahydrate dissolved in ethanol using HCl as the catalyst. However, the gels dried at 60°C showed broad XRD peaks of a rutile-type phase as well as weak peaks of anatase.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Silica Additive on the Anatase‐to‐Rutile Phase Transition

Okada

Yamamoto

Kameshima

et al. 2001

Journal of the American Ceramic Society

266

154

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The effect of SiO 2 addition on the anatase-to-rutile phase transition was investigated by DTA, XRD, FTIR, and XPS. TiO 2 xerogels containing SiO 2 up to 20 mol% were prepared by mixing and hydrolyzing titanium tetraisopropoxide (TTIP) and tetraethylorthosilicate (TEOS) with HNO 3 as a catalyst. With increased amounts of SiO 2 in the xerogels, the following results were obtained: (1) the crystallization temperature of anatase increased from 415°C in pure TiO 2 to 609°C in 20-mol%-SiO 2 -containing xerogel in the DTA curves; (2) the formation temperature of rutile, according to quantitative XRD analysis, increased with increased SiO 2 content up to 5 mol% SiO 2 but became constant at higher SiO 2 contents; (3) the crystallinity of anatase became lower; and (4) the lattice parameter a of the anatase decreased slightly, but the parameter c decreased greatly up to 20 mol% SiO 2 . Although the added silicon atoms were considered from these results to be incorporated into the amorphous TiO 2 and anatase structures, the 29 Si MAS NMR spectra of the xerogels containing 10 mol% SiO 2 showed only tetrahedral silicon, with no indication of silicon in octahedral coordination. When calcined at higher temperatures, the xerogel showed polymerization of the SiO 4 tetrahedra in the NMR spectra and the Si-O-Si vibration in the FTIR spectra. The chemical composition of the xerogel surfaces, measured using XPS, showed increased SiO 2 content with increased calcining temperature, indicating the expulsion of silicon from inside the particles to form an amorphous SiO 2 surface layer. The formation of this amorphous SiO 2 surface layer was considered to be important in retarding the anataseto-rutile phase transition by suppressing diffusion between anatase particles in direct contact and limiting their ability to act as surface nucleation sites for rutile. These effects of silicon additions were similar to those observed in the ␥-Al 2 O 3 -to-␣-Al 2 O 3 transition.

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Section: Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Silica Additive on the Anatase‐to‐Rutile Phase Transition

Okada

Yamamoto

Kameshima

et al. 2001

Journal of the American Ceramic Society

266

154

View full text Add to dashboard Cite

show abstract

“…In this case, the direct transformations of gels to rutile can be the dominant crystallization process. Moreover, the rutile can nucleate based on the precipitated SnO 2 fine particles [41,42] because the SnO 2 crystal (a = 4.737 Å , c = 3.186 Å ) has similar structure and lattice constants to those of rutile. Consequently, the nucleation and growth of rutile in sample 10ST can be sufficiently improved due to the greatly precipitated SnO 2 fine particles.…”

Section: Effect Of Sn 2+ /Sn 4+ On Transformation Ratesmentioning

confidence: 98%

The phase transformation behaviors of Sn2+-doped Titania gels

Shi

Liang

Jin

et al. 2007

Journal of Non-Crystalline Solids

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Sol‐Gel Inks for Direct‐Write Assembly of Functional Oxides

2007

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The ability to pattern oxide structures at the microscale in both planar and three-dimensional forms is important for a broad range of emerging applications, including sensors, [1][2][3] micro-fuel cells [4,5] and batteries, [6,7] photocatalysts, [8,9] solar arrays, [10,11] and photonic bandgap (PBG) materials. [12,13] Here, we report the fabrication of micro-periodic oxide structures by direct-write assembly of sol-gel inks. Specifically, we create both planar and three-dimensional (3D) architectures composed of submicron features, which are converted to the desired oxide phase upon calcination. Atomic force microscopy (AFM) and optical reflectivity measurements acquired on these micro-periodic structures reveal their high degree of structural uniformity. Several techniques have recently been introduced for patterning materials, including colloidal self-assembly, [14] holographic lithography, [15,16] and direct laser [17,18] and ink writing [19][20][21] approaches. Unfortunately, these approaches, apart from two notable exceptions, [22,23] are confined to polymeric systems that lack the specific functionality required for a given application. As a consequence, the as-patterned structures require additional processing step(s) to produce the desired functional replicas. For example, 3D micro-fuel cells [24] and photonic bandgap materials [12,13,25,26] with inverse face centered cubic (fcc) structures have been templated from colloidal crystals, while silicon photonic crystals in both normal and inverse woodpile architectures have been templated from polymer structures produced by direct laser [27] and ink [28,29] writing, respectively.To circumvent the need for complicated templating schemes, we are developing a family of sol-gel inks that enable the direct ink writing (DIW) of functional oxides at the microscale. DIW is a layer-by-layer assembly technique, in which materials are fabricated in arbitrary planar and 3D forms with lateral dimensions that are two orders of magnitude lower than those achieved by ink-jet printing.[30] Paramount to our approach is the creation of concentrated inks that can be extruded through fine deposition nozzles as filament(s), which then undergo rapid solidification to maintain their shape even as they span gaps in underlying layer(s). Unlike our prior efforts based on polyelectrolyte inks [20,21] that require a reservoir-induced coagulation to enable 3D printing, these new inks can be directly printed in air providing exquisite control over the deposition process (e.g., the ink flow can now be started/stopped repeatedly during assembly). We first demonstrate this new ink design by creating a solgel precursor solution based on a chelated titanium alkoxide, titanium diisopropoxide bisacetylacetonate (TIA). TIA has an octahedral coordination of two isopropoxide and two acetylacetone (acac) groups about a central titanium (Ti) atom (Fig. 1a). This molecular structure is ideal, as it leads to the formation of soluble linear chains upon hydrolysis and condensation of the labile isopropox...

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Effect of tin dioxide doping on rutile phase formation in sol-gel-derived nanocrystalline titania powders

Cited by 21 publications

References 9 publications

Effect of Silica Additive on the Anatase‐to‐Rutile Phase Transition

Effect of Silica Additive on the Anatase‐to‐Rutile Phase Transition

The phase transformation behaviors of Sn2+-doped Titania gels

Sol‐Gel Inks for Direct‐Write Assembly of Functional Oxides

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