Brookite and anatase nanomaterial polymorphs of TiO2 synthesized from TiCl3

Leal, Juan H.; Cantu, Yvette; González, David; Parsons, Jasón G.

doi:10.1016/j.inoche.2017.07.014

Cited by 35 publications

(18 citation statements)

References 25 publications

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“…The band gap values depend on the crystalline phase of the materials. The values reported in the literature for the band gaps of pure anatase, brookite and rutile phases are 3.21, 3.13 and 3.0 eV, respectively [42]. As expected, the extrinsic conduction obtained though the doping of semiconductors reduces the distance between the bands of valence and conduction, provoking a decrease in the band gap.…”

Section: Tablesupporting

confidence: 58%

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SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

Buarque

Manzani

Scarpari

et al. 2018

Materials Research Bulletin

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The various synthesis conditions to obtain a material based on SiO 2-TiO 2 co-doped with Er 3+ /Yb 3+ /Eu 3+ were investigated, searching for those that present the greatest potential to improve the efficiency of solar cells. Conditions adjusted included heat-treatment temperatures, concentrations of matrix, and concentrations of dopants. Raman spectroscopy results demonstrated the effect of the annealing temperatures on the TiO 2 phase transition and the crystalline phase of the materials, which interfere with the photoluminescence of the materials. The band gap of the materials was evaluated by diffuse reflectance and it decreased due to the doping. The materials were able to absorb UV and IR energy and emit in the visible region, verified by the down conversion, up conversion and the double excitation of the materials. The results showed that the materials may be used as a strategy to use a greater portion of the solar spectrum, improving solar cell efficiency.

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Section: Tablesupporting

confidence: 58%

“…3. The materials containing Eu 3+ can absorb energy in the UV-vis region promoting the following transition states: 7 [21,22,42]. All samples presented photoluminescence, although their intensities of emission varied.…”

Section: Tablementioning

confidence: 99%

SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

Buarque

Manzani

Scarpari

et al. 2018

Materials Research Bulletin

View full text Add to dashboard Cite

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“…However, the stability fields of anatase and brookite overlap each other ( [40]; see their Figure 1). Therefore, during the synthesis of titanium dioxide, obtaining a mixture of two metastable low-temperature phases (brookite and anatase) is common, whereas serious efforts are required to selectively obtain anatase or brookite (e.g., [41,42] and many others). The leading role in the formation of a particular polymorph in chemical synthesis (and, most likely, in natural systems) acquires the characteristics of the fluid, including chemical composition, Eh, pH, etc.…”

Section: Discussionmentioning

confidence: 99%

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

et al. 2018

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This article is devoted to the geology of titanium-rich varieties of the Petyayan-Vara rare-earth dolomitic carbonatites in Vuoriyarvi, Northwest Russia. Analogues of these varieties are present in many carbonatite complexes. The aim of this study was to investigate the behavior of high field strength elements during the late stages of carbonatite formation. We conducted a multilateral study of titanium-and niobium-bearing minerals, including a petrographic study, Raman spectroscopy, microprobe determination of chemical composition, and electron backscatter diffraction. Three TiO 2 -polymorphs (anatase, brookite and rutile) and three pyrochlore group members (hydroxycalcio-, fluorcalcio-, and kenoplumbopyrochlore) were found to coexist in the studied rocks. The formation of these minerals occurred in several stages. First, Nb-poor Ti-oxides were formed in the fluid-permeable zones. The overprinting of this assemblage by residual fluids led to the generation of Nb-rich brookite (the main niobium concentrator in the Petyayan-Vara) and minerals of the pyrochlore group. This process also caused niobium enrichment with of early generations of Ti oxides. Our results indicate abrupt changes in the physicochemical parameters at the late hydro (carbo) thermal stage of the carbonatite formation and high migration capacity of Ti and Nb under these conditions. The metasomatism was accompanied by the separation of these elements.

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“…The redshift in band gap energy of TiO2 was observed by treatment at a higher temperature due to the increase of rutile phase content in the TiO2 photocatalysts [21,24,25]. The band gap energy of pure anatase and rutile phase was 3.2 eV and 3.0 eV, respectively [26,27]. Therefore, the increased rutile content after calcination at high temperature narrows the band gap.…”

Section: Characteristics Of the P25-tio 2 Catalystsmentioning

confidence: 98%

Photocatalytic Liquid-Phase Selective Hydrogenation of 3-Nitrostyrene to 3-vinylaniline of Various Treated-TiO2 Without Use of Reducing Gas

et al. 2019

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In this work, we investigate the effect of TiO2 properties on the photocatalytic selective hydrogenation of 3-nitrostyrene (3-NS) to 3-vinylaniline (3-VA). The P25-TiO2 photocatalysts were calcined at 600–900 °C using different gases (Air, N2, and H2) and characterized by XRD, N2 physisorption, XPS, UV-Vis, and PL spectroscopy. In the photocatalytic hydrogenation of 3-nitrostyrene in isopropanol, the selectivity of 3-vinylaniline of the treated TiO2 was almost 100%. A linear correlation between the 3-NS consumption rate and PL intensity was observed. Among the catalysts studied, P25-700-air, which possessed the lowest PL intensity, exhibited the highest photocatalytic activity due to the synergistic effect that resulted from its high crystallinity and the optimum amount of anatase/rutile phase content, leading to the reduction of the electron-hole recombination process.

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Brookite and anatase nanomaterial polymorphs of TiO2 synthesized from TiCl3

Cited by 35 publications

References 25 publications

SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

Photocatalytic Liquid-Phase Selective Hydrogenation of 3-Nitrostyrene to 3-vinylaniline of Various Treated-TiO2 Without Use of Reducing Gas

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