Red shifts of the Eg(1) Raman mode of nanocrystalline TiO2:Er monoliths grown by sol–gel process

Palomino-Merino, R.; Trejo-García, P.; Portillo-Moreno, O.; Jiménez‐Sandoval, S.; Tomás, S.A.; Zelaya-Ángel, O.; Lozada‐Morales, R.; Castaño, V. M.

doi:10.1016/j.optmat.2015.04.042

Cited by 31 publications

(11 citation statements)

References 29 publications

(41 reference statements)

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“…[13] Ther edshifti nt he anatase B 1g signal at approximately 401 cm À1 may be due to the stress produced in the nanotubes with the growing sizes of the other phases. [49] Thus,t he Ramans pectra of the hydrogen-annealed samples clearly confirmt he presence of three phases in the TiO 2 and reductive TiO 2 samples.…”

Section: Resultsmentioning

confidence: 60%

“…The redshift in the anatase E g mode at 148 cm −1 in the hydrogen‐annealed TiO 2 samples hints towards the transformation of anatase into rutile, as the rutile B 1g mode appears around 143 cm −1 and it is difficult to distinguish . The redshift in the anatase B 1g signal at approximately 401 cm −1 may be due to the stress produced in the nanotubes with the growing sizes of the other phases . Thus, the Raman spectra of the hydrogen‐annealed samples clearly confirm the presence of three phases in the TiO 2 and reductive TiO 2 samples.…”

Section: Resultsmentioning

confidence: 74%

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Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

et al. 2017

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We report the first demonstration of hydrogen‐annealed triphase TiO2 nanotubes (anatase–rutile–brookite) (T‐ARB) as a visible‐light‐active photocatalyst for water splitting with high quantum efficiency. As‐synthesized T‐ARB was annealed under hydrogen atmosphere at 250 and 450 °C for 2 h. We found that the tubular structures were retained in the hydrogenated TiO2 samples. It was observed that the concentrations of Ti3+ and the oxygen vacancies and their distribution significantly increased with respect to the hydrogen annealing temperature. Such changes in defects were found to be critical in enhancing the photocatalytic activity of the hydrogen‐annealed triphase TiO2 nanotubes. The triphase TiO2 nanotubes hydrogen annealed at 450 °C were 16 times more efficient than pristine TiO2. Such an increase in the photocatalytic activity was explained by a triphase band diagram with defect states below the conduction band of each phase, which facilitated visible‐light activity and easy transfer of charge carriers from one phase to another. Our study showed that the well‐designed multiphase construction with oxygen vacancies enhanced the photocatalytic activity tremendously owing to the presence of a higher number of phase junctions.

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Section: Resultsmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 74%

Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

et al. 2017

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“…7 The TO and LO modes presented obvious "red shifts" of 7 and 27 cm −1 , respectively, which were mainly related to the material size effect and structural defects. 32 Nanowhiskers were present between the macroscopic and atomic levels and produced a red shift of less than 10 cm −1 . 33 In addition, the two shoulder peaks observed between the TO and LO modes (860 and 900 cm −1 ) indicated the presence of numerous defects.…”

Section: ■ Results and Discussionmentioning

confidence: 97%

“…The 789 and 945 cm –1 readings were the optical phonon (TO) mode and longitudinal phonon (LO) mode, respectively, and they correspond to the zone–center TO mode at 796 cm –1 and zone–center LO mode at 972 cm –1 . The TO and LO modes presented obvious “red shifts” of 7 and 27 cm –1 , respectively, which were mainly related to the material size effect and structural defects . Nanowhiskers were present between the macroscopic and atomic levels and produced a red shift of less than 10 cm –1 .…”

Section: Resultsmentioning

confidence: 99%

Growth of SiC Whiskers onto Carbonizing Coir Fibers by Using Silicon Slurry Waste

Cao

Xiang

et al. 2017

ACS Sustainable Chem. Eng.

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To reduce environmental pollution and waste of resources, it is very important to recycle valuable materials in silicon slurry waste (SSW). We report a novel method for the rapid preparation of SiC nanowhiskers by spark plasma (SP) assisted thermal treatment using SSW as the silicon source. In the preparation process, coir fibers were used as the carbon source and whisker growth substrate. At 1100–1300 °C, carbon-rich tadpole-like 3C–SiC whiskers with Fe catalyst caps were prepared by the vapor–liquid–solid growth mechanism. At 1400–1600 °C, carbon-rich, stick-like 3C–SiC whiskers without Fe catalyst caps with aspect ratios of about 40, and diameters of about 50 nm were prepared by the vapor–solid growth mechanism. The SiC whiskers grew along the [111] direction on the (111) plane at different temperatures. At the optimum temperature of 1500 °C, the silicon in SSW reacted completely, and SiC whiskers with good morphology were prepared. Furthermore, the photoluminescence (PL) spectra of SiC whiskers showed strong blue-violet emission at 450 nm. Accordingly, this study provides an environmentally friendly method for preparing SiC whiskers.

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“…Characteristic peaks of TiO 2 (phonon modes related with anatase phase) are identified at 142 cm -1 (E g (1) ), 194 cm -1 (E g (2) ), 396 cm -1 (B 1g (1) ), 516 cm -1 (A 1g(1) + B 1g (2) ) and 636 cm -1 (E g (3) ) [30].…”

Section: Influence Of Tiomentioning

confidence: 99%

Preparation of KOH‐doped PVA/PSSA Solid Polymer Electrolyte for DMFC: The Influence of TiO₂ and PVP on Performance of Membranes

Oliveira

Nascimento

2016

Fuel Cells

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The development of low cost alkaline anion solid exchange membranes requires high ionic conductivity, low liquid uptake, strong mechanical properties and chemical stability. PVA/PSSA blends cross-linked with glutaraldehyde and decorated with titanium dioxide nanoparticles introduce advantages relative to the pristine membrane of PVA and PVA/PVP membranes due to their improved electrical response and low methanol uptake/ swelling ratio allowing their use in alkaline direct methanol fuel cells.

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Red shifts of the Eg(1) Raman mode of nanocrystalline TiO2:Er monoliths grown by sol–gel process

Cited by 31 publications

References 29 publications

Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

Growth of SiC Whiskers onto Carbonizing Coir Fibers by Using Silicon Slurry Waste

Preparation of KOH‐doped PVA/PSSA Solid Polymer Electrolyte for DMFC: The Influence of TiO₂ and PVP on Performance of Membranes

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Red shifts of the Eg(1) Raman mode of nanocrystalline TiO2:Er monoliths grown by sol–gel process

Cited by 31 publications

References 29 publications

Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

Marginally Hydrogenated Triphasic Titania Nanotubes for Effective Visible‐Light Photocatalytic Hydrogen Generation

Growth of SiC Whiskers onto Carbonizing Coir Fibers by Using Silicon Slurry Waste

Preparation of KOH‐doped PVA/PSSA Solid Polymer Electrolyte for DMFC: The Influence of TiO2 and PVP on Performance of Membranes

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Product

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Preparation of KOH‐doped PVA/PSSA Solid Polymer Electrolyte for DMFC: The Influence of TiO₂ and PVP on Performance of Membranes