Iron doped titania thin films prepared by spin coating

Nakaruk, Auppatham; Lin, Cheng‐Hsiung; Koshy, Pramod; Sorrell, Charles C.

doi:10.1179/1743676111y.0000000065

Cited by 12 publications

(3 citation statements)

References 34 publications

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“…These data are consistent with the Raman data such that, for the doped thin films, the crystallinity increased with increasing doping levels after an initial decrease. Owing to the lower precision of GAXRD relative to both XRD 50 and laser Raman microspectroscopy 51 and the absence of a standard 52 for peak position normalization, examination of the peak shifts was not meaningful. However, the solubility of the dopants could be expected to cause such shifts, as seen previously from the Raman data.…”

Section: Inorganic Chemistrymentioning

confidence: 99%

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

et al. 2016

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The present work reports data for the mineralogical and chemical properties of anatase thin films individually doped or codoped with chromium and vanadium, fabricated by sol-gel spin coating on glass substrates and annealing at 450 °C for 2 h. X-ray photoelectron spectroscopy data indicated the presence of Ti(4+), Ti(3+), Cr(3+), and possibly Cr(4+) in the Cr-doped thin films; Ti(4+), Ti(3+), V(3+), V(4+), and possibly V(5+) in the V-doped thin films; and Ti(4+), Ti(3+), Cr(3+), Cr(4+), V(3+), V(4+), and possibly V(5+) in the codoped thin films. While the thermodynamically stable valences Ti(4+), Cr(3+), and V(5+) would be expected to have formed, the presence of the nonequilibrium valences Ti(3+), Cr(4+), V(3+), and V(4+) is considered to have resulted from intervalence charge transfer for the Cr-doped and V-doped systems but from multivalence charge transfer (MVCT) for the codoped system. The latter phenomenon, which is introduced as a new conceptual term, describes the nature of the mutual exchange of electrons during valence changes of both dopant (Cr, V) and matrix (Ti) ions during annealing. In the present case, MVCT appears to be a transient metastable condition that acts during annealing, but subsequent UV irradiation can alter its effects.

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Section: Inorganic Chemistrymentioning

confidence: 99%

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

et al. 2016

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“…However, the band gap of anatase TiO 2 has been reported to cover a wide range of 3.23–3.59 eV [ 39 ]. Although the determined value is within this range, it is possible that it reflects silicon contamination, which is known to increase the band gap [ 9 , 43 ]. The even higher band gap of the TiO 2 -vetiver core–shell is likely to derive from the previously mentioned effect of carbon in the partial reduction of TiO 2 .…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic Degradation of Organic Dye under UV‐A Irradiation Using TiO2‐Vetiver Multifunctional Nano Particles

et al. 2017

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The properties and photocatalytic performance of anatase nanoparticles of pure TiO2 and a core–shell structure of TiO2 on calcined vetiver grass leaves have been compared. Samples were fabricated by sol-gel and heating at 450 °C for 5 h. The comparison was based on data for X-ray diffraction (XRD), UV-Vis spectrophotometry, photoluminescence, transmission electron microscopy, specific surface area measurement, pore volume assessment, and methylene blue degradation testing. The results showed that the pure TiO2 consisted of agglomerated equiaxed nanoparticles of individual grain sizes in the range 10–20 nm. In contrast, the TiO2-vetiver composite exhibited a core–shell structure consisting of a carbonaceous core and TiO2 shell of thickness 10–15 nm. These features influenced the photocatalytic performance in such a way that the lower cross-sectional area, greater surface area, and higher pore volume of the TiO2 shell increased the number of active sites, reduced the charge carrier diffusion distance, and reduced the recombination rate, thereby improving the photocatalytic activity. This improvement derived from morphological characteristics rather than crystallographic, semiconducting, or optical properties. The improved performance of the TiO2-vetiver core–shell was unexpected since the X-ray diffraction data showed that the crystallinity of the TiO2 was lower than that of the pure TiO2. These outcomes are attributed to the reducing effect of the carbon on the TiO2 during heating, thereby facilitating the formation of oxygen vacancies, which enhance charge separation and hence photocatalysis by TiO2.

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“…To overcome these disadvantages, research has focused on doping to produce suitable midgap energy levels within the band gap for effective band gap reduction and to reduce the recombination time by promoting faster transfer of charge carriers , to the conduction band. Both metallic and nonmetallic dopants, such as La 3+ , Fe 3+ , Cu 2+ , Ag + , S 2– , C 4± , and N 3– , have been investigated for their potential to improve the photocatalytic performance. − Compared to other metallic dopants, molybdenum (Mo) is one of the most attractive owing to its multiple valence states and the associated, potential, multiple, shallow-donor levels within the band gap Table summarizes work on Mo single-doping and codoping of TiO 2 from literature.…”

Section: Introductionmentioning

confidence: 99%

Structural and Microstructural Effects of Mo³⁺/Mo⁵⁺ Codoping on Properties and Photocatalytic Performance of Nanostructured TiO₂ Thin Films

et al. 2019

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Mo 3+ /Mo 5+ equally codoped TiO 2 thin films (0.050−0.100 mol % individually) were fabricated by spin coating on polished fused silica glass substrates followed by annealing at 450 °C for 2 h. The highly transparent (>80%) films consisted of poorly crystallized single-crystal anatase, where interstitial solid solubility decreases the lattice parameters, with a reversed trend at the highest codoping level arising from supersaturation and V O •• formation. The crystallinities correlate with the alternating trends of peak intensities and shifts in both the glancing angle X-ray diffraction and Raman data. X-ray photoelectron spectroscopy data reveal the absence of any valence changes, indicating that intervalence charge transfer is not relevant. Although there are four potential midgap states that may alter the E g (Mo i, and V Ti ⁗), any effects from them on the performance would be mitigated by the annihilation of the charge-compensating V O ••. As the E g values correlate with the lattice parameters, the principal driver of the E g is the residual lattice compressive strain. However, the photocatalytic performance is principally a function of the crystallinity.

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Iron doped titania thin films prepared by spin coating

Cited by 12 publications

References 34 publications

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

Photocatalytic Degradation of Organic Dye under UV‐A Irradiation Using TiO2‐Vetiver Multifunctional Nano Particles

Structural and Microstructural Effects of Mo³⁺/Mo⁵⁺ Codoping on Properties and Photocatalytic Performance of Nanostructured TiO₂ Thin Films

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Iron doped titania thin films prepared by spin coating

Cited by 12 publications

References 34 publications

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO2

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO2

Photocatalytic Degradation of Organic Dye under UV‐A Irradiation Using TiO2‐Vetiver Multifunctional Nano Particles

Structural and Microstructural Effects of Mo3+/Mo5+ Codoping on Properties and Photocatalytic Performance of Nanostructured TiO2 Thin Films

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Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

Multivalence Charge Transfer in Doped and Codoped Photocatalytic TiO₂

Structural and Microstructural Effects of Mo³⁺/Mo⁵⁺ Codoping on Properties and Photocatalytic Performance of Nanostructured TiO₂ Thin Films