Investigating the effect of dopant type and concentration on TiO2 powder microstructure via rietveld analysis

Rao, A. Sumadhura; Pundir, V.S.; Tiwari, Anamika; Padarthi, Yashwanth; Rao, Narendar V.; Aich, Shampa; Roy, B.

doi:10.1016/j.jpcs.2017.10.030

Cited by 14 publications

(8 citation statements)

References 80 publications

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“…Among the various growth conditions influencing the phase transformation in amorphous TiO 2 ( e.g. , type of substrate, deposition method, temperature, pressure, thermal treatments, and atmosphere), the grain size and thermal annealing rate are important in the A–R transformation process. − As stated by Zhang et al. , amorphous TiO 2 is an important precursor of single-phase nanocrystalline anatase.…”

Section: Discussionmentioning

confidence: 99%

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

et al. 2020

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The role played by oxygen vacancies and rare earth (RE) elements in the anatase-to-rutile (A–R) phase transformation of titanium dioxide (TiO2) is still a matter of controversy. Here, we report the A–R transformation of TiO2 thin solid films as obtained by ion beam sputtering a RE-decorated titanium target in an oxygen-rich atmosphere. The samples correspond to undoped, single-doped (Sm, Tm, and Tb), and codoped (Sm:Tb, Sm:Tm, and Sm:Tb:Tm) TiO2 films. In the as-prepared form, the films are amorphous and contain ∼0.5 at. % of each RE. The structural modifications of the TiO2 films due to the RE elements and the annealing treatments in an oxygen atmosphere are described according to the experimental results provided by Raman scattering, X-ray photoelectron spectroscopy, and optical measurements. The A–R transformation depends on both the annealing temperature and the characteristics of the undoped, single-doped, and codoped TiO2 films. As reported in the literature, the A–R transformation can be inhibited or enhanced by the presence of impurities and is mostly related to energetic contributions. The experimental results were analyzed, considering the essential and stabilizing role of the entropy of mixing in the A–R transformation due to the introduction of more and multiple quantum states originated in vacancies and impurities in the anatase phase.

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Section: Discussionmentioning

confidence: 99%

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

et al. 2020

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“…In contrast, the XRD pattern of the 1.5 Sc/TiO x sample does not undergo phase transformation with the increase of the calcination temperature, even until 800 °C. The increasing lattice energy derived from Sc doping facilitates the enhanced stability of the anatase phase because the introduced Sc can effectively inhibit the transformation of anatase into the rutile phase …”

Section: Resultsmentioning

confidence: 99%

“…The increasing lattice energy derived from Sc doping facilitates the enhanced stability of the anatase phase because the introduced Sc can effectively inhibit the transformation of anatase into the rutile phase. 44 The catalytic performances of these samples prepared under different calcination temperatures were also measured and are shown in Figure 9. It can be seen that the catalytic activity of the samples gradually decreases with the increase of calcination temperature for both bare TiO 2 and 1.5 Sc/TiO x samples.…”

Section: Methodsmentioning

confidence: 99%

Improved Catalytic Activity and Chemical Stability of Defective TiO₂ Catalysts by Doping Rare Earth Metal Sc for Propane Dehydrogenation

Shang

Liu

Lang

et al. 2021

Ind. Eng. Chem. Res.

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Herein, scandium (Sc)-doped TiO2 (nSc/TiO x ) catalysts were synthesized to investigate the impact of the doped rare earth metal Sc on its catalytic performance. It is found that appropriate Sc addition can facilitate the formation of oxygen vacancies (OVs) and active sites for the propane dehydrogenation (PDH) reaction, and the catalytic performance is evidently enhanced. However, excessive Sc clusters occur on the surface of the sample in the form of metal oxides as the amount of doped Sc increases, resulting in the decline of catalytic performance. The catalytic activity for the PDH reaction is closely related to the acidity of the Lewis acidic sites in nSc/TiO x catalysts. The introduction of Sc ions indeed enhances the lattice stability of the catalyst due to the formation of Ti–O–Sc bonds.

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“…In addition, the simultaneous presence of copper (acceptor) and chlorine (donor) can lead to the appearance of Coulomb interaction between them, i.e., to the formation of distributed donor-acceptor pairs, which can also contribute to the retention of not only Cu but also Cl inside the nanocrystals. In fact, in unalloyed oxides derived from chlorine raw materials, chlorine is removed for temperatures below 500 • C (Rao et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Peculiarities of Thermally Activated Migration of Subvalent Impurities in Cu-Doped Y-Stabilized ZrO2 Nanopowders Produced From Zr Oxychlorides

et al. 2018

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Investigating the effect of dopant type and concentration on TiO2 powder microstructure via rietveld analysis

Cited by 14 publications

References 80 publications

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

Improved Catalytic Activity and Chemical Stability of Defective TiO₂ Catalysts by Doping Rare Earth Metal Sc for Propane Dehydrogenation

Peculiarities of Thermally Activated Migration of Subvalent Impurities in Cu-Doped Y-Stabilized ZrO2 Nanopowders Produced From Zr Oxychlorides

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Investigating the effect of dopant type and concentration on TiO2 powder microstructure via rietveld analysis

Cited by 14 publications

References 80 publications

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO2 Thin Films Deposited by Ion Beam Sputtering

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO2 Thin Films Deposited by Ion Beam Sputtering

Improved Catalytic Activity and Chemical Stability of Defective TiO2 Catalysts by Doping Rare Earth Metal Sc for Propane Dehydrogenation

Peculiarities of Thermally Activated Migration of Subvalent Impurities in Cu-Doped Y-Stabilized ZrO2 Nanopowders Produced From Zr Oxychlorides

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Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO₂ Thin Films Deposited by Ion Beam Sputtering

Improved Catalytic Activity and Chemical Stability of Defective TiO₂ Catalysts by Doping Rare Earth Metal Sc for Propane Dehydrogenation