Study of the Zirconium and Silicon Homovalent Dopants Insertion on the Structure and Bandgap Energy of Titanium Dioxide Powders

2018 ◽  
Vol 930 ◽  
pp. 67-72
Author(s):  
Hiana Muniz Garcia ◽  
Eduardo Felipe de Carli ◽  
Natali Amarante da Cruz ◽  
Jusinei Meireles Stropa ◽  
Lis Regiane Vizolli Favarin ◽  
...  
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Performance Enhancement ◽  
Thermal Analyses ◽  
Rutile Phase ◽  
Bandgap Energy ◽  
Structural Effects ◽  
Structural Refinement ◽  
Anatase Structure ◽  
Atomic Coordinates

The reconstructive transformation occurring during the anatase-to-rutile phase transition can be observed through adequate techniques such as Thermal Analyses and Z-ray diffractometry followed by structural refinement. The typical photonic properties of titanium dioxide photocatalysts depend on the anatase structure and how the modifiers can provide their performance enhancement. In the present work, we investigate the structural effects caused by the simultaneous homovalent modification on the anatase structure in order to understand the mechanisms of the anatase-to-rutile phase transition in terms of the atomic coordinates and the lattice parameters. The refined structures along the calcination temperature from 500 to 900 oC suggest the oxygen bonds are strongly affected in unmodified anatase in order to destroy and rebuilt the crystal structure and lead to the rutile phase formation above 700 oC, unless some modifier pairs stabilize them.

Effect of Iron and Vanadium on the Phase Transition of Titanium Dioxide Obtained by Polymeric Precursor Method

2016 ◽  
Vol 881 ◽  
pp. 18-23
Author(s):  
Eduardo Felipe de Carli ◽  
Maycon dos Santos ◽  
Natali Amarante da Cruz ◽  
Daniela Cristina Manfroi ◽  
Jusinei Meireles Stropa ◽  
...  
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Phase Formation ◽  
Anatase Phase ◽  
Synthesis Method ◽  
Rutile Phase ◽  
Polymeric Precursor Method ◽  
Polymeric Precursor ◽  
Precursor Method ◽  
Powder Samples

The titanium dioxide phase formation is dependent on the synthesis method, temperature of calcination and modifiers insertion. By using chemical methods, such as Polymeric Precursor Method, the organic impurities or extrinsic defects caused by doping play an important rule on the formation of precursor structure before the phase crystallization above 500 oC. Some dopants can change the decomposition mechanism of the precursor, which affects the anatase-rutile phase transition. In this work, the Polymeric Precursor Method was used to synthesize titanium dioxide powder samples in order to investigate the effects of iron (III) and vanadium (V) dopants on the phase formation. Through thermal analysis of polymeric precursors and X-ray diffractometry for calcined powder samples it was possible to show the existence of antagonistic effects for both investigated dopants. While the iron doping reduces the anatase phase tetragonality and delays the rutile phase conversion, the vanadium one changes the mechanism of decomposition of polymeric precursor and leads to more amount of rutile phase.

Structural and Thermal Studies of Titanium Dioxide Gel Modified with Anatase Isostructural Zircon Silicate

2018 ◽  
Vol 930 ◽  
pp. 73-78
Author(s):  
Eduardo Felipe de Carli ◽  
Natali Amarante da Cruz ◽  
Hiana Muniz Garcia ◽  
Jusinei Meireles Stropa ◽  
Lis Regiane Vizolli Favarin ◽  
...  
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Rietveld Method ◽  
Anatase Phase ◽  
Sol Gel ◽  
Thermal Studies ◽  
Rutile Phase ◽  
Structural Rearrangements ◽  
X Ray Diffraction ◽  
X Ray

Important changes in anatase crystal structure are responsible for the consequent anatase-to-rutile phase transition in titanium dioxide powders. In order to investigate several structural rearrangements occurring in anatase phase obtained by hydrolysis-based method such as Sol-Gel method the X-ray diffraction techniques followed by Rietveld method seems to better approach. Several alterations in anatase lattice parameters can occur by doping insertion and the investigation of isostructural zircon silicate can provide interesting ones. In the present paper, the monitoring of anatase structure reordering and the consequent anatase-to-rutile phase transition along the thermal treatment up to higher temperatures were monitored carrying out DSC and XRD characterizations. The insertion of 6 mol% of zircon silicate leads to the fully anatase stabilization up to 900 °C due the control of ordering process, even that a continuous increasing in anatase tetragonality is present during the entire process. We can conclude the reconstructive anatase-to-rutile phase transition is delayed to very higher temperatures can consequence of more stable cross-linked metal oxide bond in anatase phase.

scholarly journals New approach of modifying the anatase to rutile transition temperature in TiO2 photocatalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 95232-95238 ◽  
Author(s):  
Ciara Byrne ◽  
Rachel Fagan ◽  
Steven Hinder ◽  
Declan E. McCormack ◽  
Suresh C. Pillai
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Transition Temperature ◽  
Rutile Phase ◽  
Tio2 Photocatalysts ◽  
New Approach

In pure synthetic titanium dioxide, the anatase to rutile phase transition usually occurs between the temperatures of 600 °C and 700 °C.

Effect of the Iron Doping on the Thermal Decomposition of the Polymeric Precursor for the Titanium Dioxide Powder Synthesis

2014 ◽  
Vol 798-799 ◽  
pp. 211-216 ◽  
Author(s):  
Silvanice A. Lopes ◽  
Natali A. Cruz ◽  
Daniela C. Manfroi ◽  
Rafael Gomes Dias ◽  
Margarete S. Silva ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Decomposition ◽  
Titanium Dioxide ◽  
Anatase Phase ◽  
Visible Region ◽  
Rutile Phase ◽  
Polymeric Precursor Method ◽  
Polymeric Precursor ◽  
Powder Synthesis ◽  
Precursor Method

The Polymeric Precursor Method has proved suitable for synthesizing reactive powders using low temperatures of calcination, especially when compared with conventional methods. However, during the thermal decomposition of the polymeric precursor the combustion event can be releases an additional heat that raises the temperature of the sample in several tens of degrees Celsius above the set temperature of the oven. This event may be detrimental to some material types, such as the titanium dioxide semiconductor. This ceramic material has a phase transition at around 600 ° C, which involves the irreversible structural rearrangement, characterized by the phase transition from anatase to rutile TiO2 phase. The control of the calcination step then becomes very important because the efficiency of the photocatalyst is dependent on the amount of anatase phase in the material. Furthermore, use of dopant in the material aims to improve various properties, such as increasing the absorption of radiation and in the time of the excited state, shifting of the absorption edge to the visible region, and increasing of the thermal stability of anatase. In this work, samples of titanium dioxide were synthesized by the Polymeric Precursor Method in order to investigate the effect of Fe (III) doping on the calcination stages. Thermal analysis has demonstrated that the Fe (III) insertion at 1 mol% anticipates the organic decomposition, reducing the combustion event in the final calcination. Furthermore, FTIR-PAS, XRD and SEM results showed that organic matter amount was reduced in the Fe (III)-doped TiO2 sample, which reduced the rutile phase amount and increased the reactivity and crystallinity of the powder samples.

scholarly journals Structural Aspects of Anatase to Rutile Phase Transition in Titanium Dioxide Powders Elucidated by the Rietveld Method

2017 ◽  
Author(s):  
Alberto Adriano Cavalheiro ◽  
Lincoln Carlos Silva de Oliveira ◽  
Silvanice Aparecida Lopes dos Santos
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Rietveld Method ◽  
Rutile Phase ◽  
Structural Aspects

Impact of medical titanium implant surface on the efficiency of fibrointegration

2020 ◽  
pp. 50-55
Author(s):  
T. R. Davydova ◽  
А. I. Shaikhaliev ◽  
D. A. Usatov ◽  
G. A. Gasanov ◽  
R. S. Korgoloev
Keyword(s):  
Surface Roughness ◽  
Titanium Dioxide ◽  
Rough Surface ◽  
Soft Tissues ◽  
Titanium Implant ◽  
Implant Surface ◽  
Anatase Structure ◽  
Bioactive Coating ◽  
Cell Structures ◽  
Titanium Alloy Ti6al4v

The aim of this study was to study the effect of surface branching of titanium endoprostheses on the efficiency of fibrointegration. The object of the study was samples of titanium alloy Ti6Al4V in the form of disks with a diameter of 5 mm and a thickness of 1 mm with various surface treatments: 1) samples with a rough surface after sandblasting; 2) samples with a rough surface after sandblasting with a bioactive coating of titanium dioxide TiO2 with anatase structure. The study of surface roughness was carried out by profilometry. Evaluation of the spreading and proliferation of cells on the surface of test samples, as well as evaluation of the effectiveness of fibrointegration was carried out according to standard methods using scanning electron microscopy. During the experiments, mesinchymal stem cells were sown on test samples and the test samples were introduced into the soft tissues of experimental animals. Based on the results obtained, it was concluded that the technology of forming rough surfaces by sandblasting does not provide high uniformity and reproducibility in the nanometer range and, apparently, another method for obtaining a rough surface should be chosen. The application of a bioactive coating of titanium dioxide TiO2 with the anatase structure to the surface of titanium endoprostheses increases the efficiency of fibrointegration, however, primarily the fibrointegration of titanium endoprostheses depends on their surface roughness, which determines the concentration of cell structures, the intensity of their adhesion and the ability to fibrointegrative process.

scholarly journals Synthesis and photocatalytic properties of Sn–TiO2 nanomaterials

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060018
Author(s):  
E. M. Bayan ◽  
T. G. Lupeiko ◽  
L. E. Pustovaya ◽  
M. G. Volkova
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Sol Gel ◽  
Rutile Phase ◽  
Photocatalytic Properties ◽  
Light Activation ◽  
X Ray ◽  
Tio2 Nanomaterials ◽  
Visible Light Activation ◽  
Thermal Stability Of

Sn-doped TiO2 nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20[Formula: see text]mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5[Formula: see text]mol.% of Sn.

scholarly journals Osseointegrating and phase-oriented micro-arc-oxidized titanium dioxide bone implants

2021 ◽  
Vol 19 ◽  
pp. 228080002110068
Author(s):  
Hsien-Te Chen ◽  
Hsin-I Lin ◽  
Chi-Jen Chung ◽  
Chih-Hsin Tang ◽  
Ju-Liang He
Keyword(s):  
Titanium Dioxide ◽  
High Surface ◽  
Cell Activity ◽  
Active Surface ◽  
Rutile Phase ◽  
Hydroxyl Groups ◽  
Bone Implant ◽  
Implant System

Here, we present a bone implant system of phase-oriented titanium dioxide (TiO2) fabricated by the micro-arc oxidation method (MAO) on β-Ti to facilitate improved osseointegration. This (101) rutile-phase-dominant MAO TiO2 (R-TiO2) is biocompatible due to its high surface roughness, bone-mimetic structure, and preferential crystalline orientation. Furthermore, (101) R-TiO2 possesses active and abundant hydroxyl groups that play a significant role in enhancing hydroxyapatite formation and cell adhesion and promote cell activity leading to osseointegration. The implants had been elicited their favorable cellular behavior in vitro in the previous publications; in addition, they exhibit excellent shear strength and promote bone–implant contact, osteogenesis, and tissue formation in vivo. Hence, it can be concluded that this MAO R-TiO2 bone implant system provides a favorable active surface for efficient osseointegration and is suitable for clinical applications.

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