Correlating oxygen vacancies and phase ratio/interface with efficient photocatalytic activity in mixed phase TiO2

Verma, Ranjana; Samdarshi, S.K.

doi:10.1016/j.jallcom.2014.12.218

Cited by 62 publications

(41 citation statements)

References 44 publications

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“…7,22,46 There is a close correlation between the oxygen vacancies and the anatase to rutile phase ratio (A/R) in the mixed phase titania. 7 Accordingly, the quenching of the PL peaks may also be related to the A/R ratio. Thus, the lower A/R ratio shows higher reduction in recombination (given in Table 1).…”

Section: Methodsmentioning

confidence: 99%

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

2015

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The photocatalytic activity of the system critically depends on the catalyst's architecture and composition. In a ceria−titania system a proper ratio and location of ceria on titania might be crucial to have an optimum level of physicochemical properties for efficient charge carrier generation and separation in the system to initiate redox reaction at its surface. Herein, a novel architecture of the ceria-doped TiO 2 system has been developed to study its photoactivity and the mechanism of charge transfer. The photocatalytic activity with optimum cerium content Ce/Ti = 0.2 wt % shows the highest degradation of methylene blue under combined (UV + Vis) irradiation compared to the pristine titania. The obtained result shows that catalyst composition is an important parameter in modeling and optimizing the system to have the desired impact on photoactivity. The proposed unique architecture and composition combination appears to be an ideal model for design of novel photoactive materials having activity in a wide range of irradiation wavelength. The study is supported with characterization tools such as X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV−Vis absorption (UV−Vis, DRS), and fluorescence studies.

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Section: Methodsmentioning

confidence: 99%

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

2015

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“…These defects increase the width of the defects states forming continuous states. The presence of defects creates the band state which narrows the band gap, the magnitude of which depends on the defect density [37,38]. When light falls, photogenerated excited electron moves to conduction band leaving behind holes in valence band.…”

Section: Photocatalytic Activity Of Pristine and Mixed Phase Disordermentioning

confidence: 99%

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

Verma

Samdarshi

Sreedhar

et al. 2015

Solar Energy Materials and Solar Cells

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134

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“…CeO 2 , on the other hand, has been shown to be a promising candidate because of its desirable band edge positions and it has been successfully used in a number of photocatalytic processes, such as detoxification and hydrogen production. The redox shift between Ce 4+ and Ce 3+ can create a high capacity for the system to store or release oxygen under oxidizing or reducing conditions12131415. Many studies have reported that CeO 2 -TiO 2 systems have enhanced properties under UV solar irradiation.…”

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Photodegradation of organic pollutants RhB dye using UV simulated sunlight on ceria based TiO2 nanomaterials for antibacterial applications

Kaviyarasu

Kennedy

Manikandan

et al. 2016

Sci Rep

388

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To photo-catalytically degrade RhB dye using solar irradiation, CeO 2 doped TiO 2 nanocomposites were synthesized hydrothermally at 700 °C for 9 hrs. All emission spectra showed a prominent band centered at 442 nm that was attributed to oxygen related defects in the CeO 2 -TiO 2 nanocrystals. Two sharp absorption bands at 1418 cm −1 and 3323 cm −1 were attributed to the deformation and stretching vibration, and bending vibration of the OH group of water physisorbed to TiO 2 , respectively. The photocatalytic activities of Ce-TiO 2 nanocrystals were investigated through the degradation of RhB under UV and UV+ visible light over a period of 8 hrs. After 8 hrs, the most intense absorption peak at 579 nm disappeared under the highest photocatalytic activity and 99.89% of RhB degraded under solar irradiation. Visible light-activated TiO 2 could be prepared from metal-ion incorporation, reduction of TiO 2 , non-metal doping or sensitizing of TiO 2 using dyes. Studying the antibacterial activity of Ce-TiO 2 nanocrystals against E. coli revealed significant activity when 10 μg was used, suggesting that it can be used as an antibacterial agent. Its effectiveness is likely related to its strong oxidation activity and superhydrophilicity. This study also discusses the mechanism of heterogeneous photocatalysis in the presence of TiO 2 . Solar energy is uniquely poised to solve major energy and environmental challenges that are being faced by humankind. As such, it is important to develop a suitable environmentally-friendly technology that permits the full range of the solar spectrum to be used for simultaneously solving energy and environmental challenges. It has been proposed that it is possible to address these challenges using nanocomposite materials that are capable of solar photocatalytic conversion 1,2 . Nanocomposite materials have a mixture of different chemical compositions and have received wide interest from fundamental and applied science researchers. The physical properties of these materials can be combined to produce materials that have desirable characteristics. Optical or biological characteristics can change with decreasing particle sizes, which is a major reason for interest in nanocomposite materials 3 . For example, metal oxide nanocomposites have excellent physical properties, such as high hardness and melting points, low densities and coefficients of thermal expansion, high thermal conductivities, good chemical stabilities. They also have improved mechanical properties, such as higher specific strengths, better wear resistance and specific modulus, and have wide potential for various industrial fields 4,5 .

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Correlating oxygen vacancies and phase ratio/interface with efficient photocatalytic activity in mixed phase TiO2

Cited by 62 publications

References 44 publications

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

Photodegradation of organic pollutants RhB dye using UV simulated sunlight on ceria based TiO2 nanomaterials for antibacterial applications

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Correlating oxygen vacancies and phase ratio/interface with efficient photocatalytic activity in mixed phase TiO2

Cited by 62 publications

References 44 publications

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO2 Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO2 Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

Photodegradation of organic pollutants RhB dye using UV simulated sunlight on ceria based TiO2 nanomaterials for antibacterial applications

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Product

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Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation

Hexagonal Ceria Located at the Interface of Anatase/Rutile TiO₂ Superstructure Optimized for High Activity under Combined UV and Visible-Light Irradiation