Crystal structure and photocatalytic properties of titanate nanotubes prepared by chemical processing and subsequent annealing

Ali, Saima; Granbohm, Henrika; Ge, Yanling; Singh, Vivek Kumar; Nilsén, Frans; Hannula, Simo Pekka

doi:10.1007/s10853-016-0014-5

Cited by 25 publications

(17 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No hydroxyl vibrations are observed for the reference anatase powder. The decrease in hydroxyl groups with annealing is similar to previous results [ 3 , 11 ]. It should be noticed that the vibrations from 2000 to 2500 cm − 1 are due to an artifact from the equipment.…”

Section: Resultssupporting

confidence: 91%

“…TNT 450 and TNT 550 have a bandgap energy of 3.14 and 2.88 eV. A similar redshift towards visible light has also been observed for titanate nanotubes upon annealing [ 3 ]. This shift towards the visible light range is attributed to the change in the crystal structure of the nanotubes upon annealing, as rutile phase was observed at 550 °C in addition to anatase phase [ 11 ].…”

Section: Resultssupporting

confidence: 61%

“…TNTs have a high specific surface area and are either amorphous or crystalline structure depending on the synthesis process. The crystal structure can be modified by annealing with simultaneously affecting the morphology, bandgap, composition, and specific surface area of the nanotubes [ 3 , 11 ]. The bandgap of the TNTs is reported to be in the range of 3.0–3.2 eV [ 2 ] depending on the crystal structure of the nanotubes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Titania nanotubes prepared by rapid breakdown anodization for photocatalytic decolorization of organic dyes under UV and natural solar light

et al. 2018

Self Cite

View full text Add to dashboard Cite

Titania nanotube (TNT) powder was prepared by rapid breakdown anodization (RBA) in a perchloric acid electrolyte. The photocatalytic efficiency of the as-prepared and powders annealed at temperatures between 250 and 550 °C was tested under UV and natural sunlight irradiation by decolorization of both anionic and cationic organic dyes, i.e., methyl orange (MO) and rhodamine B (RhB), as model pollutants. The tubular structure of the nanotubes was retained up to 250 °C, while at 350 °C and above, the nanotubes transformed into nanorods and nanoparticles. Depending on the annealing temperature, the TNTs consist of anatase, mixed anatase/brookite, or anatase/rutile phases. The bandgap of the as-prepared nanotubes is 3.04 eV, and it shifts towards the visible light region upon annealing. The X-ray photoelectron spectroscopy (XPS) results show the presence of titania and impurities including chlorine on the surface of the TNTs. The atomic ratio of Ti/O remains unchanged for the annealed TNTs, but the concentration of chlorine decreases with temperature. The photoluminescence (PL) indicate high electron-hole recombination for the as-prepared TNTs, probably due to the residual impurities, low crystallinity, and vacancies in the structure, while the highest photocurrent was observed for the TNT sample annealed at 450 °C. The TNTs induce a small degradation of the dyes under UV light; however, contrary to previous reports, complete decolorization of dyes is observed under sunlight. All TNT samples showed higher decolorization rates under sunlight irradiation than under UV light. The highest reaction rate for the TNT samples was obtained for the as-prepared TNT powder sample under sunlight using RhB (κ1 = 1.29 h−1). This is attributed to the bandgap, specific surface area and the crystal structure of the nanotubes. The as-prepared TNTs performed most efficiently for decolorization of RhB and outperformed the reference anatase powder under sunlight irradiation. This could be attributed to the abundance of reactive sites, higher specific surface area, and degradation mechanism of RhB. These RBA TNT photocatalyst powders demonstrate a more efficient use of the sunlight spectrum, making them viable for environmental remediation.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2591-5) contains supplementary material, which is available to authorized users.

show abstract

Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Titania nanotubes prepared by rapid breakdown anodization for photocatalytic decolorization of organic dyes under UV and natural solar light

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Titania nanotubes—1D nanostructures with a high specific surface area—have been designed for a number of potential applications [ 39 ]. Titania nanotubes can be synthesized by various methods including hydrothermal [ 40 ] and electrochemical anodization [ 39 , 40 ], chemical processing [ 41 ], rapid breakdown anodization (RBA) [ 42 ], and template-assisted and electrospinning methods [ 40 ]. Thermal conductivity in the range of 0.40–0.84 W m −1 K −1 [ 1 ] and 0.55–0.75 W m −1 K −1 [ 33 ] have been observed for titanate nanotubes synthesized by the hydrothermal process.…”

Section: Introductionmentioning

confidence: 99%

Effect of Morphology and Crystal Structure on the Thermal Conductivity of Titania Nanotubes

et al. 2018

Self Cite

View full text Add to dashboard Cite

Titania nanotubes (TNTs) with different morphology and crystal structure are prepared by chemical processing and rapid breakdown anodization (RBA) methods. The nanotubes are studied in terms of thermal conductivity. The TNTs with variable wall thickness below 30 nm have significantly reduced thermal conductivity than bulk titania, due to the phonon confinement, smaller phonon mean free path, and enhanced phonon boundary scattering. The amorphous nanotubes (TNTAmor) have comparatively thicker walls than both crystalline nanotubes. The TNTAmor has a thermal conductivity of 0.98 W m−1 K−1, which is slightly less than the thermal conductivity of crystalline anatase nanotubes (TNTA; 1.07 W m−1 K−1). However, the titania nanotubes with mixed structure (TNTA,T) and the smallest dimensions have the lowest thermal conductivity of 0.75 W m−1 K−1, probably due to the phonon confinement. The experimental results are compared with the theoretical study considering the size confinement effect with different wall dimensions of TNTs and surface scattering. The results agree well with the surface roughness factor (p) of 0.26 for TNTA,T, 0.18 for TNTA, and 0.65 for TNTAmor, indicating diffusive phonon scattering and rougher surfaces for TNTA. Interestingly, the present results together with those presented in literature suggest that thermal conductivity reduction with respect to the wall thickness occurs also for the amorphous nanotubes. This is ascribed to the role of propagons in the thermal transport of disordered structures.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2613-3) contains supplementary material, which is available to authorized users.

show abstract

“…Great efforts have been devoted to improving the photocatalytic efficiency of semiconductor photocatalysts, which strongly depends on their morphologies and surface structures [2][3][4]. Strontium titanate (SrTiO 3 ), as a well-known cubic-perovskite-type multimetal oxide with a band gap of 3.2 eV comparing to TiO 2 , has been regarded as one of the most promising photocatalysts for water splitting and photodegradation of organic pollutants due to its superior catalytic activity, high chemical and photochemical stability, and good biological compatibility [2,5].…”

Section: Introductionmentioning

confidence: 99%

Low temperature hydrothermal synthesis of SrTiO3 nanoparticles without alkali and their effective photocatalytic activity

Shen¹,

Lu²,

Wang³

et al. 2016

J Adv Ceram

View full text Add to dashboard Cite

SrTiO 3 nanoparticle (NP) photocatalyst was synthesized with a facile and environmentalfriendly hydrothermal method using tetrabutyltitanate, strontium oxide, and ethanolamine as precursors at low temperature without alkali as mineralizer for the first time. The SrTiO 3 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and N 2 Brunauer-Emmett-Teller (BET) method. The SrTiO 3 catalyst synthesized at 120 ℃ (STO-120) exhibited the highest photocurrent intensity among the samples synthesized at different hydrothermal temperatures. The high photocatalytic performance of STO-120 was mainly attributed to the more homogeneous and minimum nanoparticle size, the highest surface area, and the maximum light absorption property among the four different samples. This work presented an applicable and facile method to fabricate a highly active and stable SrTiO 3 photocatalyst for organic pollutant degradation.

show abstract

Crystal structure and photocatalytic properties of titanate nanotubes prepared by chemical processing and subsequent annealing

Cited by 25 publications

References 70 publications

Titania nanotubes prepared by rapid breakdown anodization for photocatalytic decolorization of organic dyes under UV and natural solar light

Titania nanotubes prepared by rapid breakdown anodization for photocatalytic decolorization of organic dyes under UV and natural solar light

Effect of Morphology and Crystal Structure on the Thermal Conductivity of Titania Nanotubes

Low temperature hydrothermal synthesis of SrTiO3 nanoparticles without alkali and their effective photocatalytic activity

Contact Info

Product

Resources

About