Preparation of Bi2Ti2O7/TiO2 nanocomposites and their photocatalytic performance under visible light irradiation

Yi, Junhui; Yuan, Xiaojie; Wang, Hongjuan; Yu, Hao; Peng, Feng

doi:10.1016/j.matdes.2015.07.119

Cited by 32 publications

(8 citation statements)

References 25 publications

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“…Bismuth titanate with a pyrochlore-type structure (BTO), Bi 2 Ti 2 O 7 , is one of the promising photoactive compounds in the visible light range, which was predicted during first-principles calculations. ,− The experimental preparation of BTO in the nanoscale state was presented in papers recently. ,− The authors determined the optical band gap of Bi 2 Ti 2 O 7 to be within the range 2.58–3.28 eV. The observed scatter might be caused by different methods of sample synthesis, which affects the size and morphology of particles, and the different techniques of spectroscopic measurement.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

et al. 2020

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The photocatalytic properties of Bi2–x Ti2O7–1.5x (x = 0, 0.5) pyrochlores are examined via ab initio calculations and experiments. A coprecipitation method is applied for the synthesis of nanopowder pyrochlores. The pyrochlore phase formation starts at 500 °C (Bi2Ti2O7) and 550 °C (Bi1.5Ti2O6.25). Nanopowders are found to be a metastable character of pyrochlore phases. The presence of bismuth and oxygen vacancies enhances the thermal stability of the Bi1.5Ti2O6.25 phase in comparison with the Bi2Ti2O7 phase. The estimated crystallite size is 30–40 nm with noticeable agglomerates of about 100–300 nm according to scanning electron microscopy (SEM) and with the formation of particles (510–580 nm) in the aqueous medium. The isoelectric points of the nanopowders seem to be shifted to the strongly acidic region, resulting in the formation of negative surface particle charges of −33 mV (Bi2Ti2O7) and −27 mV (Bi1.5Ti2O6.25) at pH 5.88 in distilled water. The specific surface area is 11.5 m2/g (Bi2Ti2O7) and 12.00 m2/g (Bi1.5Ti2O6.25). The use of the generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional allows achieving an excellent agreement between theoretical and experimental structural parameters. The screened Coulomb hybrid HSE03 functional is the most appropriate for describing the optoelectronic properties. Bismuth titanate pyrochlores are wide-gap semiconductors with strong abilities to be active photocatalysts under visible irradiation. The optical E g values for direct/indirect transition according to the experiment, 3.19/2.94 eV (x = 0) and 3.24/3.03 eV (x = 0.5), and the DFT/HSE03 calculations, 2.92/2.87 (x = 0) and 3.42/– eV (x = 0.5), are in the visible light region and are close. The calculated low effective masses of the charge carriers and suitable band edge positions confirm the ability of the pyrochlores to act as photocatalysts. The photocatalytic activity has been evaluated through the decomposition of rhodamine B under visible irradiation. Bi2Ti2O7 shows the highest activity in comparison with Bi1.5Ti2O6.25, which is in good agreement with theoretically predicted and experimentally revealed characteristics.

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Section: Introductionmentioning

confidence: 99%

Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

et al. 2020

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“…When chemically pure, titania must be exposed to ultraviolet (UV) radiation to become photo-active. Various treatments, such as an organic dye attachment, hydrogen plasma reduction, and extrinsic chemical doping [11,12], have been investigated to reduce the band gap of titania in order to achieve photocatalytic activity under visible light (1.77-3.10 eV).…”

Section: Introductionmentioning

confidence: 99%

Effect of calcination on band gaps for electrospun titania nanofibers heated in air–argon mixtures

2016

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The relationship between the band gap in electrospun titania nanofibers at ambient temperature and the nature of the air-argon atmosphere in which the material has been heated nonisothermally to 900 °C was investigated by ultraviolet-visible absorption spectrometry at room temperature. The results for heating in different selected air-argon mixtures show that the UVregion band gap found in unheated as-spun amorphous nanofibers, 3.33 eV, may be shifted well into the visible region by calcining in the different air-argon mixtures. The band gap value found for heating in air, 3.09 eV, reduces systematically when the material is heated in an airargon mixture, with the gap in pure argon being 2.18 eV. The progressive lowering of the band gap is attributed to the development of crystallinity in the fibers as the material is calcined and the associated development of oxygen vacancies when heated in argon, and therefore to the formation of defect states below the conduction band.

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“…32-0118). The highest diffraction peak located at 2θ value of 30°, which can be indexed to the (444) plane [28,29]. The pattern of synthesized BiVO 4 /Bi 2 …”

Section: Crystal Structuresmentioning

confidence: 98%

“…The HRTEM image Fig.4a (HRTEM figure of BiVO 4 /Bi 2 Ti 2 O 7 ) clearly shows that the flower-like BiVO 4 possesses fine crystallinity and well agrees with the size and shape of BiVO 4 observed by SEM figures. One of lattice spacing was calculated to be 0.312 nm, corresponding to the (121) planes of monoclinic BiVO 4[26][27], and another lattice spacing was calculated to be 0.298 nm, corresponding to the (444) planes of Bi 2 Ti 2 O 7[28][29].…”

mentioning

confidence: 99%

Hydrothermal synthesis of novel flower-like BiVO 4 /Bi 2 Ti 2 O 7 with superior photocatalytic activity toward tetracycline removal

Han

Guo

et al. 2016

Applied Catalysis A: General

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Preparation of Bi2Ti2O7/TiO2 nanocomposites and their photocatalytic performance under visible light irradiation

Cited by 32 publications

References 25 publications

Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

Effect of calcination on band gaps for electrospun titania nanofibers heated in air–argon mixtures

Hydrothermal synthesis of novel flower-like BiVO 4 /Bi 2 Ti 2 O 7 with superior photocatalytic activity toward tetracycline removal

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Preparation of Bi2Ti2O7/TiO2 nanocomposites and their photocatalytic performance under visible light irradiation

Cited by 32 publications

References 25 publications

Photocatalytic Properties of Bi2–xTi2O7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

Photocatalytic Properties of Bi2–xTi2O7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

Effect of calcination on band gaps for electrospun titania nanofibers heated in air–argon mixtures

Hydrothermal synthesis of novel flower-like BiVO 4 /Bi 2 Ti 2 O 7 with superior photocatalytic activity toward tetracycline removal

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Product

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Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study

Photocatalytic Properties of Bi_2–xTi₂O_7–1.5x (x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study