Photodegradation of 2,4-dichlorophenoxyacetic acid over TiO2(B)/anatase nanobelts and Au-TiO2(B)/anatase nanobelts

[Display omitted] •Nanobelts are obtained via hydrothermal method with different starting materials.•The effect of calcination temperature and gold deposition has been studied.•TiO2 starting material plays an essential role in the phase transformation.•Optimum photocatalysts were obtained by calcina...

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Published in:	Applied surface science Vol. 467-468; pp. 1076 - 1087
Main Authors:	Chenchana, A., Nemamcha, A., Moumeni, H., Doña Rodríguez, J.M., Araña, J., Navío, J.A., González Díaz, O., Pulido Melián, E.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 15-02-2019
Subjects:	Au-TiO2 (TiO2(B)/anatase) nanobelts Heterogeneous photocatalysis Hydrothermal Sol-gel process Au-TiO2 (TiO2(B)/anatase) nanobelts Hydrothermal Sol-gel process Heterogeneous photocatalysis
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Summary:	[Display omitted] •Nanobelts are obtained via hydrothermal method with different starting materials.•The effect of calcination temperature and gold deposition has been studied.•TiO2 starting material plays an essential role in the phase transformation.•Optimum photocatalysts were obtained by calcination at 600 °C.•Au-TiO2 (TiO2(B)/anatase) showed high efficiency in photodegradation of 2,4-D. In this work, novel TiO2-based nanobelts with various phases were synthesized: biphasic TiO2(B)/anatase, pure TiO2(B) and pure anatase. These catalysts were obtained via hydrothermal reaction using two nanoparticulated TiO2 photocatalysts as precursors: Aeroxide TiO2 P25 (P25) and TiO2 synthesized via a sol-gel process (SG). In addition, the surface of the photocatalysts was modified with gold using a photodeposition method. A characterization study of the different photocatalysts was performed with X-ray diffraction analysis (XRD), UV–Vis diffuse reflectance spectra (DRS), scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS) and Brunauer-Emmett-Teller measurements (BET). The photocatalytic reaction of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated under UVA irradiation. A toxicity analysis was performed with the marine bioluminescent bacteria Vibrio fischeri. The highest 2,4-D removal efficiency of 99.2% was obtained with the biphasic Au-TiO2(TiO2(B)/anatase) nanobelts with anatase as predominant phase. Toxicity was mainly due to the intermediate 2,4-dichlorophenol (2,4-DCP) which was eliminated in 4 h. The TiO2 nanobelt phase structure is shown to have a significant effect on photocatalytic activity.
ISSN:	0169-4332 1873-5584
DOI:	10.1016/j.apsusc.2018.10.175