Effects of Hydrothermal Crystallization on the Morphologies and Photocatalytic Activity of TiO2 Nanotubes

2013 ◽  
Vol 631-632 ◽  
pp. 504-510
Author(s):  
Su Qin Liu ◽  
Ying Liang

Anatase titania (TiO2) films with highly photocatalytic activity were prepared by hydrothermal treatment of amorphous TiO2 nanotubes (NTs) via electrochemical anodization of titanium (Ti) in fluorine-containing electrolyte. The as-prepared TiO2 films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The photocatalytic activity of the as-prepared TiO2 films was evaluated by the photocatalytic degradation of methyl orange (MO) aqueous under UV-light irradiation. The effects of hydrothermal temperature and time on the morphologies, microstructure and photocatalytic activity of TiO2 films were investigated and discussed. It was found that TiO2 NTs were converted to nanoparticles after hydrothermal treatment. The mechanism of deformation of TiO2 NTs was discussed. Hydrothermal treatment enhances the phase transformation of TiO2 films from amorphous to anatase and crystallization of anatase. An optimal hydrothermal condition (150 oC for 8 h) was determined. The anatase TiO2 films prepared under optimal hydrothermal conditions posses larger surface area and higher relative anatase crystallinity and its photocatalytic activity is higher than that of anatase TiO2 films prepared under other hydrothermal conditions.

2006 ◽  
Vol 6 (3) ◽  
pp. 762-770 ◽  
Author(s):  
Masanori Hirano ◽  
Kazumasa Matsushima

Anatase-type TiO2 nanoparticles doped with 0–30 mol% niobium were directly formed from precursor solutions of TiOSO4 and NbCl5 under mild hydrothermal conditions at 120–180 °C for 5 h using the hydrolysis of urea. When the niobium content increased from 0 to 30 mol%, the crystallite size of anatase increased from 8.5 to 19 nm. The band gap of anatase was slightly decreased by making solid solutions with niobium. Their photocatalytic activity and adsorptivity were evaluated separately by the measurement of the concentration of methylene blue (MB) remained in the solution after maintained in the dark or under UV-light irradiation. To form anatase-type solid solutions by doping 5–15 mol% niobium into TiO2 was effective for improvement of the photoactivity of TiO2. The photocatalytic activity (the photooxidation rate) and the adsorption amount of MB for the sample containing 15 mol% niobium became more than approximately nine times and six times as much as those of the hydrothermal anatase-type pure TiO2, respectively.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Mingjie Ma ◽  
Weijie Guo ◽  
Zhengpeng Yang ◽  
Shanxiu Huang ◽  
Guanyu Wang

TiO2/fine char (FC) photocatalyst was prepared via sol-gel method with tetrabutyl titanate as the precursor and FC as the carrier. The structural property of TiO2/FC photocatalyst was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the photocatalytic activity of TiO2/FC was evaluated by photocatalytic degradation of rhodamine B (RhB) aqueous solution under UV light irradiation. The results showed that TiO2was successfully coated on the surface of FC, and the TiO2/FC photocatalyst had better photocatalytic efficiency and stability for degradation of RhB under UV light illumination as compared to that of the pure TiO2and FC. The study provided a novel way for the application of FC to the photocatalytic degradation of organic wastes.


2015 ◽  
Vol 1087 ◽  
pp. 218-222
Author(s):  
Siti Aida Ibrahim ◽  
Srimala Sreekantan

Nanostructured Fe-TiO2 and TiO2 with anatase structure were synthesized via combination method of sol-gel and peptization process. The samples were characterized by X-ray diffraction (XRD), Transmission emission microscopy (TEM) and UV-Vis spectroscopy (UV-Vis). The presence of Fe3+ ion shifted the absorption profile of TiO2 to the longer wavelength side of the spectrum, indicating an obvious photocatalytic activity under visible irradiation. Photocatalytic activity of the samples were evaluated by methyl orange (MO) discolouration under UV-light irradiation. Compared with the pure TiO2 nanoparticles, the Fe-TiO2 nanoparticles exhibited higher photocatalytic activity with 95% discoloration within 2 h.


2013 ◽  
Vol 11 (11) ◽  
pp. 1780-1785 ◽  
Author(s):  
Maria Gancheva ◽  
Reni Iordanova ◽  
Yanko Dimitriev ◽  
Georgi Avdeev ◽  
Tzvetoslav Iliev

AbstractZinc oxide (ZnO) was mechanically activated in air using a planetary ball mill using varying milling speeds and time. The obtained samples were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and UV-Vis diffusion reflectance spectroscopy. The photocatalytic activity of the mechanically treated ZnO powders were investigated in the reaction of Malachite Green (MG) degradation in aqueous solution under UV-light irradiation. A decrease in the crystallite size (from 90 to 10 nm) accompanied by an increase of microstrains and lattice parameters were established applying different milling speeds. The agglomeration of the particles was observed by SEM analysis. The absorption spectra of the initial and mechanically activated ZnO samples show shifting of the band position from 360 to 330 nm, which can be related to decrease in the crystalline size. The ZnO powders activated at lower milling speeds (for shorter time intervals) exhibit highest photocatalytic activity.


2010 ◽  
Vol 148-149 ◽  
pp. 1204-1207
Author(s):  
Jing Hu ◽  
Ming Guo Ma ◽  
Jian Zhang Li

The Zn/Sn-composite oxide nanogranules were synthesized via a simple hydrothermal method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the hydrothermal temperature significantly influences the morphology, microstructure, and composition of the as-prepared samples. And the nano-sized ZnO/Zn2SnO4 exhibited high photocatalytic activities on the degradation of methyl orange (MO) under ultraviolet (UV) light irradiation.


2012 ◽  
Vol 178-181 ◽  
pp. 531-534
Author(s):  
Yan Lin Ye ◽  
Pei Song Tang

The YVO4 was synthesized by microwave assisted process. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), thermogravimetry and differential thermal analysis (TG-DTA) and Brunauer-Emmett-Teller (BET) method. The results show that YVO4 was tetragonal crystal, particle size of 50 to 80 nm, band gap of 3.3 eV and surface area of 18.6m2/g. The photocatalytic experiment of YVO4 shows the high photocatalytic activity for the decomposition of methyl orange under UV-light irradiation.


2017 ◽  
Vol 14 (4) ◽  
pp. 279-283 ◽  
Author(s):  
Juan Xie ◽  
Yongjing Hao ◽  
Meixia Li ◽  
Yiwei Lian ◽  
Li Bian

Purpose This paper aims to report a novel preparation method of titanium dioxide (TiO2)/zinc oxide (ZnO) composites with different mole ratios of TiO2:ZnO and their photocatalytic activity. Design/methodology/approach TiO2/ZnO composites are prepared by a facile route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultra-violet–visible diffuse reflectance spectra (UV-vis DRS) are used to characterize the products. Photocatalytic activity of the samples is evaluated by degradation of persistent organic pollutant pentachlorophenol under ultra-violet (UV) irradiation. Findings It is found that all the as-prepared TiO2/ZnO composites not only have good catalytic activity under UV light irradiation, but also have excellent circulation stability. The optimal mole ratio of TiO2:ZnO is 0.75:1. Originality/value This report presents a simple and rapid method for the preparation of TiO2/ZnO composites with excellent photocatalytic activity. Experimental results could provide useful reference for the treatment of chlorophenols in the future.


2020 ◽  
Vol 75 (8) ◽  
pp. 727-732
Author(s):  
Chen Zhang ◽  
Jian-Qing Tao

AbstractA new Cu(II) metal-organic framework, [Cu(L)(OBA)·H2O]n (1) [H2OBA = 4,4′-oxybis(benzoic acid), L = 3,5-di(1H-benzimidazol-1-yl)pyridine] was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis and single-crystal X-ray diffraction. Complex 1 is a four-connected uni-nodal 2D net with a (44·62) topology which shows an emission centered at λ ∼393 nm upon excitation at λ = 245 nm. Moreover, complex 1 possesses high photocatalytic activities for the decomposition of Rhodamine B (RhB) under UV light irradiation.


2015 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Nur Afifah ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh

In this study, the photocatalytic activity of pure Fe- doped ZnO and Fe- doped ZnO/Montmorillonite nanocomposite has been investigated for the degradation of malachite green under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, and electron spin resonance. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to pure Fe- doped ZnO. To detect the possible reactive species involved in degradation of organic dyes control experiments with introducing scavengers into the solution of organic dyes were carried out. It is found that electron plays an important role in the degradation of malachite green.


2013 ◽  
Vol 448-453 ◽  
pp. 169-173
Author(s):  
Chun Yan Yan ◽  
Wen Tao Yi

Pure and F, Fe-codoped TiO2 were prepared by sol-hydrothermal process, in which titanium (IV) n-butoxide, Fe (NO3)2·6H2O and NH4F were used as precursors. And the samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and N2 adsorption-desorption method. The results showed that the F, Fe-codoped samples were principally single-phase anatase structures, and the particles possessed higher BET area than that of pure TiO2. The photocatalytic activity and reusability of the catalysts under UV light (365nm) was investigated with neutral red as the model compound. The results showed that F (2.0%), Fe (4.0%) codoped TiO2 had the highest photocatalytic activity among all as-prepared samples. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood (L-H) pseudo first order reaction model.


Sign in / Sign up

Export Citation Format

Share Document