HIERARCHICAL HETEROSTRUCTURE OF RUTILE TiO2 NANOFLOWER ARRAY ON ANATASE TiO2 SHEET WITH ENHANCED PHOTOCATALYTIC PERFORMANCE

2019 ◽  
Vol 26 (08) ◽  
pp. 1950040 ◽  
Author(s):  
MIN LAI ◽  
HAIBO YONG ◽  
KUN ZHONG ◽  
WEI WANG ◽  
JIALEI HUANG ◽  
...  

Hierarchical heterostructure of rutile TiO2 nanoflower array on anatase TiO2 sheet was fabricated by a two-step method. Anatase TiO2 sheet was synthesized by a modified dip coating method, followed by the formation of rutile TiO2 nanoflower array via a wet chemical route. Studies by X-ray diffraction and scanning electron microscopy indicated the formation of hierarchical heterostructure. Tests on degradation of methylene blue under UV light illumination showed that the hierarchical TiO2 film exhibited superior photocatalytic performance to those with monophased anatase and rutile TiO2 films and commercial P25 film. It was attributed to efficient separation of photogenerated charge carriers and prevention of the unfavorable multiple electron transfer on biphase interface. Investigation on the influence of addition of scavengers on photocatalysis suggested that hydroxy radicals and superoxide anion radicals dominated the photocatalytic degradation of MB. The hierarchical TiO2 film exhibited excellent photocatalytic stability in cycling tests.

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1188
Author(s):  
Seong-Rak Eun ◽  
Shielah Mavengere ◽  
Bumrae Cho ◽  
Jung-Sik Kim

Sol–gel synthesized N-doped and carbon–nitrogen–sulfur (CNS)-doped TiO2 solutions were deposited on upconversion phosphor using a dip coating method. Scanning electron microscopy (SEM) imaging showed that there was a change in the morphology of TiO2 coated on NaYF4:Yb,Er from spherical to nanorods caused by additional urea and thiourea doping reagents. Fourier transform infrared (FTIR) spectroscopy further verified the existence of nitrate–hyponitrite, carboxylate, and SO42− because of the doping effect. NaYF4:Yb,Er composites coated with N- and CNS-doped TiO2 exhibited a slight shift of UV-Vis spectra towards the visible light region. Photodecomposition of methylene blue (MB) was evaluated under 254 nm germicidal lamps and a 300 W Xe lamp with UV/Vis cut off filters. The photodegradation of toluene was evaluated on TiO2/NaYF4:Yb,Er and CNS-doped TiO2/NaYF4:Yb,Er samples under UV light illumination. The photocatalytic reactivity with CNS-doped TiO2/NaYF4:Yb,Er surpassed that of the undoped TiO2/NaYF4:Yb,Er for the MB solution and toluene. Photocatalytic activity is increased by CNS doping of TiO2, which improves light sensitization as a result of band gap narrowing due to impurity sites.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
V. L. Chandraboss ◽  
B. Karthikeyan ◽  
J. Kamalakkannan ◽  
S. Prabha ◽  
S. Senthilvelan

The TiO2/SiO2 and ZnO/SiO2 composite films were prepared by sol-gel dip coating method. The surface morphology and crystal structure of thin films were characterized by means of scanning electron microscopy (SEM) with elementary dispersive X-ray analysis (EDX) and X-ray diffractometer (XRD). Optical properties of films have been investigated using ultraviolet and visible spectroscopy (UV-visible spectroscopy). The photocatalytic activity was established by testing the degradation and decolorization of methyl green (MG) from aqueous solution with artificial UV-light.


2007 ◽  
Vol 336-338 ◽  
pp. 2203-2206 ◽  
Author(s):  
Hong Yi Li ◽  
Yun Han Ling ◽  
Bo Jiang ◽  
Wu Feng Jiang ◽  
Zhi Hong Guo ◽  
...  

TiO2 is one kind of semiconductor-based photocatalyst. TiO2 shows relatively high reactivity and chemical stability under ultraviolet (UV) light. However TiO2 is a poor absorber of photons in visible light. In order to improve the absorption efficiency, the coatings of TiO2/WO3, WO3 and TiO2 on ITO were prepared by liquid phase deposition (LPD) and dip coating method, their microstructure, surface properties, photoelectrochemical properties are investigated in this paper. XRD results showed that the phases on the composite coatings are mainly anatase, rutile and WO3 respectively, the SEM results showed that the coatings of TiO2 and TiO2/WO3 are distributed evenly on the materials surface. The electrochemical experiment results showed that open circuit potential of TiO2 and TiO2/WO3 with presence of the UV light illumination were about -343 mV and –650 mV respectively, comparatively the rest potential of 304 stainless steel is about 48 mV, which means that the TiO2 or TiO2/WO3 coatings can protect 304 stainless steel from corrosion, and TiO2/WO3 coatings retained for a while anticorrosion even absence of UV light.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Sadeghi ◽  
R. Sarraf-Mamoory ◽  
H. R. Shahverdi

LiMn2O4spinel cathode materials have been successfully synthesized by solid-state reaction. Surface of these particles was modified by nanostructured LiFePO4via sol gel dip coating method. Synthesized products were characterized by thermally analyzed thermogravimetric and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The results of electrochemical tests showed that the charge/discharge capacities improved and charge retention of battery enhanced. This improved electrochemical performance is caused by LiFePO4phosphate layer on surfaces of LiMn2O4cathode particles.


2013 ◽  
Vol 16 (1) ◽  
pp. 92-100
Author(s):  
Chien Mau Dang ◽  
Dam Duy Le ◽  
Tam Thi Thanh Nguyen ◽  
Dung Thi My Dang

In this study, we have successfully synthesized Fe3+ doped SiO2/TiO2 thin films on glass substrates using the sol-gel dip-coating method. After synthesizing, the samples were annealed at 5000C in the air for 1 hour. The characteristics and optical properties of Fe3+ doped SiO2/TiO2 films were then investigated by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FT-IR). An antifogging ability of the glass substrates coated with the fabricated film is investigated and explained by a water contact angle under visible-light. The analyzed results also show that the crystalline phase of TiO2 thin films comprised only the anatase TiO2, but the crystalline size decreased from 8.8 to 5.9 nm. We also observed that the absorption edge of Fe3+- doped SiO2/TiO2 thin films shifted towards longer wavelengths (i.e. red shifted) from 371.7nm to 409.2 nm when the Fe3+-doped concentration increased from 0 to 1 % mol.


2012 ◽  
Author(s):  
Wan Azelee Wan Abu Bakar ◽  
Mohd Yusof Othman ◽  
Noor Khaida Wati Mohd Saiyudi ◽  
Keiichi Tanaka

Pengoksidaanfoto benzena fasa gas menggunakan saput tipis TiO2 yang disinari lampu ultralembayung telah dikaji. Saput tipis ini disediakan melalui kaedah celup angkat menggunakan sol–gel TiO2. Tindak balas yang sama juga telah dijalankan menggunakan saput tipis TiO2 yang didop dengan Cu2+ dan Fe3+ dengan nisbah mol TiO2 terhadap ion logam 1:0.005, 1:0.001, 1:0.0005 dan 1:0.0003. Hasil kajian menunjukkan mangkin TiO2 dengan pancaran cahaya UV (354 nm) mendegradasikan gas benzena sebanyak 90% dalam masa 55 minit. Walau bagaimanapun penambahan ion Fe3+ dengan nisbah 1:0.0005 meningkatkan peratusan degradasi benzena kepada 98% dalam masa 55 minit, sebaliknya penambahan Cu2+memberikan kesan negatif kepada aktiviti foto TiO2. Kajian juga memperoleh satu nilai optimum dengan aktiviti pemangkinan adalah tertinggi bagi kedua-dua ion Fe3+ dan Cu2+. Pengaruh panjang gelombang cahaya ke atas aktiviti foto TiO2 juga telah dikaji dengan menggunakan mangkin TiO2 dop Fe3+ dengan nisbah optimum. Hasil kajian menunjukkan bahawa degradasi gas benzena meningkat dengan pengurangan tenaga cahaya yang dipancarkan. Kata kunci: Pemangkinanfoto; pengoksidaanfoto; saput tipis; TiO2 The gas phase photooxidation of benzene was investigated using TiO2 thin film irradiated with UV light source. The thin film was prepared via TiO2 sol gel dip coating method. The same reaction was also carried out using TiO2 doped with Cu2+ and Fe3+ with 1:0.005, 1:0.001, 1:0.0005 and 1:0.0003 mole ratios. The results showed that 90% of benzene was degraded after 55 minutes UV (354 nm) irradiation of the TiO2 thin film. However the addition of Fe3+ ions with 1:0.0005 mole ratio degraded 98% of benzene within 55 minutes. In contrast, Cu2+ ions however give a detrimental effect to the photoactivity of TiO2. An optimum ratio of dopant, where TiO2 showed the highest activity, was determined for both Fe3+ and Cu2+. The effect of different wave-length light source was also carried out using TiO2 doped Fe3+ with optimum ratio. The degradation of benzene was found to increase with decreasing light energy. Key words: Photocatalysis; photooxidation; TiO2 thin film


2013 ◽  
Vol 704 ◽  
pp. 275-280
Author(s):  
Janina Setina ◽  
Alona Gabrene ◽  
Inna Juhnevica ◽  
Gundars Mezinskis

The paper describes two methods of syntheses of iron oxides, microstructure and morphology of magnetite nanoparticles. Nanocomposite thin films of SiO2/Fe3O4 have been prepared with sol-gel dip coating technique: dip-coating from SiO2/Fe3O4 sol and encapsulation magnetite between two SiO2 layers. Structural and morphological characteristics of iron oxides particles and prepared film were analyzed by X-Ray Diffraction, SEM, FTIR, DTA, AFM. AFM topography of surface and measurements of roughness has shown that using iron oxide encapsulation between two SiO2 layers to provide the even distribution of iron oxide, results as high quality films with low Rq values 1.5 2.7 nm.


2007 ◽  
Vol 280-283 ◽  
pp. 819-822 ◽  
Author(s):  
Hong Yi Li ◽  
Yun Han Ling ◽  
Xing Jun Jiang ◽  
Xin De Bai

TiO2 is one kind of semiconductor-based photocatalyst. TiO2 shows relatively high reactivity and chemical stability under ultraviolet (UV) light. However TiO2 is poor absorber of photons in the solar spectrum. In order to improve the absorption efficiency, the coatings of TiO2/ZnFe2O4, ZnFe2O4and TiO2 on ITO were prepared by dip coating method, their microstructure, surface properties, photocurrent and photo absorption are investigated in this paper. XRD results show that the phases on the composite coatings are mainly TiO2 and ZnFe2O4 and the main phase on ZnFe2O4 and TiO2 coatings is ZnFe2O4 and TiO2 respectively, the SEM results show that the coatings of TiO2 and TiO2/ZnFe2O4 are distributed evenly on the materials surface and the AFM results show that the grain size is about 20nm. The experimental results also show that the absorption wavelength of composite coatings of TiO2/ZnFe2O4 is 454nm, which is larger than that of TiO2 coatings (370nm). Under the irradiation of Xe lamp light, a photocurrent of 27µA/cm2 on the materials surface could be obtained.


Author(s):  
Nur Fathirah Mohd Rahimi ◽  
Sathiabama T. Thirugnana ◽  
Sib Krishna Ghoshal ◽  
Rosnita Muhammad

In this study, the Yttrium Stabilized Zirconia (YSZ) thin films were deposited on the sapphire substrate (Al2O3) by dip-coating method using simple ethanol-based YSZ suspension. The layer thickness of YSZ films were varied by sintering at 1300°C. Phase change and structural evolution in YSZ films were observed by conducting X-ray diffraction (XRD) analyses. The microstructures and the surface morphology of the deposited films were examined using Atomic Force Microscope (AFM) and Field Emission Scanning Electron Microscope (FESEM). The XRD pattern revealed a phase change from cubic to monoclinic with an increase in YSZ layer thickness. The crystallite size was varied in the range of 9.68–42.98 nm with the changes in the layer thickness. Meanwhile, the AFM image analyses showed a layer thickness-dependent variation in the grain size (205.83–373.77 nm) and the RMS surface roughness (16.72–36.44 nm). The FESEM images of the achieved film exhibited the occurrence of a dense morphology. It was concluded that by controlling the layer thickness of the deposited films, their improved structure and morphology can be achieved.


2015 ◽  
Vol 31 ◽  
pp. 103-116 ◽  
Author(s):  
Chandra Risdian ◽  
Muhamad Nasir ◽  
Annisa Rahma ◽  
Heni Rachmawati

Electrospinning is a simple versatile process to produce nanofibers. However, it requires careful approach to form appropriates fibers for different purposes. This report describes aspects influencing successful development of nanofiber containing BSA using electrospinning method. Optical and scanning electron microscopy, energy dispersive X-Ray and Fourier transformed infrared spectroscopy, differential scanning calorimetric, and X-Ray diffraction analysis of nanofiber were performed. Modification of PVA/BSA nanofiber with Eudragit L-100 was conducted by dip coating method. The presence of BSA increased the diameter of the fibers. Modification of PVA/BSA nanofiber with Eudragit L-100 delayed the release of BSA in acidic medium but promoting its release in intestinal mimicking medium.


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