PHOTOCATALYTIC PROPERTIES OF TiO2/CNTs FILMS WITH DIFFERENT MORPHOLOGY ON STAINLESS STEEL SUBSTRATES

NANO ◽  
2014 ◽  
Vol 09 (01) ◽  
pp. 1450003 ◽  
Author(s):  
S. G. WANG ◽  
Z. R. DU ◽  
C. X. KONG ◽  
P. F. LI ◽  
J. L. XU ◽  
...  

CNTs– TiO 2 films with different morphology were fabricated on stainless steel substrates through chemical vapor hydrolysis deposition (CVHD) process and sol–gel process, respectively. Their morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic properties of the films were tested in the degradation of methyl orange by UV light irradiation. The results revealed that TiO 2 nanoparticles could form a continuous layer on the surface of CNTs through CVHD process. While for sol–gel process, most TiO 2 nanoparticles were isolated and only a small amount of TiO 2 nanoparticles attached on the surface of CNTs. And the photocatalytic property of TiO 2/CNTs film synthesized through CVHD process was better than that of TiO 2/CNTs films synthesized through sol–gel process. Electrochemical impedance spectroscopy (EIS) analysis illuminated that TiO 2/CNTs synthesized through CVHD process displayed a smaller resistance than the sample which was synthesized through sol–gel process and certified that the close combination between TiO 2 and CNTs could minimize recombination of photogenerated electrons and holes, and thus promote the photocatalytic property.

2008 ◽  
Vol 368-372 ◽  
pp. 1838-1840
Author(s):  
Jian Xiong Ye ◽  
Xin Gang Yu ◽  
Wen Yue Bi ◽  
De Jun Li ◽  
Hong Wen Ma ◽  
...  

ZrO2-CeO2 thin film was successfully prepared on 316L stainless steel by sol-gel process and the corrosion characteristics of the substrate coated with ZrO2-CeO2 thin film were evaluated through potentiodynamic polarization curve obtained in deaerated 15% H2SO4. The results show that, with the increase of CeO2 content, the corrosion rate of 316L stainless steel substrates coated with ZrO2-CeO2 thin film decreases. The surface morphology of the coating was observed by field scanning electron microscopy and the elements in the surface of coated substrate analyzed by FEM-EDX.


2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 988
Author(s):  
Lidija Ćurković ◽  
Helena Otmačić Ćurković ◽  
Irena Žmak ◽  
Mihone Kerolli Mustafa ◽  
Ivana Gabelica

In this work, a single-layer TiO2–ZrO2 thin film is deposited on the AISI 316L austenitic stainless steel by the sol–gel process and the dip coating method to improve its corrosion resistance properties. For the sol preparation, titanium isopropoxide and zirconium butoxide are used as the precursors, yttrium acetate hydrate is used for the ZrO2 stabilization, i-propanol as the solvent, nitric acid as the catalyst, acetylacetone as the chelating agent, and the distilled water for the hydrolysis. The deposited films are annealed at 400 °C or 600 °C. Morphology and phase composition of the sol–gel TiO2–ZrO2 films and powders are analyzed by scanning electron microscopy (SEM) equipped with EDX detector and X-ray diffraction (XRD), respectively. The thickness of the sol–gel TiO2–ZrO2 films deposited on the stainless steel is determined by glow discharge optical emission spectrometry (GD-OES). The corrosion behavior of the stainless steel, coated by amorphous films, is evaluated in 3 wt% NaCl and 0.5 mol dm−3 HCl by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the sol–gel TiO2–ZrO2 films with the amorphous structure, deposited by the sol–gel process, and calcined at 400 °C significantly enhance the corrosion properties of AISI 316L in both chloride media.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Junyang Li ◽  
Libo Gao ◽  
Qiang Zhang ◽  
Ruiting Feng ◽  
Hongyan Xu ◽  
...  

This study examined the different properties of Fe3O4/SiO2/TiO2(FST) core-shell nanoparticles encapsulated for one to five different times, represented as FST1 to FST5, respectively. These FST nanoparticles were obtained using the carbon reduction and sol-gel methods, and their properties were characterized by various tools, such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibratory sample magnetometer, laser granularity apparatus, and specific surface area analyzer. The relationship between irradiation time and decoloration ratio indicates that FST2 demonstrated significant efficiency in the decolorization of methyl orange (MO) under UV light. Further study on recycle activity showed that FST2 had a high decoloration rate after four cycles of photocatalysis, and its degradation of MO was well aligned with the apparent first-order kinetic equation. Furthermore, FST2 exhibited the highest apparent rate in the first cycle. All these results demonstrate that the recoverable FST2 possessed excellent photocatalytic activity while maintaining outstanding stability for further applications, such as managing environmental pollution.


2005 ◽  
Vol 486-487 ◽  
pp. 65-68 ◽  
Author(s):  
Sang Wook Lee ◽  
Hyun Suk Jung ◽  
Dong Wook Kim ◽  
Kug Sun Hong

5, 10, and 30 nm thickness of transparent TiO2 thin films were fabricated using sol-gel process, and the influence of film thickness on the photocatalytic property was investigated. The increase in film thickness was found to enhance the photocatalytic property of the films. Photocatalytic properties of each film were estimated by decomposition of stearic acid. The amount of decomposed stearic acid increased with film thickness (5 - 30 nm). For the case of 30 nm thickness film, the stearic acid was decomposed perfectly in twelve minutes. UV-vis spectra and photocurrents of each film clearly showed that the photoactivities of TiO2 films were related to the amount of absorbed UV light and band gap shift.


Author(s):  
L A Uscanga-González ◽  
E A Elvira-Hernández ◽  
R Pérez-Cuapio ◽  
A Pacio ◽  
F López-Huerta ◽  
...  

2009 ◽  
Vol 620-622 ◽  
pp. 679-682 ◽  
Author(s):  
Dae Yong Shin ◽  
Kyung Nam Kim

Thin films of various composition in the system of TiO2•SiO2 have been fabricated by the sol-gel process using Si(OC2H5) and Ti(OC3H7i)4 as precursors. TiO2•SiO2 films were formed on the glass substrate by spin-coating technique and heated at 500°C for 1 h. The relationship between hydrophilicity, photocatalytic properties and self-cleaning property with SiO2 addition and UV light irradiation were investigated. Photocatalytic activity of TiO2•SiO2 films showed decomposition of ~97% of acetaldehyde in 2 h and a water contact angle of ~10°. TiO2•SiO2 films can have more hydrophilic activity and less photocatalytic activity by increasing of SiO2 addition. XPS measurements revealed that the amount of organic compounds adsorbed on the films decreased with the UV light irradiation and SiO2 addition, because of the increased of both OH group contents in films and decomposed organic contaminants of the films surface.


Author(s):  
Atef Y. Shenouda ◽  
M. M. S. Sanad

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 135
Author(s):  
Kathleen Jaffré ◽  
Benoît Ter-Ovanessian ◽  
Hiroshi Abe ◽  
Nicolas Mary ◽  
Bernard Normand ◽  
...  

The effect of dry grinding on 304L stainless steel’s passive behavior is compared to two other surface finishing (mechanical polishing down to 2400 with SiC emery paper and 1 µm with diamond paste, respectively). The characterization of the surface state was performed using scanning electron microscopy, transmission electron microscopy, 3D optical profilometer, and X-ray diffraction. Results indicate that each surface treatment leads to different surface states. The ground specimens present an ultrafine grain layer and a strong plastic deformation underneath the surface, while an ultrafine grain layer characterizes the subsurface of the polished specimens. Grinding induces high residual compressive stresses and high roughness compared to polishing. The characterization of the passive films was performed by electrochemical impedance spectroscopy and Mott–Schottky analysis. The study shows that the semiconductor properties and the thickness of the passive films are dependent on the surface state of the 304L stainless steel.


2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.


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