Synthesis of Silver-Doped Titanium Dioxide Nanotubes by Single-Step Anodization for Enhanced Photodegradation of Acid Orange 52

2019 ◽  
Vol 950 ◽  
pp. 149-153
Author(s):  
Edgar Clyde R. Lopez ◽  
Joey D. Ocon ◽  
Jem Valerie D. Perez

Silver-doped TiO2 nanotubes (Ag-TiNTs) were synthesized in a top-down approach by single-step anodization of titanium sheets. The highly-ordered array of Ag-TiNTs was confirmed by scanning electron microscopy with an average inner diameter of 41.28 nm and a wall thickness of 35.38 nm. Infrared spectroscopy confirmed the presence of O-Ti-O bonds. Analysis of the X-ray powder diffraction profiles showed the characteristic peaks for anatase and titanium for both pristine TiNTs and Ag-TiNTs. Ag-doping caused no observed changes in the crystalline structure of pristine TiNTs. High-definition X-ray fluorescence spectroscopy revealed that the synthesized Ag-TiNTs have 0.05 wt% Ag-loading. Even at low Ag-loading, the Ag-TiNTs were shown to be photo-active, achieving 10.13% degradation of Acid Orange 52 under UV illumination after 120 min.

2019 ◽  
Vol 801 ◽  
pp. 285-291 ◽  
Author(s):  
Edgar Clyde R. Lopez ◽  
Vince Aron F. Cleofe ◽  
Rio Ysabel A. Cañal ◽  
Kristoffer Francis P. Boado ◽  
Jem Valerie D. Perez

Highly-organized one-dimensional arrays of copper-doped titanium dioxide nanotubes (Cu-TiNTs) were synthesized in a one-pot approach by double anodization of titanium sheets. Field-emission scanning electron microscopy showed that Cu-TiNTs have an average inner diameter of 52.13 nm, a wall thickness of 14.28 nm, and a tube length of 0.6401 μm. Fourier-transform infrared spectroscopy confirmed the presence of characteristic O-Ti-O bond of TiO2. X-ray fluorescence spectroscopy confirmed copper-doping with an average dopant loading of 0.0248%. Even at this low dopant loading, Cu-TiNTs were shown to be photo-active in degrading Acid Orange 52 (AO 52) under UV light illumination. The kinetic profiles of AO 52 photoelectrochemical degradation were best described by the pseudo-first-order kinetic model (R2 ≥ 0.991) with kinetic constants 9.42 x 10-3 min-1 for Cu-TiNTs as compared to 6.04 x 10-3 min-1 for pristine TiNTs. Overall, doping pristine TiNTs with Cu was shown to enhance its photoelectrocatalytic properties in degrading textile dyes such as AO 52.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 10
Author(s):  
Daria V. Mamonova ◽  
Anna A. Vasileva ◽  
Yuri V. Petrov ◽  
Denis V. Danilov ◽  
Ilya E. Kolesnikov ◽  
...  

Surfaces functionalized with metal nanoparticles (NPs) are of great interest due to their wide potential applications in sensing, biomedicine, nanophotonics, etc. However, the precisely controllable decoration with plasmonic nanoparticles requires sophisticated techniques that are often multistep and complex. Here, we present a laser-induced deposition (LID) approach allowing for single-step surface decoration with NPs of controllable composition, morphology, and spatial distribution. The formation of Ag, Pt, and mixed Ag-Pt nanoparticles on a substrate surface was successfully demonstrated as a result of the LID process from commercially available precursors. The deposited nanoparticles were characterized with SEM, TEM, EDX, X-ray diffraction, and UV-VIS absorption spectroscopy, which confirmed the formation of crystalline nanoparticles of Pt (3–5 nm) and Ag (ca. 100 nm) with plasmonic properties. The advantageous features of the LID process allow us to demonstrate the spatially selective deposition of plasmonic NPs in a laser interference pattern, and thereby, the formation of periodic arrays of Ag NPs forming diffraction grating


2012 ◽  
Vol 518-523 ◽  
pp. 775-779 ◽  
Author(s):  
Dong Dong Tan ◽  
De Fu Bi ◽  
Peng Hui Shi ◽  
Shi Hong Xu

The TiO2/NiFe2O4 (TN) composite nanoparticles with different mass ratios of NiFe2O4 to TiO2 were prepared via sol-gel method. X-ray diffraction was used to characterize the phase structure of TN. The results indicated that adulterating a smidgen of NiFe2O4 into the TiO2 (about 0.1%) can promote the phase transformation of TiO2, however, when the doping amount of NiFe2O4 surpasses 1%, the introduction of NiFe2O4 can inhibit the growth of TiO2 crystal grain and reduce the size of TiO2 crystal grain. The degradation experiment of methyl orange solution under UV illumination (253.7 nm) showed that the content of NiFe2O4 in the TN was higher, the photocatalytic activity of TN was worse, and the 0.1% TiO2/NiFe2O4 calcined at 400 °C presented the best photocatalytic activity.


1989 ◽  
Vol 62 (735) ◽  
pp. 201-208 ◽  
Author(s):  
J. C. Buckland-Wright
Keyword(s):  

1992 ◽  
Vol 10 (4) ◽  
pp. 861-863 ◽  
Author(s):  
R. Suchańska

Two methods of target technology for investigation of X-ray laser–plasma emission are presented. The first deals with steel and gold microcapillary targets. They are about 200 μm in inner diameter and about 500 μm in length. The second method deals with metal plus plastic targets of reduced and controlled density in the range of 1.6–8.1 g/cm3 for Cu + polyethylene (PE) and 1.6–7.6 g/cm3 for Fe + PE.


Author(s):  
Saranyoo Chaiwichian ◽  
Buagun Samran

Abstract Monoclinic BiVO4 photocatalyst films decorated on glass substrates were successfully fabricated via a dip-coating technique with different annealing temperatures of 400 °C, 450 °C, 500°C, and 550 °C. All of the physical and chemical properties of as-prepared BiVO4 photocatalyst film samples were investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectra techniques. The results revealed that the as-prepared BiVO4 photocatalyst film samples retained a monoclinic phase with an average particle size of about 50 – 100 nm. Moreover, the BiVO4 photocatalyst film samples showed a strong photoabsorption edge in the range of visible light with the band gap energy of 2.46 eV. The photocatalytic activities of all the film samples were tested by the degradation of model acid orange 7 under visible light irradiation. The BiVO4 photocatalyst film sample annealed at a temperature of 500 °C showed the highest photoactivity efficiency compared with other film samples, reaching up to 51%within 180 min. In addition, the stability and reusability of BiVO4 photocatalyst film sample made with an annealing temperature of 500 °C did not show loss of photodegradation efficiency of acid orange 7 after ten recycles. A likely mechanism of the photocatalytic process was established by trapping experiments, indicating that the hydroxyl radical scavenger species can be considered to play a key role for acid orange 7 degradation under visible light irradiation.


2015 ◽  
Vol 68 (8) ◽  
pp. 1293 ◽  
Author(s):  
Pakvipar Chaopanich ◽  
Punnama Siriphannon

Hydroxyapatite (HAp) nanoparticles were successfully synthesized from an aqueous mixture of Ca(NO3)2·4H2O and (NH4)2HPO4 by a facile single-step refluxing method using polystyrene sulfonate (PSS) as a template. The effects of reaction times, pH, and PSS concentration on the HAp formation were investigated. It was found that the crystalline HAp was obtained under all conditions after refluxing the precursors for 3 and 6 h. The longer refluxing time, the greater the crystallinity and the larger the crystallite size of the HAp nanoparticles. The HAp with poor crystallinity was obtained at pH 8.5; however, the well-crystallized HAp was obtained when reaction pH was increased to 9.5 and 10.5. In addition, the X-ray diffraction patterns revealed that the presence of PSS template caused the reduction of HAp crystallite size along the (002) plane from 52.6 nm of non-template HAp to 43.4 nm and 41.4 nm of HAp with 0.05 and 0.2 wt-% PSS template, respectively. Transmission electron microscopy images of the synthesized HAp revealed the rod-shaped crystals of all samples. The synthesized HAp nanoparticles were modified by l-aspartic acid (Asp) and l-arginine (Arg), having negative and positive charges, respectively. It was found that the zeta potential of HAp was significantly changed from +5.46 to –24.70 mV after modification with Asp, whereas it was +4.72 mV in the Arg-modified HAp. These results suggested that the negatively charged amino acid was preferentially adsorbed onto the synthesized HAp surface.


2009 ◽  
Vol 24 (1) ◽  
pp. 245-252 ◽  
Author(s):  
Robert Ianoş

Single-phase nanocrystalline 4CaO·Al2O3·Fe2O3 powders were prepared directly from the combustion reaction using a new cost-effective, time-saving, and environmentally friendly version of solution combustion synthesis. Instead of a single fuel, a fuel mixture of urea and β-alanine was used. It was shown by x-ray diffraction, energy-dispersive x-ray analysis, thermogravimetric analysis, and optical microscopy that this new version of the solution combustion synthesis allows the maximization of the exothermic effect associated with the combustion reaction. On the other hand, it was shown that the traditional version of combustion synthesis involving the use of a single fuel, such as urea or β-alanine, does not ensure the formation of Ca4Al2Fe2O10 unless subsequent thermal treatments are applied. It was suggested that the occurrence of combustion reactions cannot be regarded only in terms of adiabatic temperature, as the kinetic aspects overrule the thermodynamic ones.


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