scholarly journals Preparation and electrochemical characterization of Pt nanoparticles dispersed on niobium oxide

2003 ◽  
Vol 28 (2) ◽  
pp. 69-76
Author(s):  
R. L. S. Mello ◽  
F. I. Mattos-Costa ◽  
H. de las M. Villullas ◽  
L. O. de S. Bulhões

Electrodes consisting of Pt nanoparticles dispersed on thin films of niobium oxide were prepared onto titanium substrates by a sol-gel method. The physical characterization of these electrodes was carried out by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The mean size of the Pt particles was found to be 10.7 nm. The general aspects of the electrochemical behavior were studied by cyclic voltammetry in 1 mol L-1 HClO4 aqueous solution. The response of these electrodes in relation to the oxidation of formaldehyde and methanol in acidic media was also studied.

1998 ◽  
Vol 519 ◽  
Author(s):  
E. Scolan ◽  
C. Sanchez

AbstractMonodisperse non-aggregated nanoparticles of titania are obtained through hydrolysis at 60°C of titanium butoxide in the presence of acetylacetone and para-toluene sulfonic acid. After drying the resulting xerosols can be dispersed without aggregation in water-alcoholic or alcoholic solutions. The characterizations of the nanoparticles have been carried out by using quasi-elastic light scattering (QELS), 13C 1H in solution and X-ray diffraction, TEM, TG-DTA, 13C CP-MAS NMR in the solid state. The mean size of the anatase oxide core can be adjusted in the I to 5 nanometer range by a careful tuning of the synthetic conditions. The anatase particles are surrounded by acetylacetonato ligands, para-toluene sulfonate based species and water.


1981 ◽  
Vol 50 (9) ◽  
pp. 3071-3074 ◽  
Author(s):  
Ken-ichi Ohshima ◽  
Shigeki Yatsuya ◽  
Jimpei Harada

2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.


2017 ◽  
Vol 31 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Mohammad Hossein Ghorbani ◽  
Abdol Mahmood Davarpanah

Manganese oxides are of more interest to researchers because of their ability as catalysts and lithium batteries. In this research, MnO2nanowires with diameter about 45 nm were synthesized by sol–gel method at room temperature (RT). Effect of increasing the annealing temperature from 400[Formula: see text]C to 600[Formula: see text]C on crystalline structure of nanostructure were studied and average crystallite size was estimated about 22 nm. X-ray Diffraction (XRD) method, Energy-Dispersive X-ray Diffraction (EDXD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) were used to characterize the nanowires of MnO2.


2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.


DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 278-287
Author(s):  
Javier Alberto Olarte Torres ◽  
María Cristina Cifuentes Arcila ◽  
Harvey Andrés Suárez Moreno

This paper presents the results obtained from the synthesis and morphological characterization of different magnetite samples:  La0.67-x Prx Ca0.33 MnO3.LaMn1-x Cox O3 and LaMn1-x Nix O3 at 0.13 ≤ 𝑥𝑥 ≤ 0.67 produced by a solid-state reaction mechanism and 𝐿𝐿𝐿𝐿𝑀𝑀𝑀𝑀1−𝑥𝑥(𝐶𝐶𝐶𝐶/𝑁𝑁𝑁𝑁)𝑥𝑥𝑂𝑂3 at 0.0 ≤ 𝑥𝑥 ≤ 0.5 produced by the sol-gel method. These samples were characterized using X-ray diffraction spectroscopy and by measuring electric resistivity and magnetic susceptibility which were carried out as a function of temperature. Notably, the effects of strain and compressive strength on the lattices of magnetite samples were highly dependent on the concentration of 𝑃𝑃𝑟𝑟, 𝐶𝐶𝐶𝐶, and 𝑁𝑁𝑁𝑁. Moreover, the transition temperatures of metal-insulator and ferromagnetic-paramagnetic phases also largely depend on these strength effects, e.g., at higher concentrations of 𝑃𝑃𝑟𝑟, effects of increased strain strength were observed, relocating the shifts of ferromagnetic-paramagnetic transitions to lower temperatures. On the other hand, effects of increased compressive strength were observed at higher concentrations of 𝑁𝑁𝑁𝑁 and 𝐶𝐶𝐶𝐶, relocating the shifts of ferromagnetic-paramagnetic and metal-insulator transitions to higher temperatures.


Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 601
Author(s):  
Yahua Hu ◽  
Mu Gu ◽  
Xiaolin Liu ◽  
Juannan Zhang ◽  
Shiming Huang ◽  
...  

Uniform Lu2O3:Eu3+ nanowire arrays were successfully prepared by the sol-gel process using anodic aluminum oxide (AAO) templates. The as-synthesized nanowires are homogeneous, highly ordered, and dense and have a uniform diameter of ~300 nm defined by the AAO templates. The X-ray diffraction and selected area electron diffraction results show that the Lu2O3:Eu3+ nanowires have a polycrystalline cubic structure, and the crystallite size of the Lu2O3:Eu3+ nanowires is confined by the AAO template. The nanowires within the AAO template showed good photoluminescence and X-ray-excited optical luminescence performances for Lu2O3:Eu3+. The emission peaks were attributed to the 5D0 → 7FJ transitions of Eu3+ (J = 0, 1, 2, 3).


2012 ◽  
Vol 626 ◽  
pp. 425-429 ◽  
Author(s):  
N.N. Hafizah ◽  
Mohamed Zahidi Musa ◽  
Mohamad Hafiz Mamat ◽  
M. Rusop

In this study, TiO2nanopowder was synthesized via a sol-gel grinding method. The effects of TiO2precursor concentration of TiO2nanopowder were investigated. The TiO2nanopowder obtained were characterized using X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) for their structural properties. From the calculation of the crystallite size in XRD, the size of the nanoparticles obtained is 49.55 nm at the highest TiO2precursor concentration. In contrast, at the lower concentration of 0.4 molar give the cryatallite size of 12.84 nm. Further, XRD and Raman spectrum results confirmed the TiO2nanopowder obtain composed of only anatase phase. The FESEM micrographs of TiO2nanopowder also were discussed in this paper.


2014 ◽  
Vol 997 ◽  
pp. 359-362 ◽  
Author(s):  
Chun Hong Ma ◽  
Xue Lin ◽  
Liang Wang ◽  
Yong Sheng Yan

Nanocrystalline bismuth titanate (Bi4Ti3O12; BTO) powders were successfully prepared by the sol-gel method, using bismuth nitrate (Bi(NO3)3·5H2O) and tetrabutyl titanate (Ti(OC4H9)4) as source materials, acetic anhydride and ethanediol as solvents. The thermal decomposition and phase inversion process of the gel precursors were studied by using differential thermal analysis (DTA). The crystal structures and microstructures of BTO powders were investigated by using x-ray diffraction (XRD), and transmission electron microscope (TEM). The crystallization of amorphous bismuth titanate has been discussed. The effect of sintering temperature on the structure and morphology of BTO was investigated. At 644 oC and above, BTO powder undergoes a phase transformation from tetragonal to orthorhombic. At 900 oC, the purified orthorhombic BTO nanocrystals were obtained.


2006 ◽  
Vol 510-511 ◽  
pp. 710-713
Author(s):  
Hwan Tae Kim ◽  
Won Sik Seo ◽  
Dae Hwan Kwon ◽  
Pyuck Pa Choi ◽  
Ji Soon Kim ◽  
...  

Nanosize nickel powders were successfully produced by electrical explosion of wire (EEW). In EEW, the nickel wire was discharged in a chamber filled with nitrogen or argon gas, and the produced powders were subsequently stabilized by air-passivation at room temperature for 2 h. X-ray diffraction only showed the nickel phase of FCC crystal structure, whereas TEM and XPS analyses showed the formation of a very thin oxide layer of NiO on the surface of particles. Particles were spherical in shape, and the mean particle size calculated by specific surface area was about 100 nm. The particle size decreased with increasing charging voltage and with increasing ambient gas pressure. Argon gas was more effective in producing finer particles than nitrogen gas.


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