scholarly journals Influence of Titania Synthesized by Pulsed Laser Ablation on the State of Platinum during Ammonia Oxidation

2020 ◽  
Vol 10 (14) ◽  
pp. 4699
Author(s):  
Andrey Stadnichenko ◽  
Dmitry Svintsitskiy ◽  
Lidiya Kibis ◽  
Elizaveta Fedorova ◽  
Olga Stonkus ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Ammonia Oxidation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Active Species ◽  
Laser Ablation In Liquid ◽  
X Ray ◽  
Catalytically Active ◽  
Physicochemical Methods

A set of physicochemical methods, including X-ray photoelectron spectroscopy (XPS), X-ray diraction, electron microscopy and X-ray absorption spectroscopy, was applied to study Pt/TiO2 catalysts prepared by impregnation using a commercial TiO2-P25 support and a support produced by pulsed laser ablation in liquid (PLA). The Pt/TiO2-PLA catalysts showed increased thermal stability due to the localization of the highly dispersed platinum species at the intercrystalline boundaries of the support particles. In contrast, the Pt/TiO2-P25 catalysts were characterized by uniform distributionof the Pt species over the support. Analysis of Pt4f XP spectra shows that oxidized Pt2+ and Pt4+ species are formed in the Pt/TiO2-P25 catalysts, while the platinum oxidation state in the Pt/TiO2-PLA catalysts is lower due to stronger interaction of the active component with the support due to stronginteraction via Pt-O-Ti bonds. The Pt4f XP spectra of the samples after reaction show Pt2+ and metallic platinum, which is the catalytically active species. The study of the catalytic properties in ammonia oxidation showed that, unlike the catalysts prepared with a commercial support, the Pt/TiO2-PLA samples show higher stability during catalysis and significantly higher selectivity to N2 in a wide temperature range of 200–400 C.

scholarly journals Synthesis and Properties of Platinum Nanoparticles by Pulsed Laser Ablation in Liquid

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Maria Isabel Mendivil Palma ◽  
Bindu Krishnan ◽  
Guadalupe Alan Castillo Rodriguez ◽  
Tushar Kanti Das Roy ◽  
David Avellaneda Avellaneda ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Pt Nanoparticles ◽  
Pulsed Laser Ablation ◽  
Laser Ablation In Liquid ◽  
Visible Absorption ◽  
Energy Fluence ◽  
Ablation Time

Platinum (Pt) nanoparticles were synthesized by pulsed laser ablation in liquid (PLAL) technique in different liquids (acetone, ethanol, and methanol). Ablation was performed using a Q-switched Nd:YAG laser with output energy of 230 mJ/pulse for 532 nm wavelength. Ablation time and laser energy fluence were varied for all the liquids. Effects of laser energy fluence, ablation time, and nature of the liquid were reported. The mean size, size distributions, shape, elemental composition, and optical properties of Pt nanoparticles synthesized by PLAL were examined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Visible absorption spectroscopy.

scholarly journals PL Tunable GaN Nanoparticles Synthesis through Femtosecond Pulsed Laser Ablation in Different Environments

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 439 ◽  
Author(s):  
Juan Hao ◽  
Sijia Xu ◽  
Bingrong Gao ◽  
Lingyun Pan
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Pulse Laser Ablation ◽  
Optoelectronic Devices ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Alternative Methods ◽  
X Ray ◽  
Pl Spectra ◽  
Bulk Gan

The tunable photoluminescence (PL) property is very important for gallium nitride (GaN) nanoparticles in the application of ultraviolet and blue optoelectronic devices, while conventional methods are not so satisfactory that alternative methods for preparing GaN nanoparticles should be studied. In this paper, ultra-small and well dispersed GaN nanoparticles are fabricated through femtosecond pulse laser ablation in air, water and ethanol. For the PL spectra of GaN nanoparticles, there are no shifts in air, red shifts in water and blue shifts in ethanol compared with the intrinsic PL spectra of bulk GaN. The X-ray photoelectron spectroscopy (XPS) results demonstrate that the various PL spectra can be due to the different components inside the GaN nanoparticles, which not only have effect on the PL emissions, but also greatly influence the intensity of PL. This study validates that the ablation environment has a great adjustable effect on the properties of GaN nanoparticles.

scholarly journals Deposit of AlN thin films by nitrogen reactive pulsed laser ablation using an Al target

2019 ◽  
Vol 65 (4 Jul-Aug) ◽  
pp. 345 ◽  
Author(s):  
F. Chale-Lara ◽  
M. Zapata-Torres ◽  
F. Caballero-Briones ◽  
W. De la Cruz ◽  
N. Cruz Gonzalez ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Hexagonal Phase ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Nitrogen Pressure ◽  
Binding Energies ◽  
Xps Spectra ◽  
X Ray

We report the synthesis of AlN hexagonal thin films by pulsed laser ablation, using Al target in nitrogen ambient over natively-oxidized Si (111) at 600°C. Composition and chemical state were determined by X-ray photoelectron spectroscopy (XPS); while structural properties were investigated using X-ray diffraction (XRD). High-resolution XPS spectra present a gradual shift to higher binding energies on the Al2ppeak when nitrogen pressure is incremented, indicating the formation of the AlN compound. At 30 mTorr nitrogen pressure, theAl2p peak corresponds to AlN, located at 73.1 eV, and the XRD pattern shows a hexagonal phase of AlN. The successful formation of the AlN compound is corroborated by UV-Vis reflectivity measurements.

scholarly journals Highly Defective Dark Nano Titanium Dioxide: Preparation via Pulsed Laser Ablation and Application

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2054 ◽  
Author(s):  
Elena D. Fakhrutdinova ◽  
Anastasiia V. Shabalina ◽  
Marina A. Gerasimova ◽  
Anna L. Nemoykina ◽  
Olga V. Vodyankina ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Visible Light ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Antibacterial Activities ◽  
Scanning Calorimetry ◽  
Laser Ablation In Liquid ◽  
X Ray ◽  
Nano Titanium Dioxide ◽  
Adsorption Desorption

The development of methods to synthesize and study the properties of dark titania is of the utmost interest due to prospects for its use, primarily in photocatalysis when excited by visible light. In this work, the dark titania powder was prepared by pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) in water and dried in air. To study the changes occurring in the material, the thermal treatment was applied. The structure, composition, and properties of the obtained powders were studied using transmission electron microscopy, low-temperature N2 adsorption/desorption, X-ray diffraction, thermogravimetry/differential scanning calorimetry, X-ray photoelectron, Raman and UV-vis spectroscopies, and photoluminescence methods. The processes occurring in the initial material upon heating were studied. The electronic structure of the semiconductor materials was investigated, and the nature of the defects providing the visible light absorption was revealed. The photocatalytic and antibacterial activities of the materials obtained were also studied. Dark titania obtained via laser ablation in liquid was found to exhibit catalytic activity in the phenol photodegradation process under visible light (>420 nm) and showed antibacterial activity against Staphylococcus aureus and bacteriostatic effect towards Escherichia coli.

Structural and optical properties of TiO2–Ge nanoparticles prepared through laser ablation in liquid medium

2017 ◽  
Vol 95 (7) ◽  
pp. 645-649 ◽  
Author(s):  
Shaista Shahzada ◽  
Anbarin Fatima ◽  
Asma Nazir ◽  
Arshad Mehmood ◽  
Mazhar Mehmood ◽  
...  
Keyword(s):  
Optical Properties ◽  
Laser Ablation ◽  
Average Particle Size ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Visible Range ◽  
Average Particle ◽  
Laser Ablation In Liquid ◽  
X Ray ◽  
Scanning Electron

Quantum dot (QD) composite nanoparticles of titania germanium (TiO2–Ge) were fabricated by pulsed laser ablation of composite targets of TiO2–Ge immersed in deionized water. The single phase crystallanity, lattice parameters, and the evaluation of crystallite size of nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the samples was analyzed through scanning electron microscopic studies. The average particle size calculated through XRD and measured through scanning electron microscope is in the range from 18 to 29 nm and are in agreement with each other. Compositional study was carried out through electron dispersive X-ray analysis showing that the ablation rate of Ge is smaller than TiO2. Optical properties were measured by UV–visible transmission spectra and Raman spectroscopy. The band gap of composite particles varies from the UV to the visible range by varying concentration of Ge QDs. This work shows that pulsed laser ablation in liquid media is an easy approach to synthesize ultrafine, contamination-free nanosized material, which is difficult to produce by other conventional methods.

scholarly journals Structural and Magnetic Properties of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4/ZnFe2O4 Spinel Ferrite Nanocomposites: Comparative Study between Sol-Gel and Pulsed Laser Ablation in Liquid Approaches

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2461
Author(s):  
Munirah A. Almessiere ◽  
Sadik Güner ◽  
Yassine Slimani ◽  
Mohammed Hassan ◽  
Abdulhadi Baykal ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Laser Ablation ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Magnetic Data ◽  
Laser Ablation In Liquid ◽  
X Ray ◽  
Magnetic Parameters

In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4)x/(ZnFe2O4)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (CNGaGdFO)x/(ZFO)y spinel ferrite nanocomposites (NC) have been synthesized by both sol-gel and Green pulsed laser ablation in liquid (PLAL) approaches. All products were characterized by X-ray powder diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), elemental mappings and energy dispersive X-ray spectroscopy (EDX). It was objected to tune the magnetic properties of a soft spinel ferrite material with a softer one by mixing them with different fractions. Some key findings are as follows. M-H investigations revealed the exhibition of ferrimagnetic phases for all synthesized samples (except ZnFe2O4) that were synthesized by sol-gel or PLAL methods at both 300 K and 10 K. ZnFe2O4 ferrite NPs exhibits almost paramagnetic feature at 300 K and glass-like phase at very low temperatures below 19.23 K. At RT analyses, maximum saturation magnetization (MS) of 66.53 emu/g belongs to nanocomposite samples that was synthesized by sol-gel method and x:y ratio of 1:3. At 10 K analyses, MS,max = 118.71 emu/g belongs to same nanocomposite samples with ratio of 1:3. Maximum coercivities are 625 Oe belonging to CNGaGdFO and 3564 Oe belonging to NC sample that was obtained by sol-gel route having the 3:1 ratio. Squareness ratio (SQRs = Mr/MS) of NC sample (sol-gel, 4:1 ratio) is 0.371 as maximum and other samples have much lower values until a minimum of 0.121 (laser, 3:1) assign the multi-domain wall structure for all samples at 300 K. At 10 K data, just CNGaGdFO has 0.495 SQR value assigning single domain nature. The maximum values of effective crystal anisotropy constant (Keff) are 5.92 × 104 Erg/g and 2.4 × 105 Erg/g belonging to CNGaGdFO at 300 K and 10 K, respectively. Further, this sample has an internal anisotropy field Ha of 1953 Oe as largest at 300 K. At 10 K another sample (sol-gel, 3:1 ratio) has Ha,max of 11138 Oe which can also be classified as a soft magnetic material similar to other samples. Briefly, most magnetic parameters of NCs that were synthesized by sol-gel route are stronger than magnetic parameters of the NCs that were synthesized by PLAL at both temperatures. Some NC samples were observed to have stronger magnetic data as compared to magnetic parameters of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 NPs at 10 K.

scholarly journals Synthesis of gold nanoparticles by laser ablation on porous silicon for sensing CO2 gas

2018 ◽  
Vol 16 (36) ◽  
pp. 1-10
Author(s):  
Uday Muhsin Nayef
Keyword(s):  
Laser Ablation ◽  
Porous Silicon ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
X Ray Diffraction ◽  
Laser Ablation In Liquid ◽  
Co2 Gas ◽  
X Ray ◽  
P Type ◽  
Si Wafer

In this research, porous silicon (PS) prepared by anodization etching on surface of single crystalline p-type Si wafer, then Gold nanoparticle (AuNPs) prepared by pulsed laser ablation in liquid. NPs deposited on PS layer by drop casting. The morphology of PS, AuNPs and AuNPs/PS samples were examined by AFM. The crystallization of this sample was characterized by X-ray diffraction (XRD). The electrical properties and sensitivity to CO2 gas were investigated to Al/AuNPs/PS/c-Si/Al, we found that AuNPs plays crucial role to enhance this properties.

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