scholarly journals Structural Characterizations of Palladium Clusters Prepared by Polyol Reduction of [PdCl4]2−Ions

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Loredana Schiavo ◽  
Lucrezia Aversa ◽  
Roberta Tatti ◽  
Roberto Verucchi ◽  
Gianfranco Carotenuto
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Nucleating Agent ◽  
X Ray Diffraction ◽  
Palladium Clusters ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrogen Technology ◽  
Physical And Chemical

Palladium nanoparticles are of great interest in many industrial fields, ranging from catalysis and hydrogen technology to microelectronics, thanks to their unique physical and chemical properties. In this work, palladium clusters have been prepared by reduction of [PdCl4]2−ions with ethylene glycol, in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) as stabilizer. The stabilizer performs the important role of nucleating agent for the Pd atoms with a fast phase separation, since palladium atoms coordinated to the polymer side-groups are forced at short distances during nucleation. Quasispherical palladium clusters with a diameter of ca. 2.6 nm were obtained by reaction in air at 90°C for 2 hours. An extensive materials characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other characterizations (TGA, SEM, EDS-SEM, and UV-Vis) has been performed in order to evaluate the structure and oxidation state of nanopalladium.

Core–shell structures with metallic silver as nucleation agent of low expansion phases in BaO/SrO/ZnO/SiO2 glasses

CrystEngComm ◽  
2019 ◽  
Vol 21 (29) ◽  
pp. 4373-4386 ◽  
Author(s):  
Christian Thieme ◽  
Michael Kracker ◽  
Katrin Thieme ◽  
Christian Patzig ◽  
Thomas Höche ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Nucleating Agent ◽  
Shell Structures ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The role of silver as a nucleating agent in BaO/SrO/ZnO/SiO2 glasses is studied with a range of microstructure-characterization techniques, such as scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray diffraction.

scholarly journals Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 195
Author(s):  
Snežana S. S. Nenadović ◽  
Ljiljana M. Kljajević ◽  
Marija M. Ivanović ◽  
Miljana M. Mirković ◽  
Nadežda Radmilović ◽  
...  
Keyword(s):  
Rare Earth ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Alkali Activation ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Na Ions

The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides.

Preparation of Pd/γ-Al2O3 Nanocatalyst and Characterization by X-Ray Diffraction and Transmission Electron Microscope

2013 ◽  
Vol 685 ◽  
pp. 312-315
Author(s):  
Karim. H. Hassan
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Selective Hydrogenation ◽  
Chemical Properties ◽  
Impregnation Method ◽  
Activated Alumina ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Physical And Chemical

In petrochemical industry, and mainly in ethylene production plants, acetylene presents in trace amount in ethylene gas and causes a serous problems owing to it is higher activity and being explosive at certain concentration limits with air, so it has to be converted to ethylene in selective hydrogenation. Three selective hydrogenation nanocatalysts Pd/γ-Al2O3 that contain 0.03 %, 0.05% and 0.07 wt % of palladium loaded on activated alumina were prepared by impregnation method. They were characterized for physical and chemical properties and structurally by X-ray diffraction, metal dispersion, and transmission electron microscope.

Characterization of Y/TiO2 Nanoparticles and their Reactivity for CO2 Photoreduction

2011 ◽  
Vol 55-57 ◽  
pp. 1506-1510 ◽  
Author(s):  
Jing Wei ◽  
Xin Tan ◽  
Tao Yu ◽  
Lin Zhao
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Illumination ◽  
Transmission Electron ◽  
And Chemical Properties

A series of Y/TiO2nanoparticles (NPs) were synthesized via sol-gel method. The crystal structures, morphologies and chemical properties were characterized using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). We investigated the effects of different doping amounts of Y on the reaction of CO2photoreduction. The results shown that 0.1 wt.%Y/TiO2(0.1YT) performed the highest photocatalytic activity, which yielded 384.62 µmol/g∙cat. formaldehyde after 6 h of UV illumination.

scholarly journals CVD-Grown 2D Nonlayered NiSe as a Broadband Photodetector

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1066
Author(s):  
Fang Liang ◽  
Liangliang Zhan ◽  
Tianyu Guo ◽  
Xing Wu ◽  
Junhao Chu
Keyword(s):  
Crystal Structure ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Microscopy Study ◽  
Chemical Vapor Deposition Method ◽  
Layered Crystal ◽  
X Ray ◽  
Transmission Electron ◽  
Physical And Chemical

Two-dimensional (2D) materials have expansive application prospects in electronics and optoelectronics devices due to their unique physical and chemical properties. 2D layered materials are easy to prepare due to the layered crystal structure and the interlayer van der Waals combination. However, the 2D nonlayered materials are difficult to prepare due to the nonlayered crystal structure and the combination of interlayer isotropic chemical bonds, resulting in limited research on 2D nonlayered materials with broad characteristics. Here, a 2D nonlayered NiSe material has been synthesized by a chemical vapor deposition method. The atomic force microscopy study shows that the grown NiSe with a thin thickness. Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy results demonstrate the uniformity and high quality of NiSe flakes. The NiSe based photodetector realizes the laser response to 830 nm and 10.6 μm and the maximum responsivity is ~6.96 A/W at room temperature. This work lays the foundation for the preparation of 2D nonlayered materials and expands the application of 2D nonlayered materials in optoelectronics fields.

MORPHOLOGICAL AND COMPOSITIONAL STUDY AT THE Si/Fe INTERFACE OF (Fe/Si) MULTILAYER

SPIN ◽  
2014 ◽  
Vol 04 (01) ◽  
pp. 1440002 ◽  
Author(s):  
L. BADÍA-ROMANO ◽  
J. RUBÍN ◽  
F. BARTOLOMÉ ◽  
J. BARTOLOMÉ ◽  
S. OVCHINNIKOV ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Large Fraction ◽  
Chemical Properties ◽  
Morphological Characterization ◽  
Silicide Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Nanostructured Systems ◽  
Scanning Transmission ◽  
Physical And Chemical

Diffusion and reaction of elements at the interfaces of nanostructured systems play an important role in controlling their physical and chemical properties for subsequent applications. ( Fe / Si ) nanolayers were prepared by thermal evaporation under ultrahigh vacuum onto a Si (100) substrate. A morphological characterization of these films was performed by combination of scanning transmission electron microscopy (STEM) and X-ray reflectivity (XRR). The compositional depth profile of the ( Fe / Si ) structures was obtained by angle resolved X-ray photoelectron spectroscopy (ARXPS) and hard X-ray photoelectron spectroscopy (HAXPES). Moreover, determination of the stable phases formed at the Si on Fe interfaces was performed using conversion electron Mössbauer spectroscopy. The Si / Fe interface thickness and roughness were determined to be 1.4 nm and 0.6 nm, respectively. A large fraction of the interface is composed of c- Fe 1-x Si paramagnetic phase, though a minoritary ferromagnetic Fe rich silicide phase is also present.

scholarly journals Surface Properties and Denitrification Performance of Impurity-Removed Rare Earth Concentrate

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 580
Author(s):  
Kai Zhang ◽  
Yuze Bai ◽  
Zhijun Gong ◽  
Zengwu Zhao ◽  
Baowei Li ◽  
...  
Keyword(s):  
Rare Earth ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Chemical Properties ◽  
Acid Leaching ◽  
X Ray Diffraction ◽  
Acid Base ◽  
X Ray ◽  
Temperature Programmed ◽  
Physical And Chemical

Acid leaching and alkali roasting were used to remove impurities such as Ca and Si in Baiyun Obo rare earth concentrate. The effects of acid–base treatment on the physical and chemical properties of the samples were analyzed by scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller characterization, X-ray photoelectron spectroscopy, H2-temperature-programmed reduction, NH3-temperature-programmed desorption (TPD), and NO-TPD. Results showed that the content of Ce7O12 in the rare earth concentrates increased and the dispersion was uniform. The grains became smaller, the specific surface area of rare earth concentrates increased, and the active sites were more exposed. Ce coexisted in the form of Ce3+ and Ce4+, whereas Fe coexisted in the form of Fe3+ and Fe2+. The content of Fe3+ was increased. The acid–base-treated rare earth concentrates had a denitration efficiency of 87.4% at a reaction temperature of 400 °C.

Influence of tungsten sources on the synthesis and properties of ammonium dioxothiotungstate

2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Yunfei Bi ◽  
Shuangqin Zeng ◽  
Dadong Li ◽  
Hong Nie
Keyword(s):  
Tungsten Oxide ◽  
Chemical Properties ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Detailed Characteristic ◽  
Temperature Programmed ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractAmmonium dioxothiotungstate was synthesized using different tungsten sources and characterized in detail by powder X-ray diffraction, energy dispersive X-ray spectrometry, transmission electron microscopy, nitrogen adsorption, and temperature-programmed sulfidation. It was found that tungsten oxide nanobelts are superior to ammonium metatungstate as tungsten source for the synthesis of ammonium dioxothiotungstate due to a time-consuming aging step being excluded from the synthesis route. Moreover, detailed characteristic data reveal that, when tungsten oxide nanobelts are used, the physical and chemical properties of the resulting ammonium dioxothiotungstate including particles size, specific surface area, and sulfidation pattern were improved. Also, the hydrodesulfurization measurements showed higher catalytic activity and balanced selectivity of the resulting ammonium dioxothiotungstate.

AN OVERVIEW OF SILVER NANOPARTICLES

2021 ◽  
Vol 12 (4) ◽  
pp. 170-175
Author(s):  
M Mohan Varma ◽  
Indukuri Kinnera
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Localized Surface Plasmon ◽  
Nano Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Biological Technique ◽  
Physical And Chemical

During the past few years, silver nanoparticles became one amongst the foremost investigated and explored technology derived nanostructures, given the fact that nano silver primarily based materials established to possess attention-grabbing, challenging, and inspiring characteristics appropriate for numerous applications. Generation after generation, the postulates come back forth regarding properties of silver for the traditional Greeks cook from silver pots and the recent saying “born with silver spoon in his mouth” so show that ingestion with a silver spoon was renowned as uncontaminated. Silver has an excessive amount of contemporary industrial uses and is considered as a store of wealth. Silver nanoparticles are unit one amongst the foremost very important and interesting nano materials among many metals like nanoparticles. they need been urban as a complicated unit within the field of nanotechnology. This review predominately focused on advantages and synthesis of silver nanoparticles using physical, chemical, and biological ways. However, physical, and chemical methods are harmful and expensive however the biological technique is easy, rapid, non- noxious and ecofriendly. It additionally explains regarding mechanism of action, numerous characterization techniques as well as UV- Visible Spectroscopy, Localized Surface Plasmon Resonance (LSPR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy, X- ray Photoelectron Spectroscopy (XPS), Dynamic Light Scattering (DLS), Zeta Potential and finally concluded with numerous applications.

Improvement of physico-chemical properties by addition of H2O2: An extensive case study on the RE-doped ceria system (RE = Gd, Sm)

2009 ◽  
Vol 24 (9) ◽  
pp. 2845-2854 ◽  
Author(s):  
Balaji P. Mandal ◽  
Vinita Grover ◽  
Mrinal R. Pai ◽  
Avesh K. Tyagi
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Powder Properties ◽  
Temperature Programmed

Effect of H2O2 on synthesis and powder properties such as surface area and agglomerate size of nanocrystalline Ce0.8M0.2O1.90 (M: Sm, Gd) was explored by treating cerium nitrate and rare-earth nitrate with NaOH in the presence/absence of H2O2. The resultant products were characterized by x-ray diffraction, Raman spectroscopy, thermo-gravimetry–differential thermal analysis, dynamic light scattering, surface area analysis, high-resolution transmission electron microscopy, and x-ray photoelectron spectroscopy. The presence of H2O2 was found to have a profound effect on powder properties such as surface area and particle size of these doped ceria samples and results in smaller crystallite size, softer agglomerates, and larger surface area. A mechanism is proposed to explain the observed better powder properties of the samples. It was also shown that the samples prepared in the presence of H2O2 can lower the conversion temperature of CO to CO2, proving these to be better catalysts. Interestingly, temperature-programmed reduction studies on Sm3+-doped samples showed that the doping in conjunction with the use of H2O2 leads to enhanced reduction properties of the samples over multiple cycles.

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