scholarly journals Instrumental Techniques for Characterization of Molybdenum Disulphide Nanostructures

2020 ◽  
Vol 2020 ◽  
pp. 1-29
Author(s):  
Kabelo E. Ramohlola ◽  
Emmanuel I. Iwuoha ◽  
Mpitloane J. Hato ◽  
Kwena D. Modibane
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Analytical Techniques ◽  
Great Accuracy ◽  
Molybdenum Disulphide ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Electron Microscopies ◽  
Energy Applications ◽  
Transmission Electron

The excellent chemical and physical properties of materials (nanomaterials) with dimensions of less than 100 nm (nanometers) resulted in researchers and industrialists to have great interest in their discovery and applications in various systems/applications. As their sizes are reduced to nanoscale, these nanomaterials tend to possess exceptional properties differing from those of their bulk counterparts; hence, they have found applications in electronics and medicines. In order to apply them in those applications, there is a need to synthesise these nanomaterials and study their structural, optical, and electrochemical properties. Among several nanomaterials, molybdenum disulphide (MoS2) has received a great interest in energy applications due to its exceptional properties such as stability, conductivity, and catalytic activities. Hence, the great challenge lies in finding the state-of-the-art characterization techniques to reveal the different properties of MoS2 nanostructures with great accuracy. In this regard, there is a need to study and employ several techniques to accurately study the surface chemistry and physics of the MoS2 nanostructures. Hence, this review will comprehensively discuss a detailed literature survey on analytical techniques that can be used to study the chemical, physical, and surface properties of MoS2 nanostructures, namely, ultraviolet-visible spectroscopy (UV-vis), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, time-of-flight secondary ion mass spectroscopy (TOF-SIMS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopies (SEM and TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS/X), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and electroanalytical methods which include linear sweep (LSV) and cyclic (CV) voltammetry and electrochemical impedance spectroscopy (EIS).

scholarly journals Amorphous Ni x Co y P-supported TiO2 nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

2019 ◽  
Vol 10 ◽  
pp. 62-70 ◽  
Author(s):  
Yong Li ◽  
Peng Yang ◽  
Bin Wang ◽  
Zhongqing Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nanotube Arrays ◽  
Active Surface Area ◽  
X Ray ◽  
Transmission Electron

Bimetallic phosphides have been attracting increasing attention due to their synergistic effect for improving the hydrogen evolution reaction as compared to monometallic phosphides. In this work, NiCoP modified hybrid electrodes were fabricated by a one-step electrodeposition process with TiO2 nanotube arrays (TNAs) as a carrier. X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties of the samples. The electrochemical performance was investigated by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. We show that after incorporating Co into Ni–P, the resulting Ni x Co y P/TNAs present enhanced electrocatalytic activity due to the improved electron transfer and increased electrochemically active surface area (ECSA). In 0.5 mol L−1 H2SO4 electrolyte, the Ni x Co y P/TNAs (x = 3.84, y = 0.78) demonstrated an ECSA value of 52.1 mF cm−2, which is 3.8 times that of Ni–P/TNAs (13.7 mF cm−2). In a two-electrode system with a Pt sheet as the anode, the Ni x Co y P/TNAs presented a bath voltage of 1.92 V at 100 mA cm−2, which is an improvment of 79% over that of 1.07 V at 10 mA cm−2.

Magnetic Nanoparticle Supported Ionic Liquid Phase Catalyst for Oxidation of Alcohols

2020 ◽  
Vol 73 (11) ◽  
pp. 1088
Author(s):  
Altafhusen Naikwade ◽  
Megha Jagadale ◽  
Dolly Kale ◽  
Gajanan Rashinkar
Keyword(s):  
Ionic Liquid ◽  
Liquid Phase ◽  
Photoelectron Spectroscopy ◽  
Magnetic Nanoparticle ◽  
Analytical Techniques ◽  
X Ray ◽  
Supported Ionic Liquid ◽  
Transmission Electron ◽  
Oxidation Of Alcohols ◽  
Ft Ir

A new magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetric analysis, energy dispersive X-ray analysis, and vibrating sample magnetometer analysis ascertained the successful formation of catalyst. The performance of a magnetically retrievable SILP catalyst was evaluated in the selective oxidation of alcohols. The split test and leaching studies of the SILP catalyst confirmed its heterogeneous nature. In addition, the reusability potential of SILP catalyst was also investigated which revealed its robust activity up to six consecutive cycles.

One-Pot Hydrothermal Synthesis of Sulfur-Doped SnO2 Nanoparticles and their Enhanced Photocatalytic Properties

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650035 ◽  
Author(s):  
Lin Ma ◽  
Limei Xu ◽  
Xuyao Xu ◽  
Xiaoping Zhou ◽  
Lingling Zhang
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Sno2 Nanoparticles ◽  
Light Response ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Light Region ◽  
Vis Spectroscopy

Sulfur-doped SnO2 nanoparticles with ultrafine sizes have been successfully prepared by a one-pot hydrothermal method. The obtained samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), thermogravimetric (TG), analyzer UV-Vis spectroscopy, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the doping level of sulfur element as well as the bandgaps of SnO2 can be controlled to a certain extent by varying the amount of L-cysteine (L-cys). When evaluated as photocatalysts in the degradation of rhodamine B (RhB) and reduction of Cr(VI) under visible light region, the resultant sulfur-doped SnO2 nanoparticles demonstrate obviously enhanced photocatalytic activities due to the markedly improved visible light response and effective separation of the photo-generated electron–hole pairs.

scholarly journals Synthesis and Characterization of PdAgNi/C Trimetallic Nanoparticles for Ethanol Electrooxidation

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2244
Author(s):  
Ahmed Elsheikh ◽  
James McGregor
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Active Surface ◽  
Active Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Steady State Current ◽  
Xrd Patterns ◽  
Co Reduction

The direct use of ethanol in fuel cells presents unprecedented economic, technical, and environmental opportunities in energy conversion. However, complex challenges need to be resolved. For instance, ethanol oxidation reaction (EOR) requires breaking the rigid C–C bond and results in the generation of poisoning carbonaceous species. Therefore, new designs of the catalyst electrode are necessary. In this work, two trimetallic PdxAgyNiz/C samples are prepared using a facile borohydride reduction route. The catalysts are characterized by X-ray diffraction (XRD), Energy-Dispersive X-ray spectroscopy (EDX), X-ray photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM) and evaluated for EOR through cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The XRD patterns have shown a weak alloying potential between Pd, and Ag prepared through co-reduction technique. The catalysts prepared have generally shown enhanced performance compared to previously reported ones, suggesting that the applied synthesis may be suitable for catalyst mass production. Moreover, the addition of Ag and Ni has improved the Pd physiochemical properties and electrocatalytic performance towards EOR in addition to reducing cell fabrication costs. In addition to containing less Pd, The PdAgNi/C is the higher performing of the two trimetallic samples presenting a 2.7 A/mgPd oxidation current peak. The Pd4Ag2Ni1/C is higher performing in terms of its steady-state current density and electrochemical active surface area.

Nanostructured manganese oxides and their composites with carbon nanotubes as electrode materials for energy storage devices

2008 ◽  
Vol 80 (11) ◽  
pp. 2327-2343 ◽  
Author(s):  
V. Subramanian ◽  
Hongwei Zhu ◽  
Bingqing Wei
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Manganese Oxides ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Analytical Techniques ◽  
Energy Storage Devices ◽  
X Ray ◽  
Storage Devices

Manganese oxides have been synthesized by a variety of techniques in different nanostructures and studied for their properties as electrode materials in two different storage applications, supercapacitors (SCs) and Li-ion batteries. The composites involving carbon nanotubes (CNTs) and manganese oxides were also prepared by a simple room-temperature method and evaluated as electrode materials in the above applications. The synthesis of nanostructured manganese oxides was carried out by simple soft chemical methods without any structure directing agents or surfactants. The prepared materials were well characterized using different analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), surface area studies, etc. The electrochemical properties of the nanostructured manganese oxides and their composites were studied using cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopic (EIS) studies. The influence of structural/surface properties on the electrochemical performance of the synthesized manganese oxides is reviewed.

scholarly journals Au/TiO2Reusable Photocatalysts for Dye Degradation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Silija Padikkaparambil ◽  
Binitha Narayanan ◽  
Zahira Yaakob ◽  
Suraja Viswanathan ◽  
Siti Masrinda Tasirin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron ◽  
Uv Visible

Nanogold doped TiO2catalysts are synthesized, and their application in the photodegradation of dye pollutants is studied. The materials are characterized using different analytical techniques such as X-ray diffraction, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The results revealed the strong interaction between the metallic gold nanoparticles and the anatase TiO2support. Au doped systems showed very good photoactivity in the degradation of dye pollutants under UV irradiation as well as in sunlight. A simple mechanism is proposed for explaining the excellent photoactivity of the systems. The reusability studies of the photocatalysts exhibited more than 98% degradation of the dye even after 10 repeated cycles.

scholarly journals Pentavalent Vanadium Species as Potential Corrosion Inhibitors of Al2Cu Intermetallic Phase in the Sulfuric(VI) Acid Solutions

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1946 ◽  
Author(s):  
Przemysław Kwolek ◽  
Barbara Kościelniak ◽  
Magdalena Wytrwal-Sarna
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Intermetallic Phase ◽  
Open Circuit ◽  
Acid Solutions ◽  
Scanning Calorimetry ◽  
Electrochemical Impedance Spectra ◽  
X Ray

The objective of this work was to test vanadium isopolyoxoanions as potential corrosion inhibitors of the intermetallic phase Al2Cu in sulfuric acid solutions at pH = 1.3 and 2.5. The intermetallic was melted in an electric arc furnace. Its phase composition was confirmed using X-ray diffraction, light microscopy, and differential scanning calorimetry. Then Al2Cu corrosion kinetics was studied. Chemical composition of the solution after corrosion was determined using inductively coupled plasma-optical emission spectroscopy. The surface of corroded specimens was analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. Subsequent electrochemical studies involved determination of open-circuit potential, electrochemical impedance spectra, and polarization curves. It was found that the Al2Cu phase corrodes selectively and vanadium isopolyoxoanions increase this process both at pH = 1.3 and 2.5 with two exceptions. Corrosion inhibition was observed for 100 and 200 mM of Na3VO4 at pH 1.3, with inhibition efficiency 78% and 62% respectively, due to precipitation of V2O5.

Structure and Phase Transformations in Thermoelastic Ni(1−x)TiCux) Thin Films Prepared by D.C. Magnetron Sputtering.

1990 ◽  
Vol 187 ◽  
Author(s):  
L. Chang ◽  
C. Hu-Simpsono ◽  
D. S. Grummon ◽  
W. Pratt ◽  
R. loloee
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Phase Transformations ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sputtered Films ◽  
Transmission Electron ◽  
Shape Memory Effects

AbstractThe intermetallic compound NiTi and its copper containing variants, Ni(1−x)TiCu(x), are capableof stress induced displacive tansformations which give rise to superelasticity and shape-memory effects. Thin films of these alloys, which may find use as sensors, microactuators, or as protective surface microalloys, are of increasing interest. In this study, thin films in the Ni(1−x)TiCUx) system, ranging in thickness from 250 nm to 5 μm, were prepared with a triode-type D.C. magnetron sputtering apparatus using a ternary alloy target. Both homogeneous films and periodic multilayer structures (with interspersed Ti-rich layers) were fabricated. of particular interest were shifts in composition with respect to the target, and the structural and phase transformation characteristics of the sputtered films. These phenomena were examined using transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray microanalysis. Transformation temperatures and enthalpies were determined by differential scanning calorimetry and confirmed by 4-point D.C. resistivity measurements. The as-sputtered films were amorphousbut crystallized during annealing at 923K. Electron diffraction and XPS data suggested the presence of oxygen. Single layer film compositions were shifted to slightly lower Ti fractions which depressed the onset of the transformation sequence by ˜35K and degraded phase stability during annealing. It was possible, however, to produce periodic multilayer films which showed evidence of thermoelastic phase transformations during DSC, resistivity, and in-situ TEM experiments. These films were stable with respect to vacuum annealing at 923 K for 6 h.

Layered in situ copper/polyimide composite films

1988 ◽  
Vol 3 (2) ◽  
pp. 211-214 ◽  
Author(s):  
G. M. Porta ◽  
L. T. Taylor
Keyword(s):  
Relative Humidity ◽  
Photoelectron Spectroscopy ◽  
Chemical Nature ◽  
Composite Films ◽  
Analytical Techniques ◽  
Copper Layer ◽  
X Ray ◽  
Transmission Electron ◽  
Physical And Chemical

Incorporation of bis (trifluoroacetylacetonato) copper (II), Cu (TFA)2 into poly (amide acid) prior to imidization produces bi-and trilayered composite films upon curing. Choice of curing atmosphere and concentration of dopant control the formation of a particular layered structure. Dry air and 100% relative humidity are the curing atmospheres used. The trilayered films are typified by a zero-valent copper layer sandwiched between a thin polyimide overlayer and the bulk polyimide. Curing in 100% relative humidity produces the thinnest overlayer. By doubling the dopant concentration used to prepare the trilayered films, bilayered films will result upon curing. In this instance the lack of a polyimide overlayer affords the oxidation of copper at the surface to copper (II) oxide. In each case the formation of the copper layer results from the migration of all Cu (TFA)2 from a depth of approximately 2000 Å to the surface where subsequent reactions take place. Several [Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM)] analytical techniques are used to characterize the physical and chemical nature of the films.

scholarly journals Effect of High Temperature Sodium Hydroxide Immersion on Fusion Bond Epoxy Coating

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Amal Al-Borno ◽  
Xianyi Chen ◽  
Shailesh Kewaldas Dhoke
Keyword(s):  
Sodium Hydroxide ◽  
Electrochemical Impedance ◽  
Analytical Techniques ◽  
Attenuated Total Reflection ◽  
Low Molecular Weight ◽  
Scanning Calorimetry ◽  
Premature Failure ◽  
X Ray ◽  
Deposit Layer

Fusion Bond Epoxy (FBE) coating system was exposed to 5% sodium hydroxide at elevated temperature for 30 days. The result of exposure showed formation of adhere deposit layer, a discolored zone underneath and remaining un-affected bulk of the coating. The deterioration of the coating was characterized using analytical techniques like scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), pull-off adhesion, and electrochemical impedance spectroscopy (EIS). Results obtained indicated chemical deterioration of the coating in the discolored zone and leaching of low molecular weight coating component forming deposit layer. Although the adhesion strength and barrier property were not affected, the polymer matrix in the affected zone undergoes severe changes in its surface microstructure, primary chemical structure, and glass transition temperature. This may inflict serious impairment of the coating functional properties and premature failure of the coating in long term exposure.

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