scholarly journals Investigating the existence of oxygen interstitial in CuCr1􀀀xMgxO2 [0.00 X 0.30] thermoelectric materials by X-Ray photoelectron spectroscopy [XPS]

2021 ◽  
Vol 5 (2) ◽  
pp. first
Author(s):  
Dũng Hoàng Văn ◽  
Anh Tuấn Thanh Phạm ◽  
Thư Nguyễn Bảo Lê ◽  
Trương Hữu Nguyễn ◽  
Thắng Bách Phan ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Photoelectron Spectroscopy ◽  
Fossil Fuel ◽  
Research Trend ◽  
X Ray ◽  
Oxygen Interstitial ◽  
Small Ratio ◽  
Properties Of Materials ◽  
Doping Ratio ◽  
Significant Attention

Climate change is promoting researches on materials which is capable of converting environmentally friendly energy, in which materials that convert heat into electricity are receiving significant attention, because their ability of converting heat to electricity not only generates the electricity but also contributes to slow down the consumption of fossil fuel. The existence of point defects in the semiconductors greatly effected properties of materials, especially thermoelectric properties. Therefore, the study of defects in materials is a popular research trend today. In this study, we focus on evaluating the existence of oxygen interstitial in CuCr1􀀀xMgxO2 [0.00 x 0.30] compounds, because oxygen interstitial greatly affected the thermoelectric properties of this material. Based on X-ray photoelectron spectroscopy (XPS) analysis, at the large ratio of Mg impurity x = 0.15, the compound had the highest percentage of oxygen interstitial and was also a good thermoelectric material. In addition, it could be also seen that CuCrO2 material being doped a large Mg doping ratio (x = 0.15) was suitable for thermal-to-electrical applications rather than the ones with a small ratio (x 0.05).

Electronic Structure and Thermoelectric Properties of Ytterbium-Filled Skutterudites

2001 ◽  
Vol 691 ◽  
Author(s):  
Hiroaki Anno ◽  
Kazuhiro Ashida ◽  
Kakuei Matsubara ◽  
George S. Nolas ◽  
Koji Akai ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Properties ◽  
Photoelectron Spectroscopy ◽  
Figure Of Merit ◽  
High Electron ◽  
Thermoelectric Figure ◽  
Electron Model ◽  
X Ray ◽  
Strong Hybridization ◽  
Filled Skutterudites

ABSTRACTThe electronic structure and thermoelectric properties of Yb partially filled CoSb3 skutterudite compounds have been investigated by x-ray photoelectron spectroscopy and band calculation in terms of an itinerant f electron model. In these materials, the significant effect of Yb filling is the large reduction of lattice thermal conductivity, remaining relatively high electron mobility and Seebeck coefficient, resulting in high thermoelectric figure of merit. We discuss the effects of the valence fluctuation between Yb2+ and Yb3+ and the strong hybridization of Yb 4f states with the valence band states on the electronic properties and their relation to thermoelectric properties for Yb partially filled CoSb3 compounds.

scholarly journals Synthesis, Characterization and Catalytic Activity of UiO-66-NH2 in the Esterification of Levulinic Acid

Applied Nano ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 344-358
Author(s):  
Daiana A. Bravo Fuchineco ◽  
Angélica C. Heredia ◽  
Sandra M. Mendoza ◽  
Enrique Rodríguez-Castellón ◽  
Mónica E. Crivello
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Microwave Plasma ◽  
Raw Materials ◽  
Metal Organic Framework ◽  
Research Trend ◽  
Infrared Spectrometry ◽  
X Ray ◽  
Ethyl Levulinate

The massive use of petroleum and its possible exhaustion are driving the current research trend to study alternative raw materials from biomass for organic reactions. In this context, the present article presents a study of the catalytic esterification of levulinic acid, a platform molecule, with ethanol. Metal-organic framework (MOF) type compounds UiO-66-NH2 have been synthesized. Zirconium was incorporated, using zirconium chloride as a metal precursor, together with 2-aminoterephthalic acid as an organic binding agent. An alternative route of synthesis was proposed using more favorable conditions from an economic and environmental point of view, replacing dimethylformamide by 50 and 75% acetone as substitute solvent. The physicochemical properties of the materials were evaluated by X-ray diffraction (XRD), Infrared Spectrometry with Fourier Transform (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), microwave plasma atomic emission spectroscopy (MP-AES) and N2 adsorption to understand their morphology, crystalline, chemical and pore structure. The progress of the reaction was followed by gas chromatography and mass spectroscopy. The catalytic activity result of MOF25% in autoclave reactor, showed 100% of selectivity to ethyl levulinate and a turnover number (TON) of 66.18 moles of product/moles of Zr. This good catalytic performance obtained by partial solvent replacement in the synthetic material provides a more economical and eco-friendly process for ethyl levulinate generation.

scholarly journals The chemistry of Cr(VI) adsorption on to poly(p-phenylenediamine) adsorbent

2018 ◽  
Vol 78 (12) ◽  
pp. 2481-2488
Author(s):  
Lindani Mdlalose ◽  
Mohammed Balogun ◽  
Maris Klavins ◽  
Christopher Deeks ◽  
Jon Treacy ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorptive Capacity ◽  
Redox Potentials ◽  
Amino Groups ◽  
X Ray ◽  
Adsorbent Surface ◽  
Alkaline Conditions ◽  
Ft Ir ◽  
Significant Attention ◽  
Ft Ir Spectroscopy

Abstract Water pollution due to industrial processes has necessitated and spurred robust research into the development of adsorbent materials for remediation. Polyphenylenediamines (PPD) have attracted significant attention because of their dual cationic and redox properties. They are able to reduce Cr(VI) to Cr(III) in solution. Interrogation of the chemical processes involved in the Cr(VI) adsorption on para-PPD was primarily by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. It was confirmed that the underlying oxidation of the amino groups to imines during the reduction of Cr(VI) to Cr(III) was irreversible. This process occurred at both acidic and alkaline conditions. Reduction was accompanied by Cr(III) chelation on the adsorbent surface. Further, regeneration with dilute aqueous NaOH and HCl extended the polymer's adsorptive capacity beyond exhaustion of its redox potentials.

scholarly journals Fabrication of PEDOT: PSS-PVP Nanofiber-Embedded Sb2Te3 Thermoelectric Films by Multi-Step Coating and Their Improved Thermoelectric Properties

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2835
Author(s):  
Sang-il Kim ◽  
Kang Yeol Lee ◽  
Jae-Hong Lim
Keyword(s):  
Thermoelectric Properties ◽  
Power Factor ◽  
Photoelectron Spectroscopy ◽  
Hybrid Composites ◽  
Composite Films ◽  
X Ray Diffraction ◽  
Thermoelectric Efficiency ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Electrical Conductivities

Antimony telluride thin films display intrinsic thermoelectric properties at room temperature, although their Seebeck coefficients and electrical conductivities may be unsatisfactory. To address these issues, we designed composite films containing upper and lower Sb2Te3 layers encasing conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)- polyvinylpyrrolidone(PVP) nanowires. Thermoelectric Sb2Te3/PEDOT:PSS-PVP/Sb2Te3(ED) (STPPST) hybrid composite films were prepared by a multi-step coating process involving sputtering, electrospinning, and electrodeposition stages. The STPPST hybrid composites were characterized by field-emission scanning electron microscopy, X-ray diffraction, ultraviolet photoelectron spectroscopy, and infrared spectroscopy. The thermoelectric performance of the prepared STPPST hybrid composites, evaluated in terms of the power factor, electrical conductivity and Seebeck coefficient, demonstrated enhanced thermoelectric efficiency over a reference Sb2Te3 film. The performance of the composite Sb2Te3/PEDOT:PSS-PVP/Sb2Te3 film was greatly enhanced, with σ = 365 S/cm, S = 124 μV/K, and a power factor 563 μW/mK.

Influence of Heat Treatment in Air on Thermoelectric Silicon Clathrate

2014 ◽  
Vol 617 ◽  
pp. 243-246 ◽  
Author(s):  
Hiroaki Anno ◽  
Ritsuko Shirataki
Keyword(s):  
Heat Treatment ◽  
Thermoelectric Properties ◽  
Photoelectron Spectroscopy ◽  
Surface Oxidation ◽  
Oxide Phase ◽  
Heat Treatments ◽  
Nominal Composition ◽  
X Ray ◽  
Silicon Clathrate ◽  
Before And After

The influence of heat treatments in air on the surface and thermoelectric properties of polycrystalline silicon clathrate of nominal composition Ba8Al15Si31was investigated. The samples were prepared by combining arc melting and spark plasma sintering methods. Heat treatments were conducted in air at 873 K for 0-480 h. The surface oxidation was investigated by bulk surface X-ray diffraction (XRD) measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The Seebeck coefficient and the electrical conductivity of samples were measured before and after heat treatments. XRD, SEM, EDS, and XPS results revealed that the clathrate phase near the surface was changed to Al-poor clathrate phases and an oxide phase (probably barium aluminate: BaAl2O4). However, the thermoelectric properties of samples were almost unchanged by the heat treatment in air at 873 K for up to 480 h because the chemical composition of the inner part of sample was almost stable.

scholarly journals Fabrication of Ba Doped LaMnO3 Nanomaterials by Microwave Combustion Method

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Nguyen Viet Tuyen ◽  
Tran Thi Ha ◽  
Pham Nguyen Hai ◽  
Tran Thi Uyen ◽  
Nguyen Ngoc Dinh ◽  
...  
Keyword(s):  
Fossil Fuel ◽  
Hexagonal Phase ◽  
Cost Effective ◽  
Combustion Method ◽  
Diffraction Measurement ◽  
Time Saving ◽  
X Ray ◽  
Microwave Combustion ◽  
Doping Ratio ◽  
Microwave Combustion Method

The major energy sources that human are relying on are fossil fuel and it is exhausted day by day. Furthermore, exploition and usage of fossil fuel also bring in many negative impacts on environmental polution. Solid oxide fuel cell (SOFC) has been considerred as a potential solution for such environmental and energy problems. Seeking a facile, cost and time saving process to synthesize Ba doped LaMnO3 is very important for development of SOFC applications because it helps to reduce the cost of comercial SOFC. LaMnO3 doped with Ba is more cost effective than Sr doped LaMnO3 because less rare earth elements are used. At the same time, its conductivity is still good enough with an appropriate thermal expansion matched with those of other parts of SOFC based on ytrium stabilized zirconia (YSZ). In this paper, Ba doped LaMnO3 nanoparticles (LBMO), a promissing material for making cathode of SOFC, were prepared by microwave combustion method. This material has many advantages.  Effect of the amount fuel in the combustion reaction on the products was studied by various methods such as: X-ray diffraction measurement, scanning electron microscopy, energy dispersive X-ray spectroscopy. The results showed that each doping rate requires an appropriate amount of fuel to obtain pure and crystalline product. The obtained LBMO nanoparticles are crystallined in hexagonal phase at doping ratio of 0.2 and orthohombic phase at doping ratio of equal or larger than 0.3.

scholarly journals Design, Development, and Applications of Novel Techniques for Studying Surface Mechanical Properties

1989 ◽  
Vol 153 ◽  
Author(s):  
Kazuhisa Miyoshi
Keyword(s):  
Surface Chemistry ◽  
Photoelectron Spectroscopy ◽  
Amorphous Alloys ◽  
Surface Segregation ◽  
Metallic Materials ◽  
Design Development ◽  
X Ray ◽  
Structure Surface ◽  
Properties Of Materials ◽  
Adhesion Friction

AbstractThis paper reviews the author's research of the adhesion, friction, and micromechanical properties of materials and presents examples of the results. The ceramic and metallic materials studied include silicon carbide, aluminum oxide, and iron-base amorphous alloys. The design and operation of a torsion balance adapted for study of adhesion from the Cavendish balance are discussed first. The pull-off force (adhesion) and shear force (friction) required to break the interfacial junctions between contacting surfaces of the materials were examined at various temperatures in a vacuum. The surface chemistry of the materials was analyzed by x-ray photoelectron spectroscopy. Properties and environmental conditions of the surface regions which affect adhesion and friction - such as surface segregation, composition, crystal structure, surface chemistry, and temperature were also studied.

Two dimensional Sr silicate grown on Si(001) studied using X-ray Photoelectron Spectroscopy

2006 ◽  
Vol 132 ◽  
pp. 87-90
Author(s):  
M. El Kazzi ◽  
G. Delhaye ◽  
S. Gaillard ◽  
E. Bergignat ◽  
G. Hollinger
Keyword(s):  
Photoelectron Spectroscopy ◽  
Two Dimensional ◽  
X Ray
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