Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 121 for “"x-ray absorption spectroscopy"”.
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Chemistry Of Antiwear Films By X-ray Absorption Spectroscopy
… wear. Among the surface techniques employed, X-ray absorption spectroscopy (including EXAFS and XANES) has been mainly used because of its high resolution, low detection limit and non-destructive characteristics.;This is the first time that P and S L-edge XANES spectroscopy has been used to …
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Computational Studies on Bimetallic Catalysis and X-ray Absorption Spectroscopy
… performed on bimetallic catalysis and on X-ray absorption spectroscopy of insulators. The viability of a bimetallic rhodium and cobalt catalysts for industrially important hydroformylation and aldehyde-water shift catalysis (AWS) is discussed. Density functional theory (DFT) studies were …
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X-ray absorption spectroscopy of actinide speciation in solid solutions
… to a wide range of conditions is required. X-ray absorption spectroscopy (XAS), a nondestructive technique that is ideal for determining the molecular composition of materials in dilute quantities in solution and solid forms, was used to determine the speciation of actinides in various solid …
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Comparative Analysis and Speciation of Sulfur K, L-edge X-ray Absorption Spectroscopy
… state ranging from -2 to +6, using K-edge X-ray absorption spectroscopy is particularly useful for determining oxidized species. There are, however, limitations on the ability to visually resolve spectra for reduced and mixed sulfur compounds using the K-edge that may be better resolved using …
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OPERANDO X-RAY ABSORPTION SPECTROSCOPY STUDIES OF (PHOTO)ELECTRODE MATERIALS FOR H2 PRODUCTION/CONVERSION
… (SEM), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. (2) The electrochemical performance, reaction mechanism, charge transfer kinetics, and overpotential of the synthesized electrodes were rigorously …
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Ruthenium K-edge X-ray absorption spectroscopy studies of ruthenium complexes relevant to olefin metathesis
… have been investigated using Ru K-edge X-ray absorption spectroscopy. The lowest energy feature in the Ru K-edge spectrum has been unambiguously assigned as due to Ru 4d←1s transitions. These electric-dipole-forbidden transitions are extremely sensitive to geometry. For centrosymmetric …
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Scanning transmission electron microscopy (STEM) and X-ray absorption spectroscopy (XAS) investigations of catalytic systems
… metal nanoparticles using, predominantly, X-ray absorption spectroscopy (XAS) and scanning transmission electron microscopy (STEM) or spherical aberration-corrected STEM (Cs-STEM). Although the majority of the work focuses on γ-Al2O3 supported nanoparticles because of their industrial …
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Ozone Decomposition and Acetone Oxidation on Manganese Oxide Catalysts
… through various techniques, including x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), Brunauer-Emmett-Teller (BET) surface area analysis, temperature-programmed reduction (TPR), and oxygen chemisorption. The use of these techniques allowed better understanding of the nature …
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Structure and Dynamics in Ligand-Protected and Supported Metal Nanoparticles
This dissertation describes the use of x-ray absorption spectroscopy (XAS) and advanced electron microscopy methods to develop fundamental understandings of nanoparticle structure. Analysis of the x-ray absorption spectra provides structural information with 0.001 A precision. Quantitative …
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Complex Formation of Pb(II) with Cysteine, Penicillamine and N-acetylcysteine
… by 207Pb, 13C, 1H NMR, UV-Vis, ESI-MS, and X-ray absorption spectroscopy. The results of the study provide spectroscopic finger prints for Pb(II) coordination environments relevant to biological systems. The study revealed that small structural changes between each ligand, plays a large role …
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Organocobalt Mediated Cyclizations and Biochemically Inspired Isomerizations - Method Development and Mechanistic Studies.
This dissertation describes research on a wide array of topics. Chapter one follows closelya review publication from our group which details the synthetic and mechanistic progress in the literature from the early to mid-2010s of the Pauson-Khand Reaction(PKR). Chapter two focuses on our work …
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X-RAY CHARACTERIZATION OF PLATINUM GROUP METAL CATALYSTS
… establishing the structure/property link. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are important techniques used for the characterization of PGM catalysts. Microstructural information such as crystallite size, as small as ~ 1 nm, and microstrain can be obtained from …
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Oxygen atom transfer with manganese-exchanged metal-organic frameworks
… whose structure was confirmed by Mn K-edge X-ray absorption spectroscopy. Upon exposure to [superscript t]BuSO₂PhIO, Mn-MOF-5 produces a putative Mn[superscript IV]-oxo intermediate, which upon further reaction with adventitious hydrogen is trapped as a Mn[superscript III]-OH species.
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The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis
… gives insight into growth mechanisms. X-ray absorption spectroscopy measurements are used to characterize catalysts and elucidate the reasons for a support effect in both hydrogenation and oxidations reactions. This investigation aims to produce a more active catalyst by exploring …
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A Theoretical and Experimental Investigation of the Physical and Chemical Properties of Solid Nanoscale Interfaces
… surfaces. Secondly, the detailed analysis of x-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM), x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements will be presented. These investigations will be dedicated to the study of (i) …
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Structural and mechanistic identification of heterogeneous catalysts
… diffuse reflectance infrared Fourier transform spectroscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy may be employed to identify the catalytically relevant properties (charge state, electronic structure, atomic configuration, bonding interaction). Furthermore, this …
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Phosphate and thermal stabilization of heavy metals in dredged sediments
… addition and thermal treatment at 700 C. X- ray absorption spectroscopy (XAS) in combination with principal component analysis, target transformation, and linear combination revealed that in the untreated sediments Zn precipitated as the relatively soluble smithsonite (ZnCO_3) (67%) and …
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A comparative study of PtCo/C Alloys and Pt/C as cathode catalysts for fuel cell applications
… Transmission Electron Microscopy (TEM) and X-ray absorption spectroscopy (XAS).<br/><br/>XAS has also been used to explore the relationship between catalyst activity and structure. This has been achieved by building and validating a specially adapted fuel cell, enabling study of fuel cell …
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