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Chemical state
About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.
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TL;DR: In this paper, the results of test measurements using EDIXS for chemical characterization implemented in a conventional x-ray tube based laboratory were presented, suggesting the real possibility of rutinary chemical state characterizations of samples by means of EDIXs using conventional xray tube.
Abstract: Energy Dispersive Inelastic X-ray Scattering (EDIXS) is a reliable technique for the discrimination and characterization of local chemical environments. By means of this methodology, the speciation of samples has been attained in a variety of samples and experimental conditions, such as total reflection, grazing incidence, and confocal setups. Until now, due to the requirement of a monochromatic and intense exciting beam, this tool had been applied using exclusively synchrotron radiation sources. We present, for the first time, results of test measurements using EDIXS for chemical characterization implemented in a conventional x-ray tube based laboratory. The results show good discrimination between different iron compounds under study, suggesting the real possibility of rutinary chemical state characterizations of samples by means of EDIXS using a conventional x-ray tube.
TL;DR: In this article, the chemical state of the sulfur in platinum/carbon electrocatalysts has been examined by measuring its oxidation state via x-ray photoelectron spectroscopy at different points during the preparation of a mock fuel-cell electrode.
Abstract: Vulcan carbon is the favored support for fuel-cell electrocatalysts, but as-received it contains high levels of sulfur (ca. 5000 ppm or greater) which could potentially poison the fuel-cell electrochemistry. The chemical state of the sulfur in platinum/carbon electrocatalysts has been examined by measuring its oxidation state via x-ray photoelectron spectroscopy at different points during the preparation of a mock fuel-cell electrode. Also monitored were the presence of sulfate in the aqueous wash from the electrocatalysts and the cyclic voltammetry of the electrocatalysts after each preparation step. Our studies indicate that the platinum catalytically oxidizes some of the covalent sulfur in the vulcan carbon to sulfate when water, heat, and strong physical contact between Pt and C are all present. These conditions are attained during the preparation of typical fuel-cell electrodes. Most of the zero-valent sulfur remains in the carbon after treatment, however, and appears not to be initially in contact with the Pt. This remaining unoxidized sulfur may be a source of poisoning to the Pt electrocatalyst with long-term electrochemical use, particularly at the fuel-cell cathode.
22 Oct 1995
TL;DR: In this paper, the loss and recovery of hydrophobicity on silicone rubber surfaces during different plasma treatments and following storage at ambient atmosphere are presented. But the results of the experiments were limited to the case where the plasma gases were oxygen, air, nitrogen and argon.
Abstract: Studies of the loss and recovery of hydrophobicity on silicone rubber surfaces during different plasma treatments and following storage at ambient atmosphere are presented. The plasma gases were oxygen, air, nitrogen and argon. Attempts were made to understand correlation between the chemical state of surface, its hydrophobicity and plasma nature. The changes in the chemical state were investigated by means of chemiluminescence, infrared and differential scanning spectroscopic methods.
Patent•
06 Jun 2013
TL;DR: In this paper, the authors proposed a quantitative evaluation method of surface chemical state of a conductive material, which can quantitatively evaluate the surface chemical states even when an inner shell spectrum has an asymmetric peak shape in a chemical state analysis using the XPS method.
Abstract: PROBLEM TO BE SOLVED: To provide a quantitative evaluation method of surface chemical state of a conductive material, which can quantitatively evaluate the surface chemical state even when an inner shell spectrum has an asymmetric peak shape in a chemical state analysis using the XPS methodSOLUTION: The quantitative evaluation method of the conductive material surface comprises: a first step of displaying, in an X-Y coordinate, each of two or more inner shell spectra having different structures of a conductive material of which a surface is not subject to functional group modification treatment, by the XPS method; a second step of dividing the inner shell spectra into two or more symmetric functions of the X-Y coordinate so as to fit to all inner shell spectra of the inner shell spectra displayed in the X-Y coordinate by the first step, and defining an asymmetric peak function displayed in the X-Y coordinate by the sum of the two or more symmetric functions; and a third step of dividing the asymmetric peak of the conductive material to be measured by using the asymmetric peak function defined by the second step, and calculating the sum of areas of the X-Y coordinate of the peak functions as an asymmetric peak area