Topic
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, XPS studies were conducted on the ZrCr2.6 surface of a ZRCr2H3.6 and showed that it contains Cr2O3, Cr(O), Zr2O and nonstoichiometric ZrO2−x.
Abstract: According to XPS studies, the ZrCr2 and ZrCr2H3.6 surface have been established to contain Cr2O3, Cr(O), Zr2O and nonstoichiometric ZrO2−x. The Cr(O) content increases after thermal vacuum treatment of the samples, particularly after Ar+ sputtering. Active hydrogen evolving from the hydride lattice also promotes the increase in the Cr(O) content. After oxidation, chromium is detected only as Cr2O3.
3 citations
Journal Article•
TL;DR: In this article, a soft X-ray emission spectroscopy was used to obtain ultra-high-energy-resolution spectra of Li-K and O-K for three critical Li compounds.
Abstract: Lithium metal and lithium oxides are components of lithium–oxygen (Li–O₂) batteries. To accurately identify Li compounds and understand the degradation mechanism, fundamental knowledge of the electron structures of constituent elements is vital. However, experimentally derived occupied states of Li have been missing due to the intrinsic difficulties in their detection. Herein, using soft X-ray emission spectroscopy, ultrahigh-energy-resolution spectra of Li–K were collected for three critical Li compounds: Li, Li₂O₂, and Li₂O. Large chemical shifts to lower energies and peak broadening were observed in compound-specific Li–K and O–K spectra. Theoretical calculations confirm that these changes derive from the characteristic electronic configurations of 1s and 2p states with core-level shifts in Li⁺. The large chemical shift (∼4.6 eV) between the Li and Li₂O peaks was utilized to visualize the chemical state mapping of the Li metal/oxide phase, facilitating the identification of chemical phases in Li compounds.
3 citations
07 Nov 2014
TL;DR: In this article, X-ray excited Pu core-valence-vence and core-core-ventsence Auger line-shapes were used in combination with the Pu 4f photoelectron peaks to characterize differences in the oxidation state and local electronic structure for Pu compounds.
Abstract: X-ray excited Pu core–valence–valence and core–core–valence Auger line-shapes were used in combination with the Pu 4f photoelectron peaks to characterize differences in the oxidation state and local electronic structure for Pu compounds. The evolution of the Pu 4f core-level chemical shift as a function of sputtering depth profiling and hydrogen exposure at ambient temperature was quantified. The combination of the core–valence–valence Auger peak energies with the associated chemical shift of the Pu 4f photoelectron line defines the Auger parameter and results in a reliable method for definitively determining oxidation states independent of binding energy calibration. Results show that PuO2, Pu2O3, PuH2.7, and Pu have definitive Auger line-shapes. These data were used to produce a chemical state (Wagner) plot for select plutonium oxides. This Wagner plot allowed us to distinguish between the trivalent hydride and the trivalent oxide, which cannot be differentiated by the Pu 4f binding energy alone.
3 citations
TL;DR: In this article, the crystal orientation and the morphology of nanostructure of annealed samples were investigated, which revealed that CuFe1-xNixO2 samples are hexagonal delafossite structure and the average grain size is 0.258-0.760 µm.
3 citations
TL;DR: The high-resolution XPS C 1s data indicate that new chemical states of carbon form as the F is removed and that the relative amounts of these states depend on the F content of the near-surface region.
Abstract: In this study the chemical alterations of poly(tetrafluoroethylene) (TFE Teflon) by approximately 1.0-keV electrons and 1.0-keV He and Ar ions have been examined using X-ray photoelectron spectroscopy (XPS). The initial F/C atom ratio of 1.99 decreases to a steady-state value of 1.48 after 48 h of electron exposure. Exposure to either He+ or Ar+ decreases the initial F/C atom ratio from approximately 2 to a steady-state value of 1.12. The high-resolution XPS C 1s data indicate that new chemical states of carbon form as the F is removed and that the relative amounts of these states depend on the F content of the near-surface region. These states are most likely due to C bonded only to one F atom, C bonded only to other C atoms and C that have lost a pair of electrons through emission of F-. Exposures of the electron-damaged and He+- or Ar+-damaged surfaces to research-grade O2 result in chemisorption of very small amounts of O indicating that large quantities of reactive sites are not formed during the chemical erosion. Further exposure to the electron or ion fluxes quickly removes this chemisorbed oxygen. Exposure of the He+-damaged surface to air at room temperature results in the chemisorption of a larger amount of O than the O2 exposure but no N is adsorbed. The chemical alterations due to electrons and ions are compared with those caused by hyperthermal (approximately 5 eV) atomic oxygen (AO) and vacuum ultraviolet (VUV) radiation. The largest amount of damage is caused by AO followed by VUV, inert-gas ions, and then electrons.
3 citations