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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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01 Sep 2022
TL;DR: In this paper , the role of X-ray absorption spectroscopy (XAS) in determining the oxidation state, chemical fraction, and local atomic structure of the materials was discussed by taking LiNiO2 and Mn3O4 as prototype materials.
Abstract: This work discussed the role of X-ray absorption spectroscopy (XAS) in determining the oxidation state, chemical fraction, and local atomic structure of the materials. These aspects of XAS were discussed by taking LiNiO2 and Mn3O4 as prototype materials. The oxidation state of metal ions in these oxides was estimated with the help of XAS spectra of the reference oxides such as NiO (in the case of LiNiO2), MnO, Mn2O3, and MnO2 (in the case of Mn3O4). Analysis of the oxidation state was performed from the main absorption edge which was estimated from half of the step height. This showed that the Ni K-edge absorption edge of LiNiO2 is slightly above that of NiO. In the case of Mn ions, the main absorption edges show a linear variation with the oxidation states. This estimates the presence of a mixed oxidation state (2.6+) of Mn ions in Mn3O4. Linear combination fitting results exhibit that almost 35% of ions are in a 2+ oxidation state. The remaining ions are in a 3+ oxidation state. Thus, XAS can determine the fractions of each oxidation state of a particular ion in a given material. Quantitative information on coordination number and bond distance of nearest neighbor for a given element of a material is another important use of this technique.
TL;DR: In this article , the authors demonstrate on the example of Si-doped Fe2O3, how thin films can be effectively utilized as a model system to facilitate systematic investigation of the solid-state reduction behavior.
TL;DR: In this paper, the authors presented an extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 - August 2, 2012.
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.
05 Sep 2018
TL;DR: In this article, the existence of amide component, protein functional groups dissociated to active protein moieties and attached to titanium dioxide surface in form of hybrid nanomaterial were characterized by Fourier transform infrared spectroscopy (FT-IR).
Abstract: Keratin modification on surface of titanium dioxide P25 was carried out from titanium dioxide suspension and keratin solution extracted from swine wool. The existence of amide component, protein functional groups dissociated to active protein moieties and attached to titanium dioxide surface in form of hybrid nanomaterial were characterized by Fourier-transform infrared spectroscopy (FT-IR). The keratin protein decorated on particle surfaces was observed by Field Emission Scanning Electron Microscopy (FESEM). Chemical states and bonding at the nano-biomolecule interfaces with titanium dioxide were investigated using X-ray Photoelectron Spectroscopy (XPS). Protein concentration is considered as roles for protein modification, surface bonding, chemical states and protein adsorption. The Ti3+ and Ti2+ surface and high adsorption degree can be obtained at low concentration of protein solution with P25. However, the strong bonding between protein and TiO2 obtained in high protein concentration with Ti3+ and Ti2+ species result disappear for Ti3+ and Ti2+ XPS peaks. The adsorbed protein reveals secondary structure of random coil keratin with strong bonding conjugated to the titanium dioxide surface. The strong binding between protein and TiO2 surface in this novel protein-TiO2 hybrid material shows a promising alternative way for advance tunable electronic structure and charge transport mechanism which enhance electrochemical capacitance by mean of double layer and pseudo-capacitive behavior.