Accession Number : ADA321983

Title :   The Oxidation State of Ni in the Nickel Oxide Electrode and Related Nickel Oxide Compounds: I. Spectroscopic Evidence.

Descriptive Note : Technical rept.,

Corporate Author : GEORGE WASHINGTON UNIV WASHINGTON DC DEPT OF CHEMISTRY

Personal Author(s) : Sambe, H. ; Nabi, T. M. ; Ramaker, D. E. ; Mansour, A. N. ; O'Grady, W. E.

PDF Url : ADA321983

Report Date : JAN 1997

Pagination or Media Count : 21

Abstract : The electronic structures of the nickel oxide electrode, NiO(x)(OH)(2-x) for x=0-1.6, and related nickel oxide materials, Li-substituted NiO, Li(y)Ni(2-y)O2 for y=0-1 and 'Ni(4+)' compounds, KNiO2(IO4) and BaNiO3, have been investigated using Ni 2p XPS (X-ray photoemission spectroscopy) and Ni K-edge XAS (X-ray absorption spectroscopy) data. Three aspects of the Ni 2p XPS spectra (the main peak energy, satellite energy separation, and main-line shape) and three aspects of the Ni K-edge XAS spectra (pre-edge peak energy, K-edge energy at the half-step height, and white-line peak energy) have been analyzed by the aid of simplified models and theoretical calculations. The results of these analyses consistently favor the more covalent electronic structures, Ni(2+)O(-)x(OH)(-)(2-x) X=1.0 AND 1.5, Li(+)Ni(2+)O(1.5-)2, K(+)Ni(2+)O(-)2(IO4)(-) and Ba(2+)Ni(2+)O(1.33-)3, over the conventional ionic electronic structures, Ni(2+x)(+)x(OH)(-)(2-x)X=1.0 AND 1.5, Li(+)Ni(3+)O(2-)2, K(+)Ni(4+)O(2-)2(IO4)(-) and Ba(2+)N(4+)O(2-)3. This finding suggests that the oxidation of the Ni(2+) ion is harder than oxidation of the O(2-) anion for these nickel oxide compounds studied here. p3

Descriptors :   *OXIDATION, *OXIDES, *X RAY PHOTOELECTRON SPECTROSCOPY, *ELECTRODES, *NICKEL COMPOUNDS, PEAK VALUES, COMPUTATIONS, STRUCTURAL PROPERTIES, MATERIALS, COVALENT BONDS, ENERGY, ELECTRONIC EQUIPMENT, SEPARATION, MOLECULAR STRUCTURE, X RAY SPECTROSCOPY, BARIUM, X RAY ABSORPTION ANALYSIS, POTASSIUM.

Subject Categories : Inorganic Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE