Papers by Author: Michihiro Miyake

Abstract: The crystal structure and oxide ion conduction properties of La0.9Sr0.1Ga0.9Mg0.1O2.9 were compared with those of LaGa0.8Mg0.2O2.9 with the same oxygen vacancy concentration. Although La0.9Sr0.1Ga0.9Mg0.1O2.9 had a smaller free space through which oxide ions pass compared to LaGa0.8Mg0.2O2.9, the activation energy of oxide ion conduction in the former was lower. This was attributed to the large displacement of La and Ga in La0.9Sr0.1Ga0.9Mg0.1O2.9. The GaO6 octahedral tilts in the LaGaO3 perovskite structure were reduced by double doping with Sr and Mg. Reduction of the GaO6 octahedral tilt proved effective for oxide ion conduction.

Abstract: Recovery process of Ni from anode materials of spent Ni-MH batteries and application of the resulting Ni to CH4 dry reforming catalyst were investigated, focusing on availability of Ni. NiO, which formed a solid solution with CoO, was successfully prepared from the waste by a series of chemical processes using aqueous solutions of HCl and NH3. The resulting NiO, which was reduced to Ni0, exhibited excellent CH4 conversion in CH4 dry reforming. From
results, it was concluded that the Ni recovered from anode materials of spent Ni-MH batteries was available for CH4 dry reforming catalyst.

Abstract: A novel Zr2ON2 catalyst was successfully prepared by nitriding ZrO2, which has a potential enough for H2 formation by the reduction of water under UV irradiation. It was found that the Zr2ON2 had a stable photocatalytic activity for water oxidation and reduction in the presence of sacrificial reagents (methanol or Ag+) under visible light irradiation (λ < 500 nm).

Abstract: Doping effects of Sr and/or Mg on the crystal structures of LaGaO3 perovskites were investigated. The doping with Mg into Ga-site in LaGaO3 led to structural change from the orthorhombic primitive lattice (Pbnm) to the orthorhombic body-centered lattice (Ibmm) at room temperature. The orthorhombic cell (Ibmm) of LaGa0.9Mg0.1O2.95 changed to the monoclinic (I2/a) by doping with Sr into La site. Neutron powder diffraction analyses revealed that these compounds had GaO6 octahedral tilt. The GaO6 octahedral tilt angles were reduced with doping with Sr and/or Mg.