Novel accumulation of photo-induced MV+* embedded in a TiO2 shell and discharge of electrons to a Pt electrode.

After UV-irradiation of a TiO(2) shell on Pt anode was cut off, anodic current was observed continuously for some time because long-lived MV(+)* produced from MV(2+) embedded inside the shell, as a result of the electron transfer from the conduction band of the irradiated TiO(2) shell, diffused slowly and discharged to the shell thus realizing electron accumulation inside the TiO(2) shell.

Direct detection of a phase change in PdO/CeO2 supported on chi-Al2O3 by means of in situ high-temperature measurements of XRD and FTIR.

Phase changes between PdO and Pd metal can be directly detected in PdO/CeO2 catalysts supported on chi-Al2O3 by means of in situ high-temperature measurements of X-ray diffraction and FT-IR in relation to the catalytic activity for the methane oxidation of microcrystalline PdO. Reversible changes in the solid phases are observed from PdO to Pd and Pd to PdO under O2-deficient and O2-excess atmospheres, respectively. Nanosizes of PdO and Pd crystallites, the distorted PdO crystal structure along the (110) plane, and also a distorted Pd metal crystal structure along the (200) plane as well as the large surface area elucidate the high catalytic activity for the methane oxidation of PdO/CeO2 catalysts prepared with an atomic ratio of Pd:Ce = 1:1.