Previously we developed a novel alumina sol composed of uniform fibrous nanoparticles. It has unique physical properties. It can be painted on devices. A self-supporting transparent film can be made with this sol, as well. Therefore, it is a very unique and promising material as a substrate of catalysts. It is possible to dope metal species into this alumina sol. Among them, a Tb doped alumina film showed luminescent properties after calcination treatment. Since the photoluminescent (PL) performance sensitively reflects the local environment around Tb, we tried to find out the PL active structure with X-ray absorption fine structure (XAFS) analysis. Since the PL performance changed with the calcination temperature, combined in situ XAFS and X-ray diffraction (XRD) analysis was applied to the Tb doped alumina during the pretreatment process. According to the Tb L<sub>III</sub>-edge XAFS results, the Tb atom remained as a trivalent ion. However, the structure around Tb started to change at 423 K, which was confirmed by XANES. On the other hand, decrease in XRD peaks due to a phase transition started at 623 K. Since the structural change around Tb and alumina phase transformation occurred consecutively, it was suggested Tb was not incorporated into the framework of alumina but was atomically dispersed on the surface of alumina. The most PL active structure was atomically dispersed Tb ions firmly bound to gamma-alumina through oxygen atoms.

Combined, <i>in situ</i> XAFS and XRD study of terbium-doped fibrous alumina

251st National Meeting (2016)

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Combined, in situ XAFS and XRD study of terbium-doped fibrous alumina