Synthesis and Characterization of Bi/TiO₂, V/TiO₂, and Bi-V/TiO₂ Nano-Sized Particles

抄録

This study was focused on the super-hydrophilicity of anatase TiO₂ including metals with three-oxidation state and five-oxidation state. The nanometer-sized TiO₂s including Bi³⁺, V⁵⁺, and Bi³⁺/V⁵⁺ ions were prepared using a solvothermal method. The XRD result identified these to have pure anatase structures after solvothermal treatment at 200°C for 10 h without any treatment. The calcination was done to remove impurities on surface and to have higher crystallization at 500°C for 3 h. The spherical particle sizes were distributed in the range of 10-50 nm after calcination. In the case of sample including Bi component, the particle size more decreased than pure TiO₂, while it increased in sample with V component. The surface areas also more increased in Bi/TiO₂ and more decreased in V/TiO₂ compared to pure anatase TiO₂. The XPS result showed that the peaks for O1s (Ti-O) were shifted to larger binding energy in Bi/TiO₂, but it was shifted to smaller binding energy in V/TiO₂. In particular, the peak assigned to Ti-OH decreased with Bi component amount, however, it increased with V component amount. The photoluminescence intensity, which contributed to emitted electrons, decreased in the order TiO₂, Bi/TiO₂, and finally V/TiO₂. The contact angles had about 3 - 5° on Bi/TiO₂ nano-sized film (thickness 200 nm) even though after irradiation for 2 h, however it approached to 0° with V component addition after 20 min.