銀ナノシートを用いた酸化チタン非接触光触媒活性の評価

Remote photocatalytic reaction of a Pt-modified TiO<SUB>2</SUB> thin film was investigated by using Ag nanosheet as a marker. The Ag nanosheet is a two-dimensional crystalline film composed of myristate-capped silver nanoparticles (d = 5 nm), which has a strong localized plasmon absorption band at <I>λ</I><SUB>max</SUB> = 470 nm. The Ag nanosheet on a 50 nm gold film was set on a measurement cell at 10 μm distance from the Pt-modified TiO<SUB>2</SUB> film. Then the refractive index change of Ag nanosheet was real-time monitored by a surface plasmon resonance (SPR) technique under UV light irradiation (wavelength: 365 nm) from the back side of the TiO<SUB>2</SUB> film. The plasmon resonance angle shifted to lower angle in consequence of the degradation of Ag nanosheet due to the remote photocatalytic reaction. We found the reaction was continued even after stopping UV irradiation, i.e., a chain reaction in Ag nanosheet was suggested. The chain reaction was influenced by N<SUB>2</SUB> gas purge as well as the ligand exchange of myristate capping molecules to alkyl thiolate.