Structure analysis for visible light photocatalytic titanium dioxide by using small-angle scattering

Yamaguchi, Daisuke; Noda, Yohei; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*

The structure of nitrogen (N)-doped titanium dioxide (TiO), which is a visible light photocatalyst, was investigated by small-angle neutron (SANS) and X-ray scattering (SAXS) methods. The bare TiO was fabricated by sol-gel method and possessed a characteristic length of ca. 10 nm due to some regularity consisting of TiO particles and pores. In the air, bare TiO and N-doped TiO specimens showed a similar scattering profiles each other for both of SANS and SAXS measurements. A slight increase of scattering intensity was observed for N-doped TiO specimen only on the SANS profile. To confirm whether the slight difference in SANS profiles between bare TiO2 and N-doped TiO specimens was due to the doped N atoms, both of bare TiO and N-doped TiO specimens were soaked in the mixture of HO/DO = 55/45 (w/w) mixture, of which scattering contrast for neutron is the same as TiO, and measured by SANS. The resultant SANS profiles of soaked bare TiO and N-doped TiO specimens were distinctly different each other and the scattering from doped N atoms, which gives the information of their distribution was captured.