Characterization of the local structures of Ti-MCM-41 and their photocatalytic reactivity for the decomposition of NO into N2 and O2.
Ti-MCM-41 mesoporous molecular sieves were prepared at ambient temperature and were characterized by X-ray absorption near-edge structure and extended X-ray absorption fine structure, UV-vis, Fourier transform infrared spectroscopy, and photoluminescence spectroscopic analyses. It was found that an increase in the Ti content caused the structure of the Ti-oxides in Ti-MCM-41 to change from an isolated tetrahedral coordination to adjacent Ti-oxide species with Ti4+ of tetrahedral coordination. The photocatalytic reactivity of these catalysts for the decomposition of NO into N2 and O2 was found to strongly depend on the local structure of the Ti-oxide species including their coordination and distribution, i.e., the charge transfer excited state of the highly dispersed isolated tetrahedrally coordinated Ti-oxides act as the active sites for the photocatalytic decomposition of NO into N2 and O2.
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
Yun
Y
Hu
Gianmario
G
Martra
Jinlong
J
Zhang
Shinya
S
Higashimoto
Salvatore
S
Coluccia
Masakazu
M
Anpo