CL : Vol. 36 (2007) , No. 3 p.348

Applications of Single-site Photocatalysts Implanted within the Silica Matrixes of Zeolite and Mesoporous Silica

1) Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University
2) Research Center for Solar Energy Chemistry, Osaka University

(Received November 6, 2006)

The tetrahedrally coordinated metal oxide (titanium, vanadium, chromium, and molybdenum oxides) moieties can be implanted and isolated in the silica matrixes of microporous zeolite and mesoporous silica materials and named as “single-site photocatalysts.” Under UV-light irradiation these single-site photocatalysts form the charge-transfer excited state, i.e., the excited electron–hole pair state which localizes quite near to each other as compared to the electron and hole produced in semiconducting materials, plays a significant role in various photocatalytic reactions. Especially, the single-site titanium oxide photocatalyst demonstrates the high reactivity and selectivity under UV-light irradiation, while the single-site chromium oxide operates as a visible-light sensitive photocatalyst. These single-site photocatalysts not only can promote photocatalytic reactions but also can be utilized to synthesis of functional materials. The transparent mesoporous thin film with single-site photocatalyst generates the superhydrophilic surface. The nano-sized metal catalyst can be photodeposited on the excited single-site photocatalyst under UV-light irradiation.