Ultrahighly Dispersed Titanium Oxide on Silica : Effect of Precursors on the Structure and Photocatalysis S. Yoshida, S. Takenaka, T. Tanaka et T. Funabiki J. Phys. IV France, 7 C2 (1997) C2-859-C2-861 DOI: 10.1051/jp4:1997259