Surface Structure and Photocatalytic Activity of Ti Supported on Alumina Powder [Translated]†

Abstract

Surface modified alumina powder that has photocatalytic activity was studied. To control the amount of Ti introduced on the surface at the molecular level, the powder was prepared by chemical surface modification with a monofunctional titanate-based coupling agent, followed by partial oxidation of the modification group. The surface density of Ti introduced onto the surface was quantitatively increased with the concentration of the modifying reagent, and/or repetition of the modification. Furthermore, the relationship between the surface structure and the occurrence of photocatalytic activity was examined. The surface structure was measured by XPS and UV-Visible absorption spectrometry. The photocatalytic activity was determined by measuring the degradation of Methylene Blue molecules in water solution with UV irradiation. Photocatalytic activity was realized at a Ti surface density of 3.7 nm–2. The optical absorption edge in UV of the sample shifted to longer wavelengths. The ability as a photocatalyst increased with the amount of Ti-O-Ti. Photocatalytic activity was recognized to be related to the amount of Ti-O-Ti on the alumina surface and the ability of UV absorption.† This report was originally printed in J. Soc. Powder Technology, Japan 39, 102-107 (2002) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.

Keywords

• alumina powder
• photocatalyst
• photodegradation
• surface modification
• titanate-based coupling agent