Size Control of Titanium Oxide Sheets by Regulating Catalysis in a Catalytic Sol−Gel Process and Their UV Absorption Properties

Catalysis in a sol−gel process of titanium alkoxide was switched off to control the size of sheetlike particles of a resulting titanium oxide. The oxide growth was suspended by adding acetic acid, which regulated the catalytic activity of ammonium acetate. An ultraviolet−visible absorption band depended on the size of sheetlike particles. A lower energy region appeared for the larger size (>1 μm) of sheetlike particles but not for the smaller one. It is probably due to a bridging bidentate of acetate on the flat surface of titanium oxide particles.