An aqueous sol-gel route to synthesize nanosized lanthanadoped titania having an increased anatase phase stability for photocatalytic application

A novel synthesis method is reported, involving peptisation and doping of lanthana on colloidal sol-gel titania derived from titanyl sulphate, where the anatase phase has a high stability above 800degreesC and a specific surface area of 101 m(2) g(-1) for the gel calcined at 500degreesC. The undoped gel calcined at 600degreesC has an average crystallite size of 12 nm, but under identical experimental conditions, the doped one shows an average crystallite size of 7 nm. The doped titanium oxide has a specific surface area of 25 m(2) g(-1) even after calcination at 800degreesC. The exceptionally high phase stability and surface area are due to the specific synthesis method. Doped titania also shows an excellent photoactivity as evaluated by the extent of decomposition of methylene blue when exposed to ultraviolet light. (C) 2004 Elsevier B.V. All rights reserved.