Photocatalytic activity and electrochemical response of titania film with macro/mesoporous texture

Multifunctional anatase titania (TiO2) films with macro/mesoporous texture have been prepared using a non-acidic polyethylene glycolassociated titanium alkoxide precursor sol, followed by 500 degrees C calcination. It was found that increasing polyethylene glycol 2000 loading in the sol not only increases the macroporous size in the films, but can also lead to an enhancement of mesopore volume (the number of mesopores). This is considered to have major contribution to increasing the final specific surface area due to inhibition of pore shrinkage or collapse at high calcination temperature (i.e., 500 degrees C). Good dissolution of polyethylene glycol 2000/acetonitrile solution in the isopropanol based sol can lead to the formation of the resulting TiO2 films with uniform and macroporous surface morphology. The film at optimum polyethylene glycol loading (20 g/L polyethylene glycol 2000, 500 degrees C) exhibits good mechanical stability, enhanced photocatalytic activity in the degradation of 2,4-dichlorophenol in water and superior electrochemical response to catechol in the presence of ascorbic acid (a common interferent) by cyclic voltammetry. The unique textural structure, including enhanced specific surface area/pore volume and macroporous morphology with mesoporous anatase titania wall (average macrospore size in the range of 150-200 nm, mesoporous size of similar to 5 nm) are considered to be the main factor attributing to such a multifunction of the titania films. (C) 2008 Elsevier B.V. All rights reserved.