1. Introduction
Photocatalytic technologies for environmental purification have been developed to eliminate refractory organic contaminants [1] and [2]. Yet, the use of aqueous suspensions of photocatalysts in practical applications is limited, because they require separation following treatment. Considerable work has been performed to develop immobilized TiO2 catalysts on various substrates, such as thin films and membranes, for use in many applications [3]. The photocatalytic activity of immobilized TiO2, however, is low due to exfoliation of the deposited TiO2 thin film and to reductions in the effective surface area that is to be illuminated [4].