Modification of TiO2 network structures using a polymer gel coating technique

A variety of polymer gels with different chemical composition, architecture, porosity, and surface area have been used as templating materials for the fabrication of porous TiO2 networks. Titanium isopropoxide was incorporated in the bicontinuous polymer structure where hydrolysis and condensation reactions were carried out, producing a hybrid of polymer and amorphous titania. Calcination of this hybrid resulted in the formation of a continuous, purely inorganic network of either the anatase or rutile crystal phase, with the individual titanium dioxide particles contacting a number of neighbors, thereby forming a continuous three-dimensional structure. The resulting networks have vastly different structures, with porosities as high as 99% and surface areas ranging from 5 to 100 m(2) g(-1). These structures may be of importance to various fields of research, including photovoltaics and photocatalysis, because the open coral-like network structure of the titanium dioxide allows high access of the titanium dioxide surface to the reaction medium. The potential of the gel coating technology for the construction of more complex chemical systems was illustrated by the assembling of a noble metal/oxide semiconductor hybrid where homogeneously dispersed platinum nanoparticles are integrated within the TiO2 network. Preliminary studies have shown the titanium dioxide materials to exhibit 75% of the photocatalytic activity of Degussa P25.