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 incorporate d in the bicontinuous polymer structure where hydrolysis and condensation r eactions were carried out, producing a hybrid of polymer and amorphous tita nia. Calcination of this hybrid resulted in the formation of a continuous, purely inorganic network of either the anatase or rutile crystal phase, wit h the individual titanium dioxide particles contacting a number of neighbor s, thereby forming a continuous three-dimensional structure. The resulting networks have vastly different structures, with porosities as high as 99% a nd 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 ph otocatalysis, because the open "coral-like" network structure of the titani um dioxide allows high access of the titanium dioxide surface to the reacti on medium. The potential of the gel coating technology for the construction of more complex chemical systems was illustrated by the assembling of a no ble 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 photocataly tic activity of Degussa P25.