Photocatalytic Properties of Porous Metal Oxide Networks Formed by Nanoparticle Infiltration in a Polymer Gel Template

Abstract

The infiltration of preformed nanoparticles in a porous polymer gel template for the formation of inorganic networks retaining high porosity is described. The use of a number of metal oxide sols including titania, zirconia, and indium oxide, and mixtures of TiO2/ZrO2 and TiO2/In2O3, resulted in structures that demonstrated templating of the initial organic gel. The final networks were homogeneously porous and had significant surface areas of up to 65 m2 g-1. The wall thickness of the inorganic structure and the surface area, along with the final amount of inorganic material that infiltrated the polymer gel, were found to be dependent on the metal oxide being considered. Photocatalytic studies of the titania-containing networks were monitored by the degradation of 2-chlorophenol and compared with the reference titania photocatalyst, Degussa P25. The titania network was about 20% more active than the standard and the mixed metal oxides showed higher activity again (up to 80% more active than the Degussa P25 sample). The addition of the second metal oxide to the titania decreased the amount of the rutile crystalline phase in the final structure and increased the network surface area, both of these changes are considered positive for enhancement of the photocatalytic activity.