Thursday, November 5, 2009: 12:20 PM
Brahma (Camino Real Hotel)
Photoreduction of ionic platinum or gold into metallic nanoparticles on the surface of new metal oxide materials was done from aqueous solutions of the metal salts, in an effort to investigate the photo activity and electronic characteristics of the oxides. The new materials are being developed as photocatalysts for photochemical solar energy conversion. In this study, KTiNbO5 and KNb3O8 were used as starting compounds, and colloids were derived via their chemical exfoliation. The colloids consist of individual lamellar particles that retain their crystallinity from the parent compounds. The colloids were agglomerated into highly porous framework solids. The resulting materials have a random pore size distribution. The synthesis provided a low temperature route to stable polycrystalline materials. The crystalline properties of the new photocatalysts are expected to provide good electronic conductivity. Metal quantification, electron microscopy, X-ray diffraction, X-ray fluorescence, nitrogen adsorption surface area analysis, and optical absorbance measurements were done to characterize the porous substrates and the metallic deposits.