Noble metal-modified porous titania networks and their application as photocatalysts

In order to enhance the photocatalytic activity of titania materials, which suffer from high percentages of photon-induced electron and hole pair recombination, noble metal (Pd, Au, Ag, and Pt) modified porous titania materials were prepared. A modified deposition precipitation technique was used to deposit the metal onto a porous TiO 2 support preformed using an agarose gel templating technique coupled with sol-gel chemistry. The final composites were characterized by use of SEM-EDX, TEM, XRD, diffuse reflectance UV/Vis spectroscopy, X-ray photoelectron spectroscopy, FTIR, inductively coupled plasma mass spectroscopy, zeta potential, and secondary ion mass spectrometry. The photocatalytic activity of the samples was investigated by monitoring changes in methylene blue concentration under UV light irradiation. The photocatalytic activity was enhanced significantly, relative to the pure titania support, by Pd (63%) and Au (31-37%), and slightly by Ag (24%) and Pt (12%) at the respective optimum metal deposition amount. A uniform distribution of metal in the TiO 2 network, the metallic form of the noble metal, and an increased organic pollutant adsorption contributed positively to the photocatalytic activity of the final materials.