The Syntheses, Characterizations, and Photocatalytic Activities of Silver, Platinum, and Gold Doped TiO2Nanoparticles

Abstract

Different weight percentages of Ag, Pt, and Au doped nano TiO₂ were synthesized using the acetic acid hydrolyzed sol-gel method. The crystallite phase, surface morphology combined with elemental composition and light absorption properties of the doped nano TiO₂ were comprehensively examined using X-ray diffraction (XRD), N2 sorption analysis, transmission electron microscopic (TEM), energy dispersive X-ray, and DRS UV-vis analysis. The doping of noble metals stabilized the anatase phase, without conversion to rutile phase. The formation of gold nano particles in Au doped nano TiO₂ was confirmed from the XRD patterns for gold. The specific surface area was found to be in the range 50 to 85 m2/g. TEM images confirmed the formation a hexagonal plate like morphology of nano TiO₂. The photocatalytic activity of doped nano TiO₂ was evaluated using 4-chlorophenol as the model pollutant. Au doped (0.5 wt %) nano TiO₂ was found to exhibit higher photocatalytic activity than the other noble metal doped nano TiO₂, pure nano TiO₂ and commercial TiO₂ (Degussa P-25). This enhanced photocatalytic activity was due to the cathodic influence of gold in suppressing the electron-hole recombination during the reaction.