Effect of Gold Particle Size and Deposition Method on the Photodegradation of 4-Chlorophenol by Au/TiO2

Abstract

The photoactivity of TiO2 P25 modified by surface-deposition of gold nanoparticles was investigated trough the photocatalytic degradation of aqueous 4-Chlorophenol (4-CP). The Au/TiO2 materials were prepared by three methods: photodeposition, deposition–precipitation (D–P) and colloidal deposition. Each preparation yields to different particle size, distribution and properties of gold nanoparticles. However, the photoactivity of these systems depends mainly on the gold particle size. All the materials fit well to a pseudo first order rate model and a relationship between the kinetic rate and the resulting particle sizes was found, which shows the importance of the nanoparticle size in the photoactivity of the TiO2 modified by gold. The optimal load was found to be 0.5 wt% Au/TiO2 for the material prepared by D–P, since this material increased the photoactivity degradation of commercial TiO2 in 80%.