A review on catalytic applications of Au/TiO2 nanoparticles in the removal of water pollutant.

Nanomaterials are showing great potential for the improvement of water treatment technologies. In recent years, catalysis and photocatalysis processes using gold nanoparticles (Au-NPs) have received great attention due to their effectiveness in degrading and mineralizing organic compounds. This paper aims to review and summarize the recently published works and R & D progress in the field of photocatalytic oxidation of various water pollutants such as toxic organic compounds (i.e. azo dyes and phenols) by Au-NPs/TiO2 under solar, visible and UV irradiation. Extensive research which has focused on the enhancement of photocatalysis by modification of TiO2 employing Au-NPs is also reviewed. Moreover, the effects of various operating parameters on the photocatalytic activity of these catalysts, such as size and loading amount of Au-NPs, pH and calcination, are discussed. The support type, loading amount and particle size of deposited Au-NPs are the most important parameters for Au/TiO2 catalytic activity. Our study showed in particular that the modification of TiO2, including semiconductor coupling, can increase the photoactivity of Au/TiO2. In contrast, doping large gold NPs can mask or block the TiO2 active sites, reducing photocatalytic activity. The optimized loading amount of Au-NP varied for each experimental condition. Finally, research trends and prospects for the future are briefly discussed.