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.