Au-TiO2/SiO2 photocatalysts for building materials: Self-cleaning and de-polluting performance

Abstract

TiO2 is a photocatalytic material that has proven to have the ability to produce self-cleaning and de-polluting building materials, which can be a valuable alternative to mitigate the pollution consequences. However, the TiO2 performance is limited in outdoor conditions due to its exclusive UV absorption. In this work, Au-TiO2 photocatalysts were integrated into a silica sol-gel synthesis in order to produce long-lasting coatings with self-cleaning and de-polluting properties on building materials. This simple synthesis allows the in situ application on buildings. The enhancement of TiO2 photoactivity by AuNPs was clearly demonstrated. The self-cleaning and de-polluting properties were evaluated using soot and NO, respectively, showing that AuNPs promote the TiO2 performance. In addition, the role of AuNPs size and their loading on TiO2 performance were investigated. It was demonstrated that the smallest AuNPs size (13 nm) and the intermedium gold content (0.5% w/w Au/TiO2) show the highest photoactivity.