Tuning the visible-light-driven photocatalytic properties of multi-decorated TiO2 by noble metals towards both propionic acid and NOx degradation

Multiple noble metals-modified micrometric TiO2-based photocatalysts were prepared by a cheap and sustainable approach based on the use of metal-enriched wastewaters (Ag, Au, Pt) and used for the photodegradation of propionic acid (PA) and NOx under LED. Properly tuning the metal decoration step, the material's photoactivity was optimized. 0.1%Pt @Ag/TiO2 led to 60% PA removal, whereas the strong PA adsorption on the 0.1%Au @Ag/TiO2 surface caused a partial deactivation. In contrast, 0.1%Au @Ag/TiO2 showed the highest photoactivity in the NOx decomposition (90%) due to the high tolerance of Au to HNO3 produced on the catalyst surface.