Influence of silver doping on photocatalytic activity of liquid-flame-sprayed-nanostructured TiO ₂ coating

Silver ion was added to liquid feedstock to deposit Ag ⁺ -doped-nanostructured TiO ₂ photocatalytic coatings through liquid-flame spraying. The coating microstructure was characterized by x-ray diffraction (XRD). The photocatalytic performance of coatings was examined by photodegradation of acetaldehyde. The XRD analysis showed that the phase structure of coatings was not significantly influenced by the silver ion doping. However, a shift was found for XRD peaks of anatase TiO ₂. The photocatalytic activity of the TiO ₂ coatings increased and then decreased with the increase of dopant concentration. The photocatalytic activity of doped coatings was higher than that of pure TiO ₂ coating, regardless of the dopant concentration. The enhancement of photocatalytic performance of doped coatings is attributed to co-doping of Ag ⁺ ion and metallic Ag.