Silver ion was added to liquid feedstock to deposit Ag+ doping 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. 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 was increased and then decreased with the increase of dopant concentration. The photocatalytic activity of doping coatings was higher than that of pure TiO 2 coating, in spite of dopant concentration. The enhancement of photocatalytic performance of doping coatings is attributed to co-doping of Ag+ ion and metallic Ag.

Copper ion was added in liquid feedstock to deposit ion doping TiO 2 photocatalytic coatings through liquid flame spraying. The coating microstructure was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of coatings was examined by photodegradation of acetaldehyde. XRD analysis shows that the crystalline structure of coatings is not significantly influenced by the metal ion doping. The photocatalytic activity of the TiO 2 coatings is enhanced by the copper ion doping. It is found that a high concentration of ion doping decreases the activity. XPS analysis shows that the adsorbed oxygen concentration is increased with the increase of Cu 2+ dopant concentration and decreases with the further increase of dopant concentration. The enhancement of photocatalytic activity can be attributed to the adsorption ability of oxygen and other reactants on the surface of doping TiO 2 coatings.