Exploration of silver decoration concentration to enhance photocatalytic efficiency of titanium dioxide photocatalysts

Ag decoration on TiO2 is favorable to absorption of visible light and wider absorption range. Ag nanoparticles playing the role of electron receivers on TiO2 surface enhance photodegradation. However, excess Ag nanoparticles caused reduced specific surface area of photocatalysts and increased probability of charge recombination, resulting in lower photocatalytic efficiency. In this study, the influence of various Ag decoration concentrations on photocatalytic activity was investigated. Surface treatment by nitric acid after Ag decoration was performed to avoid excessive Ag deposition. The extent of Ag elimination and its impacts on photocatalytic activity were also explored. An optimum Ag content in the photocatalyst was achieved and photocatalytic efficiency was obviously improved. It was found that the number of calcination times affected the crystallinity and stability of photocatalysts. Better photocatalytic efficiency could be obtained after twice calcinations. [Display omitted] •The impact of Ag decoration concentration on photocatalytic activity of TiO2 photocatalysts has been investigated.•The most appropriate AgNO3 concentration for Ag decoration was 0.02 M.•Surface treatment by appropriate HNO3 concentration after Ag decoration was performed to achieve the optimum Ag content.•Photocatalytic efficiency was impacted by Ag decoration on the surface and probably not affected by Ag doping inside.•Higher photocatalytic efficiency was obtained by twice calcinations due to higher crystallinity and more stable structure.