TiO2, photocatalyst, Ag, doping, photodegradation
In this work, TBOT was used as the titanium source for preparation of TiO2 nanoparticles, followed by calcination at 500°C for 2 hours to achieve fine TiO2 nanoparticles powder (S1). The obtained S1 powder was then used to fabricate two different TiO2 photocatalysts containing Ag. Firstly, The S1 powder was dispersed in the AgNO3 solution to form a suspension, followed by calcination at 450°C for 1 hour to form Ag/TiO2 composite nanoparticles (S2). Afterwards, the Ag nanoparticles on the surface of S2 composite were removed via a dissolution reaction of Ag in nitric acid to obtain Ag-doped TiO2 nanoparticles (S3). The UV and visible light photocatalytic activities of the three samples were evaluated and compared by photodegradation of methyl orange (MO) solutions under the irradiation of a 350W Xenon lamp. The concentrations of MO solutions were determined by UV-vis absorption spectra. The photodegradation rate of MO solution for S3 is the fastest, and the order of photocatalytic ability is S3> S2> S1. It was then deduced that the TiO2 photocatalyst containing Ag shows different photocatalytic mechanisms under UV and visible light.