Dual modification of TiO2 nanorod arrays with SiW11Co and Ag nanoparticles for enhanced photocatalytic activity under simulated sunlight.

Well-organized TiO2 nanorod arrays (TNRs) have increasingly attracted our attention in recent years due to their excellent photocatalytic properties. However, it is of great importance to prepare more efficient photocatalysts using a facile method towards their more widespread use. In this work, K6SiW11O39Co(ii)(H2O) (SiW11Co) and Ag nanoparticles were introduced into TNRs using spin-coating and chemical bath deposition methods. It was found that TNRs/SiW11Co/Ag composite films with an active area of only 1 cm2 exhibit highly efficient and sustainable properties for the photodegradation of NO2 and display a significant enhancement compared with P25 and pure TNRs. Photocatalytic measurements demonstrated that both SiW11Co and Ag synergistically improve the light absorption and charge separation efficiency, thus obtaining the most efficient photocatalytic performance. In addition, the probable photocatalytic mechanism and the dominating active species for NO2 photodegradation were also proposed, in order to testify the effectively enhanced photocatalytic ability of the TNRs/SiW11Co/Ag composite. Hence, the design of these polyoxometalate and metal particle co-modified TNRs may provide a new tactic for developing promising materials for photocatalytic degradation.