The effect of Ag nanoparticle loading on the photocatalytic activity of TiO2 nanorod arrays

Ag nanoparticles with different loadings were systematically coated onto uniformly aligned TiO2 nanorod arrays. The enhanced photocatalytic decay rates were found to increase linearly with the Ag nanoparticle load until a maximum photodecay rate was reached at 0.25 wt.% Ag loading, and then decrease almost linearly with further increasing Ag loading. A simple reaction model based on the Ag nanoparticle coverage and charge trapping is proposed, and the predicted results agree very well with the experimental results quantitatively. The effective lifetime of photogenerated holes due to the trapping of the Ag nanoparticles on the surface of TiO2 nanorods was estimated to be approximately three times that of pure TiO2 nanorods.