Photocatalytic Activity of Ag/TiO2 Nanotube Arrays Enhanced by Surface Plasmon Resonance and Application in Hydrogen Evolution by Water Splitting

TiO2 nanotube arrays (TiO2 NTs) were fabricated by anodic oxidation and then Ag nanoparticles (Ag NPs) were assembled in TiO2 NTs (Ag/TiO2 NTs) by microwave-assisted chemical reduction. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence spectrum (PL), UV-vis absorption spectrum (UV-vis), and Raman spectrum, respectively. The results showed that Ag NPs were well dispersed on the surface of TiO2 NTs with metallic state. The surface plasmon resonance (SPR) effect of Ag NPs could extend the visible light response and enhance the absorption capacity of TiO2. Furthermore, Ag NPs could also restrain the recombination of photo-generated electron-hole pairs of TiO2 NTs efficiently. The methylene blue photodegradation experiment proved that the SPR phenomenon had an effect on photoreaction enhancement. The results of photocatalytic water splitting indicated that Ag/TiO2 NTs samples had better photocatalytic performance than pure TiO2 NTs. The corresponding hydrogen evolution rate of Ag/TiO2 NTs prepared with 0.002 M AgNO3 solution was 3.3 times as that of pure TiO2 NTs in the test condition. Additionally, the mechanism of catalyst activity enhanced by SPR effect was proposed.