Highly ordered Ag–TiO2 nanocomposited arrays with high visible-light photocatalytic activity

TiO2 is active only in the ultraviolet region. To enhance the active ability, a combined method consisting of the anodic oxidation method and the hydrothermal method was developed to prepare highly ordered Ag-TiO2 nanocomposited arrays. The anodic oxidation was used to synthesize amorphous nanotubes with high chemical activity that subsequently served as highly ordered templates in preparing the final sample. The amorphous nanotubes got converted to highly ordered Ag-TiO2 (anatase) arrays in the silver nitrate & glucose aqueous solution via hydrothermal treatment. SEM and TEM results show that the Ag-TiO2 nanocomposite was composed of a large number of Ag nanoparticles and anatase TiO2 nanoparticles, and the morphology of those at the top of the arrays was found different from that of its trunk. The morphology evolution mechanism of the obtained sample was discussed. It is also revealed that the Ag-TiO2 nanocomposite has high visible-light photocatalytic activity.