Dependence of surface atomic arrangement of titanium dioxide on metallic nanowire nucleation by thermally assisted photoreduction

Through studying the optical, electrical and photocatalytic properties of anatase TiO₂ films with different preferred orientations, (101) and (004), this study clarified the relationship between the formation of metallic nanowires by thermally assisted photoreduction process and surface atomic bonding conditions of TiO₂. Experimental results show that the (101) anatase films which yielded much more Ag nanowires than the (004) oriented films and exhibited more complex superficial atomic bonding, which could be demonstrated by the Gaussian bands in photoluminescence spectra. This might lead to higher carrier concentration and mobility, as well as longer life time for photo-exited electrons and consequently a greater photocatalytic activity for reducing metallic ions. The fact that the anatase (101) surface acted as the preferred nucleation sites for Ag nanowires was supported by high resolution transmission electron microscopy lattice image of a TiO₂ nanofiber where an Ag nanowire was grown.