Abstract: A highly ordered TiO₂/Au nanorod array was successfully fabricated by direct current electrodeposition and subsequent spin-coating. Scanning electron microscopy and transmission electron microscopy images revealed that the TiO₂ film completely covered the surface of the Au nanorods, which resulted in TiO₂ shell Au core nanorods. X-ray diffraction patterns revealed that the TiO₂ film was anatase with preferential orientation in the (101) plane. UV-Vis diffuse reflectance spectra showed a shift in the absorption edge toward the visible region because of the formation of a Schottky junction between Au and TiO₂. A new absorption peak that ranged from 400 to 800 nm appeared because of the localized surface plasmon resonance of the Au nanorod arrays. For the photocatalytic degradation of rhodamine B under UV light irradiation, the TiO₂/Au nanorod array exhibited excellent photocatalytic activity and its kinetic constant was 2.0 times that of pristine TiO₂ and 1.3 times that of a TiO₂/Au film. The enhanced photocatalysis was attributed to the high surface volume ratio, an improved UV light response, efficient separation, and the convenient migration of photogenerated charge carriers because of the one-dimensional nanorod structure and the Schottky junction between Au and TiO₂. This work could provide new insights into the fabrication of a high performance photocatalyst and thus facilitate practical environmental applications.

Key words: titania, gold nanorod array, Schottky junction, photogenerated charge carrier separation, photogenerated charge carrier migration, photocatalytic activity