Formation of vertically grown 1D TiO₂ nanorods on the surface of Al₂O₃/Ti composites by simple heat treatment and their photocatalytic performance

Abstract

A simple method was used to form one-dimensional (1D) TiO₂ nanorod arrays on the surfaces of hot-pressed Ti-dispersed Al₂O₃ composites by heating. After heating below 600°C, the Ti surface morphologies had changed significantly, while the Al₂O₃ surfaces remained unchanged. After heating for 5 h above 500°C, vertically grown nanorods were observed on the surfaces of Ti grains among Al₂O₃/Ti composites, which exhibited a crystalline phase of rutile-type TiO₂ doped with a small quantity of aluminum. Nanorod formation was believed to be due to Ti diffusion and its acceleration by Al incorporation. The photocatalytic activity of the heated Al₂O₃/Ti composites was verified by rhodamine B degradation under ultraviolet light irradiation, although the oxide fraction on the composites was small. The activity was enhanced by 1D TiO₂ nanorod growth on the composite surface.