Enhanced photochemical response of TiO2/CdSe heterostructured nanowires

High-density single-crystalline TiO2 nanowires (similar to 50 nm diam) were successfully grown on Ti substrates by chemical vapor deposition at a low temperature of 700 degrees C and within a remarkably short time period of 5 min. They were combined with CdSe nanocrystals (similar to 5 nm diam) to form TiO2/CdSe heterotructured nanowires by overcoating the nanowires with the CdSe-containing solution and subsequent annealing at 600 degrees C. The TiO2/CdSe nanowires showed uniformly distributed CdSe nanocrystals, and high crystallinity of rutile and wurtzite from the TiO2 and the CdSe, respectively. Owing to the heterostructure of the TiO2/CdSe, they demonstrate almost full visible-range light absorption and thus enhanced photocatalytic activity by charge separation via electron and hole transfer between the CdSe and the TiO2.