The novel behavior of photoelectrochemical property of annealing TiO2 nanorod arrays

Photoelectrochemical (PEC) properties of as-prepared TiO2 nanorod arrays (NRAs) are shown to be positively related to the annealing temperature in the studies. We report the experimental evidences on the saturation behavior of PEC properties responding to the annealing temperature of the TiO2 NRAs. The effect of the annealing temperature ranging in 250–550 °C on the surface morphology, crystalline size, crystal structure, surface chemical states, band-gap, optical and photoelectrochemical performance has been scrutinized. It is found that the photocurrent density of the annealing TiO2 NRAs at 450 °C under air atmosphere for 1 h is the highest and about six times higher than that of the as-prepared samples. However, the PEC performance has been deteriorated with further increase in temperature. The underlying mechanism could be understood by the morphology and crystal size variations of the TiO2 NRAs annealed. It is evidently shown that the PEC performances exhibit strong optimization behavior in response to the annealing temperature, which is an effective method for further improving PEC property for water splitting and other electrical device performance of the TiO2-based materials.