Enhanced Photoelectrochemical Properties of Ti3+ Self-Doped Branched TiO2 Nanorod Arrays with Visible Light Absorption

A novel Ti3+ self-doped branched rutile TiO2 nanorod arrays (NRAs) was successfully grown on an F-doped tin oxide (FTO) transparent conductive glass by a combined hydrothermal and magnetron sputtering method. Surface morphology, structure, optical properties, and photoelectrochemical behavior of the branched TiO2 NRAs are determined. Using TiO2 nanoparticles (NPs) deposited on the top of the nanorods as seeds, TiO2 nanobranches can easily grow on the top of the nanorods. Moreover, the Ti3+ defects in the TiO2 NPs and associated oxygen vacancies, and the nanobranches expend the optical absorption edge of the TiO2 NRAs from 400 nm to 510 nm. Branched TiO2 NRAs exhibit excellent photoelectrochemical properties compared to the pure TiO2 NRAs, as revealed by photoelectrochemical measurements. This enhanced photoelectrochemical properties is induced by the increased surface area and expanded optical absorption range. Due to their favorable characteristics, these novel branched TiO2 NRAs will provide a new path to the fabrication of hierarchical nanostructured materials.