Nitrogen Doped 3D Titanium Dioxide Nanorods Architecture with Significantly Enhanced Visible Light Photoactivity

Surface-reaction-limited pulsed chemical vapor deposition (SPCVD) is able to create 3D TiO2-based hierarchical nanowire (NW) architecture with superhigh surface area and good electronic transport properties for high-performance photoelectrode development. However, how to intentionally dope the nanorods (NRs) through the SPCVD process to improve their electronic properties and light absorption behavior is still unexplored. In this paper, a comprehensive study of doping TiO2 NRs with nitrogen through the SPCVD technique is reported for the first time. The high-density nitrogen doped TiO2 NR branches with controlled doping concentrations were synthesized on dense Si NW forest by introducing designed number of TiN cycles to TiO2 growth cycles. Microscopic studies revealed the influence of nitrogen doping on the crystal growth behavior and NR morphology, as well as the elements distribution inside the lattices. Nitrogen doping lowered the band gap of TiO2 NRs and effectively activated visible light photoactivi...