Vertically Aligned Core-Shell PbTiO₃@TiO₂ Heterojunction Nanotube Array for Photoelectrochemical and Photocatalytic Applications

Vertically aligned core-shell PbTiO₃@TiO₂ heterojunction nanotube arrays are fabricated on F:SnO₂ (FTO) glass substrate via a unique three-step process: an electron beam vapor deposition of Ti thin film on FTO, anodic oxidation of the Ti film to TiO₂ nanotubes, and finally formation of PbTiO₃ perovskite layer at the inner wall of the TiO₂ nanotubes. The PbTiO₃@TiO₂ nanotube array exhibits dramatically improved photoactivity relative to TiO₂ nanotubes or PbTiO₃/TiO₂ composite powders in photoelectrochemical water splitting and photocatalytic isopropyl alcohol decomposition under visible light irradiation (>420 nm). In the core-shell heterojunction electrodes, PbTiO₃ serves as a visible light responsive inorganic photosensitizer with its small band gap and forms a heterojunction with TiO₂ for effective charge separation. (Chemical Equation Presented).