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

Abstract

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.