Dimensional control of titanium dioxide nanotube arrays with hydrogen peroxide content for high photoelectrochemical water splitting performance

Adding hydrogen peroxide (H₂O₂) for the fast formation of titanium dioxide (TiO₂) nanotube arrays produce smooth and clean TiO₂ nanotubes without bundling and cracking problems. The nanotube formation rate accelerated after the periodical addition of H₂O₂ at different intervals. Adding H₂O₂ at 10 min intervals formed longer nanotubes (13 m) with larger pore diameters (140 nm). These novel TiO₂ nanotubes exhibited optimal photocurrent density (1.8 mA/cm²) and 3.8% photoconversion efficiency because of high crystallinity with numerous oxygen vacancies in the large pore diameters allowed for better light absorption and good interaction between the electrolytes and TiO₂ nanotubes.