Preparation and photoelectric properties of Pt/TiO2 nanotube electrodes by a pre-doping method

Highlights: • Platinum (Pt) nanoparticles were doped before the formation of Titanium Dioxide Nanotubes (TNT). • The pre-doping method can avoid pore blocking. • Pt nanoparticles at the bottom diffused into the upper TNT film after annealing. • The pre-doping method can successfully realize Pt nanoparticles decorating TNT. • The photoelectric properties of Pt/TNT are superior to pure TNT. - Abstract: A pre-doping method in which Pt nanoparticles (NPs) are introduced as dopants before the formation of a TiO₂ nanotube (TNT) array was proposed in this paper. This method was intended to decorate a TNT array film with Pt nanoparticles (Pt/TNT), which effectively avoided the problem of blocking the top of the nanotubes by noble metal particles by post-doping methods. Pt/TNT array film was fabricated by anodizing the double Pt/Ti metal film, which was obtained by successive magnetron sputtering of Pt and Ti films onto FTO substrates. X-ray diffraction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy were used to characterize the microstructure of the Pt/TNT nanotubes array, which revealed that Pt NPs located at the bottom of the Ti film can diffuse into the upper TNT array film after anodization and annealing. Pt/TNT electrode exhibits a superior photoelectric property over that of TNT, of which the photocurrent value of the Pt/TNT electrode was more than twice that of the pure TNT electrode. It is therefore obvious that the pre-doping method is feasible and effective for fabricating a high-photocatalytic-efficient Pt/TNT electrode.