Effects of NH4F quantity on N-doping level, photodegradation and photocatalytic H2 production activities of N-doped TiO2 nanotube array films

Abstract

Series of N-doped TiO2 nanotube array (NTA) films with various N-doping levels and tube lengths were prepared by a facile one-step anodization method, simply changing NH4F quantity in electrolyte. The crystal structures, morphologies and compositions of the samples were analyzed by XRD, SEM, TEM and X-ray photoelectron spectra (XPS). The optical properties were investigated by means of UV–vis absorption spectra and photoluminescence (PL) spectra. Their photocatalytic activities were assessed by photodegradation of rhodamine B (RhB) solution and photocatalytic water splitting to generate hydrogen, respectively. The photocatalytic reaction mechanism was investigated and discussed. The results show that NH4F quantity greatly influences the N-doping level and tube length of the TiO2 NTA, which subsequently affects the optical properties and photocatalytic activities. The photodegradation and photocatalytic H2 production activities of the N-doped TiO2 NTAs can be simply regulated by tuning NH4F quantity in electrolyte during preparation.