Visible light photocatalytic properties of Bi 3.25La 0.75Ti 3O 12 nanowires

Abstract

Lanthanum-doped bismuth titanate (Bi 3.25La 0.75Ti 3O 12, BLT) nanowires were synthesized by a one-step hydrothermal process and their optical and photocatalytic properties were investigated. Their crystal structure and microstructures were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The BLT nanowires obtained are single-phase with an average diameter of 25 nm. The room temperature photoluminescence (PL) spectrum reveals two visible emission peaks at 400 and 596 nm, which are assigned to excitonic and surface-defect emissions, respectively. The UV-visible diffuse reflectance spectrum (UV-Vis DRS) reveals that the band gap of BLT nanowires is 2.07 eV. The prepared BLT nanowires are stable and exhibit higher photocatalytic activities in the degradation of methyl orange (MO) under visible light irradiation (λ >420 nm) compared with commercial P25 TiO2, traditional N-doped TiO2 (N-TiO2), and pure bismuth titanate (Bi 4Ti 3O 12, BIT). The high photocatalytic performance of BLT photocatalysts is attributed to the strong visible light absorption and the recombination restraint of the e -/h + pairs resulting from the presence of La 3+ ions. © Editorial office of Acta Physico-Chimica Sinica.