Visible light photocatalytic properties of Bi3.25Eu0.75Ti3O12 nanowires

Abstract

Europium doped bismuth titanate (Bi3.25Eu0.75Ti3O12, BEuT) 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), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The BEuT nanowires obtained were single-phase with an average diameter of 80nm, approximately. At room temperature, photoluminescence (PL) spectrum revealed that BEuT nanowires had two visible emission peaks at the wavelengths of 402nm and 554nm, which might arise from the excitonic emission and surface-defect, respectively. The UV-visible diffused reflectance spectrum (DRS) demonstrated that the band gap of BEuT nanowires was about 2.25eV. The as-prepared BEuT nanowires with good stability exhibited higher photocatalytic activities in the degradation of methyl orange (MO) under visible light irradiation (λ>420nm) than that in traditional N doped TiO2 (N-TiO2) and pure bismuth titanate (Bi4Ti3O12, BIT). The high photocatalytic performance of BEuT photocatalyst could be attributed to the strong visible light absorption and the recombination restraint of the e−/h+ pairs resulting from doping of Eu3+ ions.