On Structure, Optical Properties and Photodegradated Ability of Aurivillius-Type Bi₃TiNbO₉ Nanoparticles

Bi₃TiNbO₉ nanoparticles with an acceptor dopant of Ni²⁺ ion were prepared by the conventional Pechini sol–gel synthesis. The X-ray polycrystalline diffraction measurements (XRD) and the Rietveld refinements of Bi₃TiNbO₉ samples were completed. The surface property of Bi₃TiNbO₉ nanoparticles was investigated by transmission electron microscope, scanning electron microscope), and N₂ adsorption–desorption isotherms. Bi₃TiNbO₉ nanoparticles showed an optical band gap with energy of 3.1 eV in the UV region. While the Ni²⁺-doping could greatly reduce the band energy of Bi₃TiNbO₉:xNi²⁺ nanoparticles to 2.79 eV (x = 0.05) and 2.61 eV (x = 0.1). This indicates that the Ni-doped samples could be excited by UV–visible light. The photocatalytic abilities were tested by the photodegradation on methylene blue solution (MB) and phenol solutions excited by visible light. Accordingly, the photocatalytic activity was improved by the Ni-doping in B-sites in this Aurivillius-type structure. The results concluded that Bi₃TiNbO₉:Ni²⁺ would be a possible candidate as a visible light-driven photocatalyst. The effective photocatalysis was discussed on the structure characteristic and experiment such as polarized Aurivillius (Bi₂O₂)²⁺ layers, luminescence, and decay lifetimes, etc. © 2016 The American Ceramic Society