Single-crystalline Bi5O7NO3 nanofibers: Hydrothermal synthesis, characterization, growth mechanism, and photocatalytic properties

Abstract

A new photocatalyst, namely single-crystalline Bi(5)O(7)NO(3) nanofibers, was prepared by a facile hydrothermal method in the presence of Triton X-100 and ammonia. Bi(5)O(7)NO(3) possessing a crystalline sheet morphology could be dissolved and transformed into nanofibers by controlling the reaction time. Samples were characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. The Bi(5)O(7)NO(3) nanofiber growth mechanism is discussed in detail. The band gap energy of the as-prepared Bi(5)O(7)NO(3) photocatalyst was about 2.70-2.90eV. Results of first-principle density functional theory calculations confirmed that Bi(5)O(7)NO(3) had a narrow band gap. They revealed that the conduction band bottom was predominantly composed of Bi 6s, Bi 6p, N 2p and O 2p orbitals, while the valence band (VB) top primarily consisted of Bi 6p, Bi 6s and O 2p orbitals. The as-obtained Bi(5)O(7)NO(3) nanofibers showed good photocatalytic activity and stability for the degradation of Rhodamine B (RhB) under visible light irradiation, which may be ascribed to the highly mobile conduction band (CB) and VB charge carriers.