Topotactic synthesis and photocatalytic performance of one-dimensional ZnNb2O6 nanostructures and one-dimensional ZnNb2O6/KNbO3 hetero-nanostructures

Abstract

This paper introduces one-dimensional ZnNb₂O₆/KNbO₃ hetero-nanostructures and one-dimensional ZnNb₂O₆ nanostructures. These nanostructures are synthesized via in situ topotactic structural transformation reaction using the tunnel structure K₂Nb₂O₆ filiform crystal as precursor. Firstly, Zn²⁺ ions intercalate into K₂Nb₂O₆ crystal by exchanging K⁺ ions from the K₂Nb₂O₆ crystal with Zn²⁺ from Zn(NO₃)₂ or Zn(CH₃COO)₂ aqueous solution, to form two different Zn²⁺-exchanged samples, and then these Zn²⁺-exchanged samples topotacticly transform into one-dimensional ZnNb₂O₆/KNbO₃ hetero-nanostructures and ZnNb₂O₆ nanostructures during heat-treatment. The formation reaction and structure of these samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and energy-dispersive spectroscopy (EDS). Photocatalytic experiments showed that one-dimensional ZnNb₂O₆/KNbO₃ hetero-nanostructures and ZnNb₂O₆ nanostructures have excellent photocatalytic performance for the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO).