Synthesis of Superparamagnetic Cu_0.4Zn_0.6Fe₂O₄-Implanted Bi₂S₃-Capped TiO₂ 2D and 3D Nanostructures for Visible Light...

Sharp narrow nanopetal-like and wrinkled nanoball-like cubic Cu_0.4Zn_0.6Fe₂O₄-implanted orthorhombic Bi₂S₃-capped anatase TiO₂ heterostructures have been synthesized by a two-step hydrothermal process in acidic and basic environments. They have been characterized by high-resolution scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, selected area electron and powder X-ray diffractometries, vibrating sample magnetometry, UV-visible diffuse reflectance and photoluminescence spectroscopies, and nitrogen adsorption-desorption analysis. Both the nanostructured composites are superparamagnetic. While the nanocomposite synthesized in acidic environment absorbs in the entire visible and UV spectral regions, the absorption edge of nanocomposite obtained in basic environment narrowly misses the red end of the visible spectrum. The emission spectra of both the nanomaterials are strikingly similar, indicating similar crystal defects in anatase TiO₂ lattice of both the nanocomposites. Although both the nanocomposites degrade dye under visible light, the photocatalytic activity of the sample obtained in acidic environment is superior to that prepared in basic condition. The enhanced photocatalytic activity of the nanocomposite synthesized in acidic environment is rationalized in terms of nanostructure, surface area, and optical properties.