Enhancing the light absorption and dielectric properties of nitrate intercalated Zn-Al Layered double hydroxide through anionic exchange with ethylenediaminetetraacetate

Herein, we have reported a comparative study of two Zn-Al Layered double hydroxides (LDH) intercalated by nitrate (NO ₃ ⁻ ) and ethylenediaminetetraacetate (EDTA) ions, respectively. Indeed, nitrate-intercalated LDH was prepared by the coprecipitation method at a constant pH with Zn/Al = 2 (molar ratio), and used as a precursor for the synthesis of EDTA intercalated LDH through the anionic exchange method. Subsequently, these two LDH were analyzed by inductively coupled plasma, characterized by X–ray diffraction, thermogravimetric analysis and three spectroscopic techniques: Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy and impedance spectroscopy. The exchange of nitrate ions by EDTA led to a decrease in the electrical conductivity, dielectric constant and dielectric loss tangent, and revealed an important increase in the absorption coefficient in UV–Vis–NIR range, with a large gap energy of approximately 6.30 eV. This work demonstrates the advantage of EDTA ions in decreasing the dielectric dissipation energy, and improving the light absorption of LDH compound.