Synthesis and characterization of zinc-aluminum based layered double hydroxide and oxide nanomaterials by performing different experimental parameters

Abstract

Zinc-aluminum based layered double hydroxide (ZnAl-LDH), -oxide (ZnO), -mixed oxide (Zn₆Al₂O₉), and zinc-aluminum mixed oxide/polyvinyl alcohol (ZnAl-mixed oxide/PVA) nanocomposite have been synthesized. The samples were characterized using some analytical methods: Ultraviolet-visible spectroscopy, Fourier transforms infrared (FTIR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The XRD patterns of ZnAl-LDH_5M and ZnAl-LDH_2M show the characteristic reflections of ZnO phase beside the hydrotalcite-like structure. Using NaHCO₃ in the experiment, the precipitation speed of the sample was high and in this regard, the particle size of ZnAl-LDH_urea(1) was 22.37 nm. ZnAl-LDH_2M and ZnAl-LDH_5M describe three optical band gaps with three different energies. For ZnAl-mixed oxide/PVA, there are two types of electronic transitions could exist at ZnO which attributed to the filled O2p orbital and that associated to the empty Zn 4s orbital, with the possibility of some Zn 4p orbital. Another electronic transition could exist for Zn₆Al₂O₉ between the filled O 2p orbital and the empty Al 3s orbitals, with the additional possibility of some Al 3p orbital. The intense FTIR band at very low wavenumber is observed for only ZnAl-LDH_urea(2) which attributed to the Zn-O-bound for brucite-like LDH structures.

Graphical Abstract

Keywords:

• Layered double hydroxides (LDHs)
• mixed oxide
• polymer nanocomposite
• coprecipitation method
• structural properties

Acknowledgment

Author thanks the High Molecular Compounds Chemistry sub-department (BSU) for laboratory facilities and Nano-Research Center laboratory for physicochemical characterization of nanomaterials.

Additional information

Funding

This work was supported by the “Baku State University 50 + 50/2018-2019” Project.