Synthesis and characterization of CuO–montmorillonite nanocomposite by thermal decomposition method and antibacterial activity of nanocomposite

• We used thermal decomposition method for synthesis of CuO/MMT nanocomposite.
• The antibacterial activity of CuO–MMT nanocomposite was tested against Escherichia coli.
• The minimum inhibitory concentration value against E. coli of CuO–MMT was 0.1 ng/mL.
• The XRD result implied that CuO nanoparticles can exist in micropore of MMT.
• The FT-IR spectra confirm substitution of aluminum in octahedral layer by Cu2+ cations.

CuO–montmorillonite (CuO–MMT) nanocomposite was synthesized by thermal decomposition methods and characterized by diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The resultant particles are nearly spherical and particle size is in the range of ∼3–5 nm. X-ray diffraction patterns indicate that MMT (1.22 nm) has a d-spacing higher than CuO–MMT nanocomposite (0.97 nm). This result implied that CuO nanoparticles can exist in micropore of MMT. The disappeared of band at 918 cm−1 and decreasing of intensity of 3630 cm−1 band in FT-IR spectra confirm substitution of aluminum in octahedral layer by Cu2+ cations. The diffuse reflectance spectra show that the value of band gap energy for CuO–MMT nanocomposite (2.7 eV) is more than CuO nanoparticles (1.2 eV). It was found that decrease in the particle size of CuO nanoparticles due to quantum size effect. The antibacterial activity of CuO–MMT nanocomposite was tested against Escherichia coli. Nanocomposite showed efficient bactericidal effect.

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