CARBONLETT, vol. 24, no. 1, pp.103-110, 2017
DOI: http://dx.doi.org/10.5714/CL.
Synthesis and physicochemical characterization of NixZnx- Fe2O4/MWCNT nanostructures as enzyme mimetics with peroxidase-like catalytic activity
Navvabeh Salarizadeh1, Minoo Sadri1,♠, Hassan Hosseini2 and Reza. H. Sajedi3
Affiliation: 1Department of Biochemistry and Biophysics, Education and Research Center of Science and Biotechnology, Malek Ashtar University of Technology, Tehran 16765-3454, Iran
2Department of Chemistry, Faculty of Sciences, Imam Hossein University, Tehran 16575-347, Iran
3Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 14115-175, Iran
Abstract: Carbon-based magnetic nanostructures in several instances have resulted in improved physicochemical and catalytic properties when compared to multi-wall carbon nanotubes (MWCNTs) and magnetic nanoparticles. In this study, magnetic MWCNTs with a structure of NixZnx- Fe2O4/MWCNT as peroxidase mimics were fabricated by the one-pot hydrothermal method. The structure, composition and morphology of the nanocomposites were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy and transmission electron microscopy. The magnetic properties were investigated with a vibrating sample magnetometer. The peroxidase-like catalytic activity of the nanocomposites was investigated by colorimetric and electrochemical tests with 3,3´,5,5´-tetramethylbenzidine (TMB) and H2O2 as the substrates. The results show that the synthesis of the nanocomposites was successfully performed. XRD analysis confirmed the crystalline structures of the NixZnx- Fe2O4/MWCNT nanohybrids and MWCNTs. The main peaks of the NixZnx- Fe2O4/MWCNTs crystals were presented. The Ni0.25Zn0.25Fe2O4/MWCNT and Ni0.5Zn0.5Fe2O4/MWCNT nanocatalysts showed nearly similar physicochemical properties, but the Ni0.5Zn0.5Fe2O4/MWCNT nanocatalyst was more appropriate than the Ni0.25Zn0.25Fe2O4/MWCNT nanocatalyst in terms of the magnetic properties and catalytic activity. The optimum peroxidase-like activity of the nanocatalysts was obtained at pH 3.0. The Ni0.5Zn0.5Fe2O4/MWCNT nanocatalyst exhibited a good peroxidase-like activity. These magnetic nanocatalysts can be suitable candidates for future enzyme-based applications such as the detection of glucose and H2O2.

Keyword: magnetic carbon nanotubes, peroxidase-like activity, characterization, biomimetic catalysts
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