Abstract In this paper, nickel oxide (NiO) nanoparticles have been fabricated using wet method and deposited on the surface of multi-walled carbon nanotube (MWCNT). To do so, functional groups were introduced on the surface of MWCNTs by treating with concentrated nitric acid. Nickel oxide nanoparticles were formed on the surface of functionalized MWCNTs by incipient wetness impregna- tion of nickel nitrate, and the resultant product was calci- nated in air atmosphere. Characteristics of the NiO/ MWCNT were examined by various techniques, for example, Fourier transform spectroscopy (FTIR), X-ray diffraction analysis (XRD), transmission electron micro- scopy (TEM), thermogravimetric analyzer (TGA), and nitrogen adsorption–desorption isothermal as well as vibrating sample magnetometer (VSM). The FTIR spectra showed that carboxyl and hydroxyl functional groups existed on the surface of MWNTs after modification by concentrated nitric acid. The pattern of XRD indicated that MWNTs and nickel oxide nanoparticles coexisted in the NiO/MWCNT sample. The TEM images revealed that the NiO nanoparticles were distributed on the surface of the MWNTs, with the size ranging from 5 to 60 nm. Ther- mogravimetric analysis proved that NiO content decorated on MWCNTs was 80 and 15 wt%. The results of the Brunauer–Emmett–Teller (BET) data showed that the slight increment in the specific surface areas and porosities in the presence of the NiO nanoparticles on the surface of CNT

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