Chemical modification of carboxylated MWCNTs for enhanced electrical conducting and magnetic properties

An electrical conducting and magnetic nanomaterial, [Ni(II)Hyd]-MWCNTs was synthesized via chemical modification of carboxylated MWCNTs (A-MWCNTs). The synthesized material has been studied by FTIR, UV-Visible, XPS, Raman, TGA, powder XRD, TEM and EDAX analysis. Double probe DC conductivity suggested enhanced electrical conductivity of [Ni(II)Hyd]-MWCNTs compared to A-MWCNTs. (R(s)Q(RctO)) is found to be best fit Randle's equivalent circuit. The positive slope obtained from Mott-Schottky plot suggested n-type semiconducting behavior of materials. The positive shift in flat-band potential for [Ni(II)Hyd]-MWCNTs is the signature of its more conducting nature than that of A-MWCNTs. The better conductivity of [Ni(II)Hyd]MWCNTs is also confirmed by optical and electrochemical band gap studies. The field and temperature dependent magnetization revealed intrinsic ferromagnetism in [Ni(II)Hyd]-MWCNTs with enhanced saturation magnetization, remanent magnetization and coercivity values compared to A-MWCNTs. Hence, high electrical conductivity and magnetic properties prompt the [Ni(II)Hyd]-MWCNTs for applicability in spin-based electronic devices and in other application such as EMI shielding, metamaterials, drug delivery, anticorrosion, etc.