Supercritical processing of thermally stable multiwalled carbon nanotube/boron nitride nanohybrids with synergistically improved electrical conductivity

Abstract

A novel method of processing of thermally stable nanohybrids (NHs) with synergistically improved electrical conductivity (σDC) has been developed in supercritical carbon dioxide (SCC). Processing of NHs was executed through dispersion of selected weight fractions (wt%) of hexagonal boron nitride (h-BN) into carboxylate functional multiwalled carbon nanotube (c-MWCNT) at 1200 psi, 90 ± 1°C over 5 hr in SCC. Formation of NHs was ascertained through diverse analytical methods. Scanning electron microscopy coupled with energy dispersive spectra, elemental mapping and X-ray diffraction analysis reveals deposition of h-BN over the surface of c-MWCNT. NHs derived at 5 wt% of h-BN has shown reduced optical band gap (Eg, 3.34 eV) with 41 % increase in crystallite size. Working electrodes (WEs) derived from NHs has rendered increasing trend of DC conductivity (mS/cm) with concentration of h-BN up to 5 wt% at 100 V. WEs involving h-BN (5 wt%) has shown enhanced DC conductivity (0.93) followed by c-MWCNT (0.63) and h-BN (0.41) at 100 V. Present investigation delivers a clean, dry and environmentally benign method of processing of NHs suitable for development of inexpensive WEs for potential applications in hydrogen storage, electrocatalysis and sensors.