Low energy synthesis of nitrogen functionalized graphene/nanoclay hybrid via submerged liquid plasma approach

This study demonstrates that hard black (HB) (74% carbon, 26% clay; diameter: 0.5 mm) and 4 black (4B) (84% carbon, 16% clay; diameter: 0.5 mm) pencil carbon rods as electrode materials can produce highly dispersive nitrogen-doped few layer graphene/nanoclay hybrids (nanoclay-NFLG). The formation of nanoclay-NFLG was induced by applying high electrical potential across the pencil carbon rod and a platinum sheet electrode submerged in acetonitrile solvent. Electron microscopic analysis shows that in the HB- and 4B-nanoclay-NFLG, the nanoclay (size: >3 nm) was intercalated between the multilayer (>6 layers) of functionalized graphene. Raman spectra of HB- and 4B-nanoclay-NFLG shows a marginal increase in disorder compared to that of pure HB and 4B pencil carbon rods, respectively. X-ray photoelectron spectroscopy studies indicate the presence of pyridinic (NC) and pyrrolic (CHNH) nitrogen in both HB- and 4B-nanoclay-NFLG, which was also confirmed by ultraviolet-visible spectroscopy and infrared spectroscopy studies. The pyridinic and pyrrolic nitrogen present in HB- and 4B-nanoclay-NFLG gives distinct redox peaks in cyclic voltammogram, with high specific capacitances of 40 and 111 F/g, respectively, obtained at the scan rate of 5 mV/s.