Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

Biomass has become of recent interest as a raw material for ‘green’ graphenic carbon (GC) since it promotes an environmentally friendly approach. Here, we investigate a single pyrolysis route to synthesize GC from coconut shells which provides a simple method and can produce a high yield, thus being convenient for large-scale production. The pyrolysis involves a stepped holding process at 350°C for 1 h and at 650°C or 900°C for 3 h. The GC sample resulted at the 900°C pyrolysis has a thinner sheet, a less porous structure, a higher C/O ratio, and an enhanced electrical conductivity than those pyrolyzed at 650°C. The addition of Na3PO4 catalyst has no significant effects on the GC structures obtained by this route. The single pyrolysis route generates thinner GC sheets compared to the two-step heat treatment followed by the liquid phase exfoliation (LPE) procedure. Nevertheless, the latter method offers a formation of clean samples with a porous or holey feature which has potential for advanced energy-storage applications.