Enhanced Magnetism by Temperature Induced Defects in Reduced Graphene Oxide Prepared from Coconut Shells

Magnetism of graphene-based compounds has drawn growing interest owing to its tunability by various defects presented in the compounds. Reduced graphene oxides (rGOs), particularly, provide an ideal playground as they have significant defects and functional groups on their layers. Herein, we propose a green synthesize method, a simple way in preparing rGO from coconut shells. The rGO has been synthesized from coconut shells by thermal reduction process at 400 °C, 600 °C, and 1000 °C followed by an exfoliation process. We found that the rGO sample prepared at 1000 °C (rGO-1000) exhibits stronger room temperature magnetization, where the saturation magnetization increases approximately 35 times as large as those prepared at 400 °C (rGO-400) and 600 °C (rGO-600). The concentration of defects increases and the oxygen-containing functional groups reduce with an increase in the heating temperatures, contributing to the increment in magnetization. The observed results in this paper indicate that defect-induced magnetism of the obtained rGO can be enhanced by controlling the temperature in the reduction process.