Defect and Magnetic Properties of Reduced Graphene Oxide Prepared from Old Coconut Shell

Defect state may be created on the grafitic bonding of carbon atoms as the dangling bonds of the reduced graphene oxide (rGO) compound. In this study, the rGO sample has been prepared by burning the coconut shell in air. The resulted burnt samples were then heated at varying temperatures (400, 700, and 1000°C) for 5 hours in air. Further, a mechanical exfoliation process using ultrasonic vibrator was added to the samples for 5 hours. Characterization using Raman spectroscopy exhibited that the intensity ratio of defect (I_D) and graphene (I_G) increases, implying the increase of defect number, with respect to the increasing heating temperature. According to the magnetic property measurement using vibrating sample magnetometer (VSM), it is shown that the magnetization enhances with incerasing number of defects, featuring an occurrence of defect-induced magnetism in rGO.