Physical Properties Comparison of rGO-like phase prepared from Coconut Shell and the Commercial Product Retno Asih, Maya Mahirotul Septya, Erik Bhekti Yutomo, Fahmi Astuti, Malik Anjelh Baqiya, Darminto Darminto

Abstract

Physical properties of reduced graphene oxide (rGO) prepared from two different raw materials, namely coconut shell (rGO-s) and graphite mineral (rGO-c, produced by Graphenea Inc.), have been investigated. While both samples have the same density of about 1.9 g/cm³, rGO-c has more porous of about 1.3 cc/g with diameter of 10.8 nm compared to rGO-s which has 0.2 cc/g porous with diameter of 2.4 nm. Specific surface area in rGO-c was also obtained much larger than that of rGO-s. rGO-c and rGO-s have specific surface area of ~298 m²/g and ~475 m²/g, respectively. Examinations on particle size and surface morphology show that rGO-c has homogenous particles which consist of transparent thin sheets, while rGO-s has rather heterogenous particles that look like dens stacked sheets. The presence of C and O was confirmed at the observed morphology. The difference in physical features were then found to influence the obtained electrical conductivity of the samples. rGO-c has higher conductivity than rGO-s. Estimation on gap energy (E_g) indicates that rGO-c and rGO-s have E_g in the range of semiconducting materials. The study provides a better understanding on physical properties of coconut shell-derived rGO to further revise synthesis method to improve quality of the obtained rGO.