Fabrication and optimization of activated carbon-based graphene oxide from rice husks as an alternative to graphite

Abstract

Processing of renewable, abundant, and low-cost biomass into graphene materials such as porous carbon materials for application in the environmental field, electronics and clean energy has been attracting interest in the last few decades. In this study, activated carbons (ACs) were produced via the carbonization of rice husk carbon (ash-less without silica), followed by chemical activation with KOH at 650 °C and 750 °C for 2 h/N₂ gas flow. Then, utilizing an improved Hummers’ method (Tour method) with modifications, graphene oxide (GO) samples were synthesized from the rice husk-based activated carbons as an alternative to graphite. Also, applying the Tour method, followed by a catalytic hydrothermal step, reduced graphene oxide (rGO) was obtained. FESEM and TEM images exhibited the formation of graphene oxide sheets after the oxidation of AC-KOH650 °C and AC-KOH650 °C. Furthermore, Raman, FTIR and UV-vis spectra characterized the presence of defects, oxygen functional surface groups and absorption bands, indicating the enhanced properties of graphene oxide prepared from graphite flakes through the improved Hummers’ method. In comparison to pure GO, the graphitized activated carbons from rice husk were successfully oxidized to GO samples and reduced to rGO after hydrothermal treatment with high yield and good quality.