Role of Peroxide Ions in Formation of Graphene Nanosheets by Electrochemical Exfoliation of Graphite

This study demonstrates a facile, mild and environmentally-friendly sustainable (soft processing) approach for the efficient electrochemical exfoliation of graphite using a sodium hydroxide/hydrogen peroxide/water (NaOH/H2O2/H2O) system that can produce high-quality, anodic few-layer graphene nanosheets in 95% yield at ambient reaction conditions. The control experiment conducted using NaOH/H2O revealed the crucial role of H2O2 in the exfoliation of graphite. A possible exfoliation mechanism is proposed. The reaction of H2O2 with hydroxyl ions (HO-) leads to the formation of highly nucleophilic peroxide ions (O-2(2-)), which play a crucial role in the exfoliation of graphite via electrochemical-potential-assisted intercalation and strong expansion of graphite sheets.