Direct and efficient conversion from low-quality graphite to high-quality graphene nanoplatelets

Abstract

Low-quality graphite (L-graphite), containing various impurities (e.g., metals and inorganics), can be directly and efficiently converted into high-quality iodine-doped graphene nanoplatelets (HIGnPs) via mechanochemical ball-milling in the presence of iodine (I2) with subsequent work-up procedures. Despite using L-graphite, the resultant HIGnPs show high-quality characteristics, including large specific surface area (969 m2 g−1), lower metallic residues, and well-maintained graphitic structure. In addition, HIGnPs display remarkable electrocatalytic performance for oxygen reduction reaction (ORR), involving benefits such as higher selectivity, longer-term stability, and better tolerance to methanol crossover/CO poisoning effects. Therefore, simple mechanochemical ball-milling in solid state can produce high-quality graphene nanoplatelets in large quantity at low-cost for commercialization, regardless of the initial quality of the graphite.