Influence of order degree of coaly graphite on its structure change during preparation of graphene oxide

Coaly graphite is an important natural graphite resource that derived from coal under a natural process that associated with igneous intrusion. Flake graphite is usually used for the chemical synthesis of graphene oxide (GO), the main precursor for preparation of graphene, but few papers pay attention to preparing GO using coaly graphite. In this paper, four kinds of natural coaly graphite with different graphitization degrees were exposed to a modified Hummer’s oxidation method to prepare GO. The flake graphite sample was also used for comparison. The results showed that the structural change process from graphite to GO were significantly affected by the graphitization degree of the original coaly graphite. The relationship between yields of GO and graphitization degrees of the coaly graphite was explored. The mechanism of why the graphite with low graphitization degrees cannot be totally oxidized was proposed. Coaly graphite with a graphitization degree of higher than 80% was easier to be oxidized and yielded the same amount of GO as the flake graphite did, suggesting it is the potential substitute for the flake graphite to produce GO in bulk quantities.