FORMATION PROCESS AND STRUCTURE OF GRAPHITE OXIDE

Formation process of graphite oxide has been investigated by using a modified Staudenmaier method and an electrochemical one. The modified Staudenmaier method revealed that graphite oxide is formed via stage 1 graphite bi-intercalation compounds of HNO3 and H2SO4. On the other hand, the electrochemical method showed that graphite oxide is synthesized via stage 1 HClO4 graphite intercalation compound (GIC) in 11.6 M HClO4 solution and via stage 2 HClO4 GIC in 9.2 M HClO4 solution. Structure of graphite oxide was studied by fluorination of graphite oxide at 50-200-degrees-C. The main fluorination reaction is the substitution of hydroxyl group by fluorine atom. The c-axis repeat distances (I(c)) of fluorinated graphite oxides, prepared by both the Brodie and the modified Staudenmaier methods, were around 0.9 nm, which is close to that of stage 2 type poly(dicarbon monofluoride), (C2F)n. The in-plane lattice parameter a0 of graphite oxide increased toward that of (C2F)n by fluorination (0.251 nm), and decreased toward that of graphite itself by dehydration (0.246 nm). These results strongly support the (C2F)n-type structure model of graphite oxide,