Analysis of Chemical Structure of Reduced Graphite Oxide Synthesized in Different Reduction Atmospheres

In this work, a comparative study of thermally reduced graphite oxide (rGO) materials prepared by thermal exfoliation and reduction of graphite oxide (GO) at the temperature of 300 degrees C and 600 degrees C under different atmospheres (air, N-2, Ar, vacuum and H-2) was investigated through kinds of characterizations. The evaluation of chemical structure and quality of the rGOs by these various atmospheres is of high importance and is attempted side-by-side for the first time in this paper. The order of C/O ratio of rGOs obtained at 600 degrees C is that HH-rGO>HV-rGO>HAr-rGO approximate to HN-rGO>HA-rGO, whereas the effect of atmospheres on the rGOs obtained at 300 degrees C is not obvious. HH-rGO possesses better restoration of pi-conjugated structure and the increased average size of sp(2) carbon domains compared with other rGOs. rGOs with higher reduction degree result in the aggregation of rGO nanosheets and closer to graphite structure. TGA results proved the order of thermal stability is that HH-rGO>HV-rGO>HAr-rGO approximate to HN-rGO>HA-rGO. Additionally, HH-rGO could be easily exfoliated to few-layer nanosheets compared with others according to the AFM measurement. We believe that the findings will deepen our understanding of graphene obtained via thermal exfoliation and reduction method.