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 °C and 600 °C under different atmospheres (air, N2, Ar, vacuum and H2) 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 °C is that HH‐rGO>HV‐rGO>HAr‐rGO≈HN‐rGO>HA‐rGO, whereas the effect of atmospheres on the rGOs obtained at 300 °C is not obvious. HH‐rGO possesses better restoration of π‐conjugated structure and the increased average size of sp2 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≈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. In this work, the effect of atmospheres and temperature on the chemical structure and quality of the rGOs was investigated. The order of C/O ratio and the order of thermal stability of rGOs were obtained through XPS and TGA results, respectively. The defect level of of rGOs (300 °C) under different atmospheres is similar. The ID/IG value for HH‐rGO (0.90) obviously decreased. Additionally, HH‐rGO could be easily exfoliated to few‐layer nanosheets compared with others according to the AFM measurements. [ABSTRACT FROM AUTHOR]