Trace analyses of gaseous products formed during heat treatment of high stage H2SO4-GICs and expanded graphite Original Research Article

H2SO4-GICs samples prepared by different methods were heated to 1000 °C under flow of air using heating rates of 2, 10 and 20 K/min Gaseous products of decomposition were analysed using FTIR spectra recorded during the thermal process. It was detected that S–O species started evolving from graphite gallery above 500 °C, not depending on the method of GIC preparation. High expansion of H2SO4-GIC was observed when the intercalate evolved from the intercalated graphite before its abrupt oxidation to CO2. The disordered structure of graphite layers in H2SO4-GIC leads to easy release of S–O species without exfoliation effect. It was observed that using 2 K/min heating rate the time needed for intercalate to release from graphite gallery is shorter than that needed for its exfoliation. Therefore, the exfoliation process should be conducted using high heating rate.