Gas‐phase Preparation of SO 3 ‐Graphite: Host‐Exchange and Exfoliation

The reaction of sulfur trioxide with graphite via gas phase led to an intercalation of a double layer of sulfur trioxide with a basal spacing of 11.1 Å. The SO 3 ‐graphite was obtained atom‐efficient as a single phase product without the need of purification. The increased basal space should facilitate an exfoliation by rendering the tactoids more shear labile. A further weakening of the attractive forces within a stack was done by the replacement of sulfur trioxide with the surfactant perfluorobutanesulfonic acid leading to a basal spacing of 16.8 Å. The large basal spacings were also preserved in suspension and no defects were created. The mechanical exfoliation with ultrasound predominantly broke the platelets. A rotor‐stator device offering high shear forces was found to exfoliate the platelets more gently but there was still a good number of very small particles.