Surface modification of high-surface area graphites by oxygen plasma treatments

Two types of high-surface area graphite having different specific surface areas (HSAG100 and HSAG300) were treated in a low-pressure microwave discharge oxygen plasma for 3 and 10 min. The physico-chemical properties at surface scale of the resulting materials were investigated by N-2 physisorption, Raman spectroscopy, temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). For both materials, an increase of the degree of graphitic order was observed following the longer oxygen plasma exposure. Likewise, the 10-min plasma treatment gave place to surface-functionalized materials without compromising their thermal stability and aromatic network. Particularly, for HSAG100, the longer plasma exposure contributed to the development of an edge surface-functionalized graphite. In the case of as-received HSAG300, the presence of a mechanically damaged sub-surface ascribable to the milling process could be evidenced.