Study of the Iodine Fixation over High Surface Area Graphite (HSAG-100) Under Mild Conditions

The controlled incorporation of halogens into carbon materials remains a challenge, particularly under mild and scalable conditions. In this work, we investigate the fixation of iodine on high-surface-area graphite (HSAG-100) using green solvents and moderate temperatures. Commercial HSAG was treated with iodine in aqueous and in organic media, with and without promoters, and characterized by XPS, LEIS, N2 physisorption, TGA/TPD, and XRD. The results reveal that iodine contents up to ~0.6 at% can be achieved, with incorporation strongly influenced by solvent and reaction time. XPS and LEIS confirmed the presence of C–I bonds, while BET analysis showed only moderate decreases in surface area and unchanged mesopore size distribution. Thermogravimetric and TPD analyses demonstrated the high thermal stability of C–I species, and XRD patterns ruled out intercalation between graphene layers. Collectively, these findings demonstrate that iodine can be covalently anchored to HSAG under mild conditions, preserving the graphitic structure and generating stable edge functionalities, thus opening a route for the design of halogen-doped carbons for catalytic and electrochemical applications.