Catalytic activity of 1,2-dichloroethane (DCE) dechlorinationwas compared for a number of graphene-based materials (carbon nanotubes, carbon nano flakes, nitrogen-doped carbon nano flakes,and fluorinated graphite) and diamond-based materials (nano diamond and synthetic diamond). Only diamond-based materials demonstrated dechlorination activity. Comparison of XPS datasuggested that either nitrogen- or oxygen-containing surface functional groups may be active in the dechlorination reactions.However, nitrogen containing groups were unlikely active sites because nitrogen-rich CNF-N demonstrated no activity in the DCE dechlorination. Oxygen-containing groups were also very unlikely to participate in the dechlorination, because the test reaction with 2-propanol showed rather similar composition ofoxygen-containing groups in CNT and ND, but only diamond-based materials were active in the dechlorination. However, the observed fact that only nano diamond materials were active in the dechlori-nation suggests that diamond structure played a crucial role in the conversion of DCE.