Hydrogen plasma treated nanodiamonds lead to an overproduction of hydroxyl radicals and solvated electrons in solution under ionizing radiation

International audienceIn numerous fields of application (environmental remediation, catalysis, nanomedicine), production ofhydroxyl radicals and solvated electrons by nanomaterials is a cornerstone. Through a very sensitive,nanoparticle-compatible, coumarin-based protocol, we quantified hydroxyl radicals in solution whenhydrogenated (H-ND) and oxidized (Ox-ND) detonation nanodiamonds were irradiated by MeV photons.We highlighted a blatant difference between the two surface chemistries as only H-ND led to 50% moreradicals, for irradiation doses and ND concentrations relevant in nanomedicine. For the first time, we alsoquantified solvated electrons after keV irradiation of both suspensions and showed that in the presenceof H-ND, hydroxyl radicals and solvated electrons were available in solution in equivalent and higheramounts than in water only. This asks the question of the mechanisms at stage and beside the negative/positive electron affinity hypothesis usually mentioned, we proposed, as for other nanomaterials, thatinterfacial water could play an essential role in radicals’ production in solution when detonation H-NDare irradiate