“…This is superior to other functional groups like F, N and O, which either destroy the structural integrity of the system or have a much weaker binding strength. 54,55 Thus, similar to the case of hydrogenated graphene, 56 when these MSi 2 N 4 nanosheets are exposed to hydrogen plasma surroundings, highly H-covered surfaces will be formed. Following previous studies on hydrogenated graphene and TMDs, 45,46 we mainly pay attention to the semi-and fully-hydrogenated MSi 2 N 4 nanosheets, i.e.…”