Previous uSR measurements on chemically produced graphene showed that, apart from a slowly relaxing graphite-like fraction, approximately 40% of the implanted muons are trapped by the graphene hydrogenated defects (vacancies), which give rise to a CHMu entangled state. With this measurements we propose to extend this investigation to metal decorated graphenes, recently synthesized in our laboratory with the aim to produce new materials for the reversible storage of hydrogen. We would like to test how the added metal atoms are efficient in trapping muonium and how they will compete with the graphene defects.