Tungsten-hydrogen complexes on graphene on Ir(111)

W and W-H complexes on graphene on Ir(111) were studied by means of low temperature scanning tunneling microscopy. H is found to coadsorb at the sample surface during W evaporation. Five different W-related structures on graphene on Ir(111) were found and characterized. They are identified as WHn, with , as shown by electric field induced dehydrogenation. They exhibit a number of peculiar effects, such as electric field induced shifts of spectroscopic features as well as reversible switching and charging effects. In addition, two different structures of H on Ir(111) were characterized.