Water with three structures was compared for solar-steam generation: a) copper/silica nanoshells (CuSiN) having a plasmonic resonance in the visible region; b) thermal reduced graphene oxide (TrGO) having π-band optical transition; and c) an oxidized carbon foam (OCF) on the top allowing a localized heating. By using an open direct absorbing solar collector under simulated solar radiation, the evaporation rate (in kg/m 2 s) under 3 Suns was 2.1 x 10 -4 for pure water, while values of 5.1, 5.5 and 6.0 were reached for water with CuSiN, TrGO and OCF systems, respectively. Under natural sunlight (60 suns), for pure water an evaporation rate of 7.5 x 10 -4 was obtained after only 10 minutes of irradiation. Noteworthy, this value increased to 1.0 x 10 -2 for the system having the OCF while for all the nanoparticles systems the values were around 8.4 x 10 -3 .