Porous reduced graphene oxide/nickel foam for highly efficient solar steam generation.

Solar-driven water evaporation is considered to be an effective method for seawater desalination and wastewater purification. Here, we report a novel solar steam generation (SSG) system based on reduced graphene oxide (rGO)/nickel foam. Porous rGO foam acting as a photothermal conversion layer is fabricated by coating the rGO microsheets on the metallic nickel foam. The porous structure shows a rough surface, which can improve the harvest of light by scattering effect. On the other hand, the porous structure ensures the rapid flow of steam in the evaporation process. This SSG system based on rGO/nickel foam converts the absorbed solar energy into heat energy at the water-air interface and can effectively evaporate (∼83.4%) under low irradiation of 1 sun (1 kw m-2). The system shows great potential for the practical applications of water treatment at large-scale because of the high efficiency, simple preparation method and low cost.