Simultaneous engineering on absorption window and transportation geometry of graphene-based foams toward high-performance solar steam generator

Graphene-based materials are frequently highlighted as the candidate for solar steam generation (SSG) because of their advantages such as high solar absorption, tunable structure and low cost. However, graphene itself is not a “perfect” absorber for full solar spectrum and cannot efficiently transport water on its surface due to its intrinsic physicochemical characteristics. Here we designed and synthesized a graphene foam in a three-dimensional (3D) interconnected porous structure with silicon carbide nanoparticles anchored on graphene surfaces. The systematical characterizations confirm that the hybrid structure extends the solar absorption window of graphene in full solar spectrum; and moreover, the in situ environmental scanning electron microscopy (ESEM) experiments suggest the incorporation of SiC nanoparticles on two-dimensional graphene surface improves the condensation and transportation kinetics of water in the foam. As a result, the SSG device based on the graphene-SiC composite demonstrates an improved energy conversion efficiency up to 95% under one sun illumination compared with those of previous reported graphene-based materials. The findings may shed new light on the technologies for solar-energy-water nexus.