A flowerlike sponge coated with carbon black nanoparticles for enhanced solar vapor generation

Interfacial solar-driven water evaporation is emerging as a new and promising technology due to its great potential in utilizing solar energy for various applications such as desalination, purification and sterilization. Here, we propose a model to enhance the generation of solar steam by adjusting the surface topography of a sponge-based solar evaporator. A flowerlike solar vapor generation system, which is composed of recycled low-cost materials including polyurethane sponge, carbon black nanoparticles, cotton strip and polystyrene foam, is reported. An evaporation rate of 2.31 kg m−2 h−1 is obtained under 1 sun illumination, which is attributed to the increased actual surface area, efficient light absorption and satisfactory heat insulation. In addition, this solar-driven vapor generation device exhibits excellent water desalination performance. Ion concentrations (Na+, Mg2+, K+ and Ca2+) of distilled water decrease far below the normal concentration set by WHO for drinking water. This work provides an alternative way to achieve highly efficient solar vapor generation for desalination and purification of seawater and industrial sewage.