Research progress on novel solar steam generation system based on black nanomaterials

Among all the renewable energy sources, solar irradiation has the greatest potential to meet the world's future energy demands. The solar-driven generation of water steam has emerged as a promising route for solar energy utilization in the fields of global water cycle, seawater desalination, high-temperature sterilization, and wastewater treatment. A typical solar thermal energy converting process involves heat harvesting by solar thermal absorber and heat stimulating the evaporation of water via sensible heat and latent heat. In this review, the novel direct solar steam generation systems based on black nanomaterials are presented. These direct solar steam production systems can be categorized into the following two types: nanofluid-based evaporation systems and suspended interface evaporation systems. We describe the physical model and experimental results of these systems, as well as the determination of optimal evaporation system design according to excellent evaporation performance. Finally, we elucidate the dominant factors influencing the evaporation efficiency and propose improved approaches to further increase solar steam production efficiency for the discovery of practical applications.