Sustainable Biochar-Based Solar Absorbers for High-Performance Solar-Driven Steam Generation and Water Purification

Solar-driven interfacial steam generation is emerging as a green and sustainable technology for potential applications in sterilization, desalination, and water purification. Despite the encouraging progress to date, the solar absorbers of the interfacial steam generators generally are composed of costly and/or delicate nanostructures made from metal particles or semiconductor materials, which partially hinder their mass production for practical applications. Herein, the biomass Enteromorpha prolifera was successfully recycled to construct four biochar-based solar absorbers via a set of processing methods. The hydrophilic, hierarchically porous, and microtubular nanostructures of the carbonized E. prolifera contribute to synergistically efficient water pumping and steam generation of the solar absorbers. Inspired by the natural transpiration of trees, the two-dimensional interfacial steam generators based on the four solar absorbers attain good water evaporation rates of 1.1-1.3 kg m(-2) h(-1) and high photothermal conversion efficiencies of 80-84% under one sun. Specifically, the performance is among the best-performing solar steam generators constructed via biochar-based solar absorbers. The indoor and outdoor experiments demonstrate the first example of using green tide as a sustainable source for biochar-based solar absorbers and realizing cost-efficient and high-performance steam generation and clean water production.