A low-cost lotus leaf-based carbon film for solar-driven steam generation

Abstract Solar-driven interfacial evaporation has attracted much attention owing to its potential for addressing the shortage of freshwater. Low-cost and high-efficiency photothermal conversion materials are the key to the application. A low-cost lotus leaf-based carbon film (LLC) for use as a photo-to-heat conversion medium for solar-driven steam generation was prepared by the simple vacuum filtration of LLC obtained at a carbonization temperature of 800 oC using a porous fibrous filter paper. In a laboratory-made solar steam generation real-time test system using commercial polystyrene foam as the insulation layer and the LLC film on porous fibrous filter paper as the water transport path, the LLC film exhibits a solar-driven water evaporation rate of 1.30 kg/m2 h and a solar-vapor conversion efficiency of 77.5%. The LLC film also shows excellent performance in seawater desalination and sewage purification. The work provides a possible route for the use of low-cost and environmentally friendly biomass-based carbon materials in solar-driven steam generation.