Biomass-Derived Bilayer Solar Evaporator with Enhanced Energy Utilization for High-Efficiency Water Generation

Solar-driven evaporation has been recognized as a promising approach to address global crises of drinking water via virtue of abundant and green solar energy. However, a great challenge still exists for achieving efficient usage of solar energy combined with fast water evaporation. Here, a double-structural solar evaporator consists of an upper copper sulfide (CuS) agar-based aerogel and a bottom molybdenum carbide/carbon (MoCC) composite of cotton fibers-derived aerogel (CuSAA/MoCCFA), which is constructed for solar evaporation. The CuS layer performs as a solar-thermal converter with efficient light adsorption and prominent thermally localized ability, while the bottom layer (superhydrophilic porous aerogel) guarantees sufficient water transportation and excellent thermal insulation. The fully integrative solar evaporator has an attractive water evaporation rate of 2.44 kg m^-2 h^-1 with a superb solar-thermal conversion efficiency of 92.77% under 1 sun illumination. More notably, the bilayer aerogel exhibits long-term durability in high-salinity media during solar-driven desalination. In addition, a solar absorber assisted with low-temperature phase change materials comprise the solar evaporation system, which is aimed at solar-thermal energy storage and reutilization for conquering solar intermittence. Such superior performance of a comprehensive solar desalination system provides a new avenue for highly efficient and suitable clean water production under natural sunlight conditions.