High‐Entropy‐Alloy‐Nanoparticles Enabled Wood Evaporator for Efficient Photothermal Conversion and Sustainable Solar Desalination

High‐entropy‐alloy (HEA) nanoparticles with excellent photothermal conversion performances have been proven effective for solar steam generation abilities, but it remains a challenge to fabricate a macroscale evaporator through them. Here, assisting by the unique anisotropic porous structures of balsawood matrixes, a sustainable HEA‐nanoparticles‐balsawood (HEA‐BW) composited evaporator, in which two compositions construct an asymmetric surface wettability that the top surface of HEA nanoparticles acts as a hydrophobic photothermal area, while the bottom hydrophilic surface of balsawood allows for rapid water transportation, is assembled. The most efficient 8‐HEA‐BW realized an average optical absorption greater than 97% over the entire solar spectrum (250–2500 nm) and an excellent evaporation rate of 2.58 kg m −2 h −1 with a surface temperature of 80 °C under one sun irradiation. Surprisingly, a stable solar desalination performance of such composited evaporator can be observed in a 10‐cycles long‐term evaluation of the hypersaline water (20 wt% salinity) with an average evaporation rate of 1.65 kg m −2 h −1 .