Self-floating solar evaporator based on kapok fiber for high-performance solar steamgeneration

The nanostructure of materials plays a key role in interfacial solar vapor generation. Traditional approaches for optimizing interfacial evaporation rely on the external devices to enable floating on water. However, how to unlock the self-floating ability of absorbers for solar interfacial evaporation have not been taken into account. Here, we propose a self-floating absorber based on kapok fibers, which possess large hollow structure and hydrophobicity to enable this absorber float on water without assistance. Gold nanoparticles (AuNPs) were loaded on kapok fibres by in-situ synthesis and showed an extended adsorption (74.7%) wavelength ranging from 280 to 2500 nm. Both the hollow structure of kapok fibres and the thermal localization effect of AuNPs sustaintially enhance the solar interfere vapor generation effect (4 kW m−2, up to 89%). Also, Each cycle test was carried out under 1 h irradiation. The AuNPs/kapok membrane exhibited stable cycling performance, which maintained an evaporation rate of 6.98 kg m−2 h−1 over 10 times without performance decrease. These results provide new insights for design of advanced photothermal conversion materials with biomass as supporting material, We expect this as-prepared membrane can be used for a range of applications, such as solar interference steam generation, desalination and disinfection, to name a few.