Environmentally Friendly and Efficient Hornet Nest Envelope-Based Photothermal Absorbers

[Image: see text] Water shortage is a critical global issue that threatens human health, environmental sustainability, and the preservation of Earth’s climate. Desalination from seawater and sewage is a promising avenue for alleviating this stress. In this work, we use the hornet nest envelope material to fabricate a biomass-based photothermal absorber as part of a desalination isolation system. This system realizes an evaporation rate of 3.98 kg m(–2) h(–1) under one-sun illumination, with prolonged evaporation rates all above 4 kg m(–2) h(–1). This system demonstrates a strong performance of 3.86 kg m(–2) h(–1) in 3.5 wt % saltwater, illustrating its effectiveness in evaporation seawater. Thus, with its excellent evaporation rate, great salt rejection ability, and easy fabrication approach, the hornet nest envelope constitutes a promising natural material for solar water treatment applications.