Stable superhydrophobic interfacial solar evaporator based on CuS@CDs hybrid photothermal composites towards ultrahigh-efficiency seawater evaporation

Superhydrophobic evaporator driven by solar energy is very promising in seawater desalination. However, low evaporation rate and photothermal conversion efficiency have greatly limited its practical applications. Here, we report a stable superhydrophobic solar evaporator with excellent photothermal performance for efficient saline evaporation. Specifically, CuS@carbon dots (CDs) composites are synthesized by a facile one-step hydrothermal approach. Then the composites are combined with fluorocarbon resin (FEVE) and sprayed on melamine sponge surface to create hierarchical structure to construct a superhydrophobic solar evaporator. Its excellent photothermal properties result from the synergistic effect of CuS and CDs in the composites. The temperature of the evaporator upper surface can rise to 125 °C within 3 min, and the evaporator presents high solar-vapor conversion efficiency (77.3%) and water evaporation rate (1.76 kg∙m−2∙h−1) under 1.5 Sun. Excitingly, for saline, the evaporation rate remains little changed (1.71 kg∙m−2∙h−1). Even after 10 test cycles (300 min), the evaporation rate of saline water is still able to reach 1.40 kg∙m−2∙h−1. Furthermore, the evaporator keeps hydrophobic property after being continuously immersed in high-concentration saline for 40 days, exhibiting excellent salt resistance. The prepared superhydrophobic evaporator with excellent photothermal performance has great potential in the fields of seawater desalination and sewage treatment. •Hybrid photothermal composites are synthesized by a facile one-step hydrothermal method.•A photothermal superhydrophobic surface can be created using the composites and resin.•A stable superhydrophobic solar evaporator is fabricated.•The photothermal composites endow the solar evaporator with high water evaporation rate.