Rational Design of a High Performance and Robust Solar Evaporator via 3D‐Printing Technology

Abstract Utilizing the broad‐band solar spectrum for sea water desalination is a promising method that can provide fresh water without sophisticated infrastructures. However, the solar‐to‐vapour efficiency has been limited due to the lack of a proper design for the evaporator to deal with either a large amount of heat loss or salt accumulation. Here, these issues are addressed via two cost‐effective approaches: I) a rational design of a concave shaped supporter by 3D‐printing that can promote the light harvesting capacity via multiple reflections on the surface; II) the use of a double layered photoabsorber composed of a hydrophilic bottom layer of a polydopamine (PDA) coated glass fiber (GF/C) and a hydrophobic upper layer of a carbonized poly(vinyl alcohol)/polyvinylpyrrolidone (PVA/PVP) hydrogel on the supporter, which provides competitive benefit for preventing deposition of salt while quickly pumping the water. The 3D‐printed solar evaporator can efficiently utilize solar energy (99%) with an evaporation rate of 1.60 kg m –2 h –1 and efficiency of 89% under 1 sun irradiation. The underlying reason for the high efficiency obtained is supported by the heat transfer mechanism. The 3D‐printed solar evaporator could provide cheap drinking water in remote areas, while maintaining stable performance for a long term.