Lotus-Inspired Evaporator with Janus Wettability and Bimodal Pores for Solar Steam Generation

Solar thermal conversion (STC) evaporation is a practical and sustainable technology for seawater desalination and sewage abatement. However, both the limited evaporation efficiency and long-term conversion stability restrain its practical application. Herein, a lotus morphology-inspired biomimetic evaporator (MBE) with Janus wettability and bimodal pores is well designed for high-rate and enduring STC evaporation. Just like lotus leaves, the hydrophobic surface of the MBE cuts off the capillarity of water, hence achieving high-efficient salt resistance and solar absorption, while the hydrophilic substance provides fast water transportation. The bimodal-pore structures formed by incorporating lotus root-like mesopores into the 3D truss-like macropores effectively decrease density and thermal conductivity for self-floating and thermal regulation. This results in a low water vaporization enthalpy of 1846 J g−1, leading to a much higher evaporation rate at the same conversion efficiency. This work may open new avenues for developing high-performance evaporation systems.