Flexible 2D@3D Janus evaporators for high-performance and continuous solar desalination

Interfacial solar desalination has been widely considered as one of the promising pathways to alleviate worldwide water scarcity . An ideal evaporator for interfacial solar desalination in practical use requires facile preparation, high efficiency, low cost, flexibility, excellent salt resistance, and good stability, etc. This work presents the high-performance solar desalination by using a flexible 2D@3D Janus evaporator, which is prepared via a facile two-step dipping strategy. Due to the hydrophobicity-induced interfacial layer , the top layer of the Janus evaporator plays the role of effective solar harvesting and solar-to-heat conversion, and salt rejection, while the hydrophilic bottom layer accounts for efficient heat localization and continuous water supply. Consequently, under the low solar irradiations (1.0–2.5 kW m −2 ), the Janus evaporator exhibits high-performance freshwater output (1.2–3.1 kg m −2  h −1 ), high-efficiency solar conversion (90.67%–94.62%), and excellent desalination performance. In addition, this Janus evaporator shows well flexibility and structural stability, good cost effectivity and long-term salt resistance over 7 days for continuous steam generation. By combining these advantages, this Janus evaporator holds great promise in solar-driven water purification , sterilization, and so forth.