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

Abstract

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.