Monolithic integrated evaporator for enhanced all-weather seawater desalination via solar-thermal and Joule-heating dual-mode interfacial evaporation

A monolithic mesh evaporator with dual-mode heating was developed for all-weather desalination. • CuS nanosheets and CNTs achieve complementary broad-spectrum absorption (∼92%). • The hierarchical porous structure reduces evaporation enthalpy and accelerates vapor escape. • Solar-electric collaboration achieves 24 h continuous freshwater production. Solar-driven interfacial water evaporation is attracting increasing attention as a promising environmentally-friendly solution to freshwater scarcity. However, achieving efficient and uninterrupted solar-driven seawater desalination remains challenging due to intermittent sunlight and salt fouling. Herein, a monolithic integrated evaporator of a mesh composite (CNTs-CuS-CuO/Cu) was fabricated for all-weather seawater desalination via dual-mode (solar-thermal and Joule-heating) interfacial evaporation. A hierarchical microporous structure was obtained by combining CuS nanosheets grown in situ with sprayed carbon nanotubes (CNTs). This design offers three key advantages: (1) CuS enhances near-infrared absorption, complementing the visible-light absorption of CNTs for efficient solar capture (an average light absorbance of approximately 92%). (2) The porous network enlarges the evaporation area, facilitates rapid vapor escape, and provides ample water transport channels, effectively reducing the water evaporation enthalpy. (3) The conductive copper mesh enables low-voltage Joule-heating, allowing for continuous fresh water production at night or under weak sunlight. This “solar-thermal and Joule-heating” synergy ensures operability, overcoming weather dependency. The obtained results demonstrated that the CNTs-CuS-CuO/Cu mesh composite can produce a daily freshwater yield exceeding Under natural sunlight, the CNTs-CuS-CuO/Cu mesh composite achieved a high daily freshwater output of more than 32.7 kg·day ⁻1 under natural sunlight. The total ion concentration of the fresh water is as low as 19 ppm, which is well below the World Health Organization (WHO) drinking water threshold of 500 ppm. This work presents a promising strategy for designing high-performance, anti-fouling, and all-weather evaporators for practical seawater desalination. Download: Download high-res image (328KB) Download: Download full-size image