Mussel-inspired photothermal synergetic system for clean water production using full-spectrum solar energy

Abstract Facing the long-term shortage of global water resources, the use of solar energy for desalination and wastewater treatment has always been the focus of human exploration. Here, inspired by mussel-chemistry, we designed a functional photothermal-photocatalysis system based on Cu foam with abundant marigold-like CuO nanoflowers and Prussian blue (PB) nanoparticles. This superhydrophilic composite material (CuO@PDA/PB) has superior full-spectrum solar energy absorption (300–2500 nm), which achieved interfacial heating under solar radiation to generate stable water vapor. Besides, superhydrophobic CuO@PDA/PB with self-floating properties and Janus CuO@PDA/PB with asymmetric wettability and anti-turnover ability were prepared to systematically compare the effects of wettability on solar energy utilization. We conclude that the hydrophilicity of the sample and the strong capillary pumping effect are more conducive to water transmission, and the superhydrophilic CuO@PDA/PB has a higher evaporation rate (1.39 kg m–2 h–1) and efficiency (87.10%) than other samples under 1.0 sun. Importantly, the superhydrophilic CuO@PDA/PB with excellent salt-tolerance and antifouling property can also be used for the purification of the saline solution, oily wastewater and dyeing effluents via the solar-driven water evaporation. Moreover, CuO@PDA/PB possessed superior adsorption and photocatalytic degradation ability for the organic dyes in dyeing wastewater. Therefore, this solar-driven superwetting functional material provides an expandable and cost-effective platform for seawater desalination and sewage purification.