Photothermal CuS@SiO2 nanocomposites for solar-driven anti-icing/deicing and synchronous evaporation and photocatalysis

Solar energy-driven water purification is a highly promising technique to address pollution crisis and freshwater scarcity. Herein, we developed a novel CuS@SiO2 nanocomposite for anti-icing/deicing and simultaneous seawater evaporation and photodegradation of dyes. The CuS@SiO2 nanocomposites were obtained via in situ hydrolysis of tetraethyl orthosilicate (TEOS) in the presence of as-synthesized CuS nanoplates, followed by surface modification with hexamethyldisilazane. A self-floating photothermal-photocatalytic dual-functional evaporator was achieved by incorporating a melamine foam (MF) with the CuS@SiO2 nanocomposite, where CuS acted as a photocatalyst and strong photothermal component while SiO2 helped construct porous architecture with controlled wettability. The representative evaporator with a Janus wettability of superhydrophilicity-superhydrophobicity displayed excellent simultaneous evaporation and photocatalytic capability, with a high water evaporation rate of over 1.962 kg m-2 h-1 and dye degradation of around 100% under 1.0 sun illumination (1 kW m-2). Furthermore, the as-sprayed superhydrophobic photothermal CuS@SiO2 coating showed excellent anti-icing/deicing performance owing to its strong photothermal conversion capability and superhydrophobicity. The procedures described herein enable convenient and novel strategies to fabricate multi-functional nanocomposites and coatings with controlled surface wettability, shedding light on promising potentials in energy conversion applications for solar-driven freshwater generation, sewage purification, photocatalysis and anti-icing/deicing.