Biomimetic Design of Photothermal/Electrothermal Fabric Composed of Carbon-Core/Nanorod-Array-Shell Fibers for Efficient All-Weather Seawater Evaporation

Abstract

Sunlight/electricity-driven thermal evaporation has been demonstrated as a promising strategy to obtain distilled water from seawater, but their practical applications are still limited by unsatisfactory photoabsorption and serious water-electrolysis during photothermal/electrothermal evaporation. Inspired by Paradisaeidae's feather and electric kettle, the biomimetic design of photothermal/electrothermal fabrics for realizing all-weather evaporation is reported. The fabrics are composed of fiber bundles with carbon fiber (CF) as the core and polypyrrole-decorated TiO₂ nanorod-array as a shell. Such CF/TiO₂/PPy fabric exhibits broad-spectral (280–2500 nm) photoabsorption with an efficiency of 95.5% due to the light-trapping effect, and it shows an evaporation rate (2.2 kg m⁻² h⁻¹) under 1 sun. Additionally, CF/TiO₂/PPy fabric demonstrates good electrothermal performance with suppressed water-electrolysis owing to the conductivity of CF and shielding effect of the nanorod-array-shell, resulting in high evaporation rate of 7.9 kg m⁻² h⁻¹ under 3 V. Importantly, by the combined effects of 1 sun and 3 V, CF/TiO₂/PPy fabric achieves an exciting evaporation rate of 9.1 kg m⁻² h⁻¹, even without solid-salt accumulation in the long-term evaporation process (10 h), benefiting from efficient photo/electrothermal conversion and sufficient water-supplementation from thermosiphon effect. Thus, the present biomimetic design of photothermal/electrothermal fabric supplies a new path to realize efficient all-weather seawater evaporation.