A robust photoelectrothermal evaporator with hierarchical NiCo2S4 nanowires grown on nickel foam for a high rate of clean water production

Abstract

Interfacial solar steam generation (ISSG) stands as a promising technology in addressing global water scarcity, stemming from reasons like global warming and population growth. Despite its potential, ISSG faces challenges due to varying weather conditions and solar intensity fluctuations. To overcome these limitations, a novel approach by integrating photothermal and electrothermal Joule-heating effects is introduced in this study for a high-efficiency and salt-resistant all-weather, all-day seawater desalination. Hierarchical NiCo2S4 nanowires are fabricated on a Ni-foam (NCNNF) using a facile two-step hydrothermal method. Under photothermal evaporation, the NCNNF evaporator produces an evaporation rate of 1.57 ± 0.08 kg m−2 h−1 with an evaporation efficiency of 77 % under 1sun illumination with good anti-fouling ability. In a simple water desalination setup, the surface temperature of the evaporator in a wet state reaches ∼63.5 ± 0.25 °C within 10 min by applying an input voltage of 1 V and 1sun irradiation condition, yielding an outstanding evaporation rate of 21.3 ± 3.6 kg m−2 h−1 and evaporation efficiency of 80 %. The proposed evaporation device can resist salt accumulation on the evaporator surface in long-term operations. The present results would be utilized in developing high-performance Joule-heating assisted solar water evaporation devices, especially for all-day, all-weather desalination to produce clean potable water.