SiO2@MXene-based fabric featuring low heat loss for high-efficiency solar-driven freshwater production

Interfacial solar-driven steam generation is a promising approach for addressing the global freshwater crisis. However, the lower evaporation rate owing to high heat-loss is still a primary obstacle to commercialization. Given the high transmittance to solar radiation and superior isolation to thermal radiation of SiO2 aerogel, herein we design a hanging SiO2@MXene-based fabric (SMF) evaporator for high-efficiency solar-driven freshwater production. Under light irradiation, the internal MXene-based fabric with high solar absorption can rapidly convert solar radiation into heat-energy, while the outermost transparent SiO2 aerogel with excellent thermal insulation performance can efficiently prevent the internal heat-quantity from escaping outward. As such, the solar-to-thermal is well confined within the MXene-based fabric, endowing SMF with low heat loss towards surroundings. An evaporation rate as high as 1.87kg•m−2•h−1 along with heat-loss as low as 5.9% is achieved under 1-sun, superior to other prior evaporators. Better yet, neither a decrease in evaporation rate nor fouling on SMF is observed even when treating high-salinity brine. This work provides new insights into reducing heat loss to enhance evaporation rate during solar desalination.