Bioinspired 1T-MoS2-based aerogel beads for efficient freshwater harvesting in harsh environments

Abstract

Freshwater scarcity is one of the most critical issues worldwide, particularly in arid regions, stemming from population growth and climate change. Inspired by the hydrophilic bump structures of desert beetles, 1T-MoS₂-based aerogel beads with porous structures and CaCl_2-crystal loading (termed as MoAB-m@CaCl₂-n) were prepared for freshwater harvesting. Metallic-phase MoS₂ nanospheres exhibit excellent photothermal conversion abilities, facilitating solar-driven water desorption and evaporation. Owing to the synergistic effect of its localized surface features, hydrophilic groups, and dispersive CaCl₂ particles, MoAB-2@CaCl₂-2 efficiently harvests water from atmosphere with a superior moisture adsorption capacity (0.18-0.82 g g^-1) at a wide range of relative humidity (10 %-70 %). Under one-sun illumination, MoAB-2@CaCl₂-2 demonstrates an outstanding solar-driven water evaporation rate of 2.25 kg m^-2h^-1. The water evaporation rate from soil (water content = 20 %) is 1.19 kg m^-2h^-1, which is sufficient for sustainable freshwater generation from the soil in arid regions. More importantly, the multifunctional MoAB-2@CaCl₂-2-based homemade freshwater generation prototype delivers a certain amount of water harvesting (0.99 g g^-1 day^-1) on a rainy day and provides an impressive daily freshwater yield (53.7 kg m^-2) under natural sunlight. The integrated device exhibits excellent efficiency and practicality and offers a feasible method for freshwater harvesting in harsh environments.

Keywords: Atmospheric water adsorption; Molybdenum disulfide; Soil Freshwater generation; Solar evaporation.