High-yield solar-driven atmospheric water harvesting of metal-organic-framework-derived nanoporous carbon with fast-diffusion water channels.

Abstract

Solar-driven, sorption-based atmospheric water harvesting (AWH) offers a cost-effective solution to freshwater scarcity in arid areas. Creating AWH devices capable of performing multiple adsorption-desorption cycles per day is crucial for increasing water production rates matching human water requirements. However, achieving rapid-cycling AWH in passive harvesters has been challenging due to sorbents' slow water adsorption-desorption dynamics. Here we report an MOF-derived nanoporous carbon, a sorbent endowed with fast sorption kinetics and excellent photothermal properties, for high-yield AWH. The optimized structure (40% adsorption sites and ~1.0 nm pore size) has superior sorption kinetics due to the minimized diffusion resistance. Moreover, the carbonaceous sorbent exhibits fast desorption kinetics enabled by efficient solar-thermal heating and high thermal conductivity. A rapid-cycling water harvester based on nanoporous carbon derived from metal-organic frameworks can produce 0.18 L kgcarbon-1 h-1 of water at 30% relative humidity under one-sun illumination. The proposed design strategy is helpful to develop high-yield, solar-driven AWH for advanced freshwater-generation systems.