Electrically conductive MOF@carbon foam composites for atmospheric water harvesting through internal Joule heating and light irradiation

Abstract

Atmospheric water harvesting (AWH) with microporous adsorbents shows great potential for addressing water scarcity in arid regions, but current systems face limitations due to slow sorption kinetics and high energy demands. Here, we present a proof of concept for internally heatable, hierarchically porous, conductive MOF–coated carbon foams with dynamic water adsorption capacities of up to 0.20 g g⁻¹ at 40% RH. The percolating macroporous carbon foam serves as the backbone of the composites, facilitating simultaneous heat and mass transport. Regeneration of the composites is possible with mild heating at 70 °C. This can be accomplished by either solar irradiation or Joule heating, which allows for rapid desorption steps, reducing the duration of the desorption step by up to 51% compared to flushing with helium, resulting in short sorption cycles between 46 and 178 minutes. In continuous operation, the composites can potentially collect between 1.5 and 2.2 litres of water per day per kilogram of adsorbent at 40% RH.