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

Abstract

Atmospheric water harvesting (AWH) with metal-organic frameworks (MOFs) shows great potential for addressing water scarcity in arid regions, but current MOF based systems face limitations due to slow sorption kinetics and high energy demands.Here we present internally heatable, hierarchically porous, conductive MOF-coated carbon foams with dynamic water adsorption capacities of up to 0.20 g/g at 40 % RH. The composites can be regenerated with mild heating at 70 °C.This can be accompolished by either solar irradiation or joule heating, which allows for rapid desorption steps, reducing the time 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 and kilogram of adsorbent at 40 % RH.