Enabling Continuous and Improved Solar-Driven Atmospheric Water Harvesting with Ti₃C₂-Incorporated Metal–Organic Framework Monoliths

Abstract

Solar-powered atmospheric water harvest (SAWH) with metal-organic frameworks (MOFs) represents one of the most sustainable, energy-efficient, and low-cost ways to alleviate water shortage stress in arid regions. However, the daily water productivity of previously developed SAWH devices remains low as they are merely allowed to be operated in batch mode and complete one water harvest cycle every day. This inevitably makes it rather challenging to deploy MOF-based SAWH for water production at scales. To overcome this challenge, MXene Ti₃C₂-incorporated UiO-66-NH₂ (TUN) cylindrical monoliths (13 mm diameter, 4 mm thickness) with vertically aligned porous networks have been prepared and exhibited greatly enhanced solar heating capacity and atmospheric water adsorption/desorption kinetics. Using TUN monoliths as atmospheric water adsorbents, a novel SAWH device containing a flippable adsorbent stage with dual TUN monolith layers attached on both sides has been fabricated. Such a novel design enables the prototype to produce water in a continuous mode under sunlight irradiation, delivering 57.8 mL_H₂O kg_MOF^-1 h^-1 of water productivity in a simulated indoor arid environment (20% relative humidity, 298 K). This is the first exploration in continuous water production with MOF-based SAWH, demonstrating a promising way to achieve scalable and low-cost SAWH in arid areas.