Enhancing Atmospheric Water Harvesting of MIL‐101 (Cr) MOF Sorbent with Rapid Desorption Enabled by Ni─Ni3S2 Photothermal Bridge

Abstract

AbstractMetal–organic frameworks (MOFs) have emerged as leading candidates for atmospheric water harvesting (AWH). Despite their high water uptake capacity, challenges persist in effective solar‐driven desorption for water collection. Addressing this, a photothermal bridge is introduced by in situ growth of Ni₃S₂ coating on a thermally conductive nickel mesh, enhancing heat transfer to the MOF and accelerating desorption kinetics. MIL‐101 (Cr) MOF in bulk form (BMOF) is bonded to the lightweight Ni─Ni3S2 mesh using adhesive, forming a dual‐layer Ni─Ni₃S₂ mesh/BMOF assembly. This hybrid retains a high water uptake of ≈0.63 g g⁻¹ at 60% relative humidity (RH) with superior sorption kinetics. Photothermally driven heat transfer from Ni─Ni₃S₂ to BMOF achieves complete water desorption within 40 min under 1 kW m−2. Compared to other configurations like foil, granules, and foam, the mesh‐based hybrid has the highest single‐cycle adsorption–desorption kinetic of 3.18 × 10⁻3 g g⁻¹ min⁻¹. Additionally, the hybrid demonstrates exceptional hydrothermal stability over 50 cycles and maintains morphological stability with airflow, ensuring consistent performance. Heat transfer simulations confirm the thermal distribution across the Ni─Ni₃S₂ mesh/BMOF, corroborating the rapid and uniform desorption. This approach paves the way for efficient AWH in high‐RH, water‐scarce regions by enhancing desorption kinetics through solar energy.