MOF-integrated Bilayer Nanofibrous Membranes for Radiative-Cooling-Enhanced Atmospheric Water Harvesting

Abstract

Atmospheric water harvesting (AWH) is often limited by the efficiency trade-offs between water capture and release. Here, we developed a dual-layer nanofibrous membrane (PM-PC NFM) through electrospinning that synergistically couples nocturnal radiative cooling with diurnal photothermal heating. By integrating MIL-101(Cr) into a hierarchical porous network, the membrane achieves a mid-infrared emissivity of 0.90, enabling a sub-ambient cooling of 4.3 °C at night. This effect enhances water adsorption by 29%, increasing the equilibrium capacity to 0.62 g g⁻¹. During the day, the carbon black-doped layer provides a solar absorptance of 96%, raising the surface temperature to ~60 °C and enabling >95% water release within 20 minutes under 0.6 kW m⁻² solar flux. With a cumulative water yield exceeding 20 g over 10 cycles, this passive bilayer system offers a highly stable and electricity-free strategy for high-performance water harvesting in arid regions.