Photoactive Metal-Organic Framework for Solar-Driven Atmospheric Water Harvesting in Arid Climates

Atmospheric water harvesting (AWH) using solar energy has gained significant attention; however, its application in arid climates poses challenges due to low relative humidity (RH) and reduced efficiency of conventional sorbents. metal-organic frameworks (MOFs) are a class of porous materials with an engineerable structure that have the ability to capture water even at very low RH.

Usually, the combination of photothermal materials with MOFs is used to desorb water sorbed by MOFs.

One of the challenges of this method is the reduction of MOF sorption capacity, which is very unfavorable, especially in arid climates.

Reducing the performance of sorbents in arid climates due to the blocking of sorption sites by dust is another challenge that has received little attention so far.

To address these challenges, this study evaluates the synthesis of a unique water-stable MOF with photothermal and photocatalytic (photoactive) properties (PAMOF), in addition to high water affinity.

Phthalocyanine and porphyrin ligands decorated with Ti and Cu ions, along with Yttrium (Y) and Erbium (Er) clusters, are considered as promising candidates.

Molecular modeling using density functional theory (DFT) will be conducted to guide the synthesis process, followed by experimental synthesis and characterization.

Subsequently, the samples will be evaluated in an AWH device to assess short-term efficiency and long-term maintenance in real conditions.

In addition to harnessing natural solar energy, the AWH experiments will involve the utilization of a custom-made solar simulator.

The SAWH device will be evaluated across a range of RHs, spanning from 10% to 90%, while considering the presence of artificial dust.

Through comparative analysis of existing research and with the aim of enhancing previously studied systems, this project endeavors to attain a daily water evaporation rate surpassing 4 kgwater/kgPAMOF under 1 sun and RH<30.