Photochemically Induced Water Harvesting in Metal-Organic Framework

Harvesting water from air is one of the key environmental related issues facing humanity in recent years. In this study, we demonstrate that tha Ni-IRMOF74-III metal-organic framework structure attached with azopyridine molecules can potentially undergo photochemically induced cis/trans transition, leading to significant enhancement in the H2O working capacity. Specifically, grand canonical Monte Carlo simulations indicate an ultrahigh 0.20 kg kg(-1) of H2O working capacity at 25 degrees C adsorption and 65 degrees C desorption conditions. More importantly, given that the cis/trans switching is predominantly responsible for the discrepancy in the H2O uptake, even in the mild condition of 35 degrees C desorption (10 degrees C diurnal temperature swing), the H2O working capacity is still very high at 0.18 kg kg(-1). Our theoretical findings provide a blueprint to design the next generation water harvesting materials that can operate in natural conditions to expand its applicability in different regions around the world.