Monolithic Zirconium-based Metal-Organic Frameworks for Energy-Efficient Water Adsorption Applications.

Space cooling and heating, ventilation and air conditioning (HVAC) accounts for roughly 10% of global electricity use and is responsible for ca. 1.13 gigatonnes of CO 2 emissions annually. Adsorbent-based HVAC technologies have long been touted as an energy-efficient alternative to traditional refrigeration systems. However, thus far, no suitable adsorbents have been developed which overcome the drawbacks associated with traditional sorbent materials such as silica gels and zeolites. Metal-organic frameworks (MOFs) offer order of magnitude improvements in water adsorption and regeneration energy requirements. However, the deployment of MOFs in HVAC applications has been hampered by issues related to MOF powder processing. Herein, we develop three high-density, shaped, monolithic MOFs (UiO-66, UiO-66-NH 2 and Zr-Fumarate) with exceptional volumetric gas/vapor uptake - solving previous issues in MOF-HVAC deployment. We visualized the monolithic structures across the mesoporous range using SAXS and lattice-gas models, giving accurate predictions of adsorption characteristics of the monolithic materials. We also demonstrate that a fragile MOF such as Zr-fumarate can be synthesized in monolithic form with a bulk density of 0.76 gcm -3 without losing any adsorption performance, having a coefficient of performance (COP) of 0.71 with a low regeneration temperature (≤ 100 ᵒC). This article is protected by copyright. All rights reserved.