A Fine-Tuned Metal–Organic Framework for Autonomous Indoor Moisture Control

Conventional adsorbents, namely zeolites
and silica gel, are often
used to control humidity by adsorbing water; however, adsorbents capable
of the dual functionality of humidification and dehumidification,
offering the desired control of the moisture level at room temperature,
have yet to be explored. Here we report Y-shp-MOF-5,
a hybrid microporous highly connected rare-earth-based metal–organic
framework (MOF), with dual functionality for moisture control within
the recommended range of relative humidity (45%–65% RH) set
by the American Society of Heating, Refrigerating, and Air-Conditioning
Engineers (ASHRAE). Y-shp-MOF-5 exhibits exceptional
structural integrity, robustness, and unique humidity-control performance,
as confirmed by the large number (thousand) of conducted water vapor
adsorption–desorption cycles. The retained structural integrity
and the mechanism of water sorption were corroborated using in situ
single-crystal X-ray diffraction (SCXRD) studies. The resultant working
water uptake of 0.45 g·g–1 is solely regulated
by a simple adjustment of the relative humidity, positioning this
hydrolytically stable MOF as a prospective adsorbent for humidity
control in confined spaces, such as space shuttles, aircraft cabins,
and air-conditioned buildings.