ACS Appl Mater Interfaces 2021 Apr 22. Epub 2021 Apr 22.
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Ammonia uptake by high-capacity and high-porosity sorbents is a promising approach to its storage and release, capture and mitigation, and chemical separation. Here, we examined the ammonia sorption behavior of several versions of an archetypal zirconium-based metal-organic framework (MOF) material, NU-1000-a meso- and microporous crystalline compound having the empirical formula (1,3,6,8-tetrakis(-benzoate)pyrene) Zr(μ-O)(μ-OH)(HO)(OH) with linkers and nodes arranged to satisfy a topology. Depending on the thermal treatment protocol used prior to sorption measurements, ammonia can physisorb to NU-1000 via hydrogen-bonding and London-dispersion interactions and chemisorb via Brønsted acid-base reactions with node-integrated proton donors (μ-hydroxos) and node-ligated proton donors (terminal hydroxos), via simple coordination at open Zr(IV) sites, or via dissociative coordination to Zr(IV) as NH and protonation of a node-based μ-oxo. Read More