posted on 2024-03-12, 00:04authored byFanrui Sha, Haomiao Xie, Kent O. Kirlikovali, Wei Gong, Yongwei Chen, Omar K. Farha
Defect engineering proves to be a highly effective approach
for
introducing additional open metal sites and porosity into metal–organic
frameworks (MOFs), thereby enhancing their gas storage, separation,
and chemical catalysis capabilities. However, characterizing defective
MOFs, which often exhibit nonuniform pores, presents a significant
challenge. While probe molecules have been widely utilized to explore
the physical and chemical properties of MOF pores, their application
has predominantly been limited to gas- or vapor-phase molecules. In
this study, we present a novel approach by employing a size-selective
fluorescent protein probe to characterize macroporous defects induced
by tartaric acid in a zirconium-based MOF, NU-1000. The spatial visualization
of defects using a hemoglobin-based fluorescent probe allows for the
identification of distinct structural weak points and defect formation
mechanisms in NU-1000 crystallites prepared by various methods. In
addition to confirming findings from conventional MOF characterization
methods, such as gas sorption isotherms and powdered X-ray diffraction
analysis, the hemoglobin-based protein probe unveils structural nuances
overlooked by many traditional characterization techniques.