Node Distortions as a Means of Defect Engineering in Zr-Based MOFs
Till Schertenleib1,2, Timo M O Felder1, Nazanin Taheri1
1Institute of Chemical Sciences and Engineering (ISIC), École Polytechnique Fédérale de Lausanne (EPFL), 1950Sion, Switzerland.
Journal of the American Chemical Society
|August 12, 2026
Summary
Node dehydroxylation in zirconium-based metal-organic frameworks (Zr-MOFs) significantly enhances arsenic uptake. This study reveals cluster dehydroxylation, not missing linkers, as a key defect-engineering strategy for improved Lewis-acidic performance in Zr-MOFs.
Area of Science:
- Materials Science
- Chemistry
- Nanotechnology
Background:
- Defect engineering in zirconium-based metal-organic frameworks (Zr-MOFs) traditionally focuses on missing-linker defects.
- Node dehydroxylation, creating distorted nodes and coordinatively unsaturated Zr sites (Zr<0xE1><0xB5><0xA_US>), may significantly impact Zr-MOF properties.
- UiO-66 is a prominent Zr-MOF with potential applications in catalysis and adsorption.
Purpose of the Study:
- To investigate the distinct effects of node dehydroxylation and missing-linker defects in UiO-66.
- To challenge the prevailing "missing-linker" paradigm in Zr-MOF defect engineering.
- To establish cluster dehydroxylation as a viable defect-engineering strategy for enhancing Lewis-acidic performance.
Main Methods:
- Pair distribution function (PDF) analysis to probe local atomic structure.
- Thermogravimetric analysis (TGA) to quantify defect concentrations.
- Systematic manipulation of defects using rapid heat treatment (RHT) under humid flow and chemical treatments.
Main Results:
- Rapid heat treatment (RHT) under humid flow induced a structural transition from high-symmetry [Zr6O4(OH)4]12+ to distorted [Zr6O6]12+ nodes.
- The structural evolution towards distorted nodes significantly improved Arsenic(V) (As(V)) uptake.
- Increasing missing linkers, through chemical treatment or RHT of mixed-ligand frameworks, did not enhance performance.
Conclusions:
- Node dehydroxylation, leading to distorted Zr6 clusters, is a critical factor in enhancing As(V) uptake in UiO-66.
- The "missing-linker" paradigm may be less significant than previously assumed for certain Zr-MOF applications.
- Cluster dehydroxylation represents a promising defect-engineering strategy for optimizing Lewis-acidic properties in Zr-MOFs.
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