Quantitatively Visualizing the Thermal Dehydration Process and Isotope Effect in Single HKUST-1 Metal-Organic...

Area of Science:

• Materials Science
• Chemical Engineering
• Physical Chemistry

Background:

• Quantifying thermal dehydration in metal-organic frameworks (MOFs) at the single-particle level is challenging.
• Understanding MOF reaction dynamics requires precise visualization of water content changes.

Purpose of the Study:

• To quantitatively visualize the thermal dehydration of single metal-organic framework (MOF) particles.
• To investigate the kinetics of thermal dehydration and the influence of isotopes on MOF properties.

Main Methods:

• Utilized in situ dark-field microscopy (DFM) to image single water-containing HKUST-1 (H2O-HKUST-1) MOF particles.
• DFM color intensity was correlated with water content for kinetic parameter quantification.
• Employed molecular dynamics simulations to confirm diffusion coefficient variations.

Main Results:

• DFM successfully mapped water content in single H2O-HKUST-1 particles, enabling quantification of reaction kinetics.
• Thermal dehydration of deutoxide (D2O)-containing HKUST-1 showed higher temperature parameters and activation energy.
• Deuterated MOFs exhibited lower rate constants and diffusion coefficients, demonstrating a significant isotope effect.

Conclusions:

• In situ DFM provides a powerful tool for quantitatively studying single-particle MOF dehydration.
• The observed isotope effect influences thermal dehydration kinetics and diffusion in MOFs.
• These findings offer insights for designing advanced porous materials with tailored properties.