Enabling Computational Design of ZIFs Using ReaxFF

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Classical force fields are limited in simulating reactive processes in metal-organic frameworks (MOFs).
• Zeolitic imidazolate frameworks (ZIFs) are increasingly studied for glass formation, defect engineering, and chemical stability.
• There is a need for advanced computational methods for efficient ZIF material screening.

Purpose of the Study:

• To present simulations of three ZIF compounds using the ReaxFF reactive force field.
• To evaluate ReaxFF's capability in reproducing structural, thermal, and morphological properties of ZIF-based glasses.
• To predict the melting behavior and stability of different ZIFs.

Main Methods:

• Simulations of the melt-quench process for ZIF-4 using ReaxFF.
• ReaxFF simulations of ZIF-62 melting.
• ReaxFF simulations of ZIF-77 to predict melting point and stability.

Main Results:

• ReaxFF accurately reproduced the atomic structure, density, thermal properties, and pore morphology of ZIF-4 glass.
• ReaxFF predicted a lower melting point for ZIF-62 due to electronic and steric effects.
• ReaxFF simulations indicated ZIF-77 has a lower melting point but poor chemical stability, making it unsuitable for glass formation.

Conclusions:

• ReaxFF is a capable tool for simulating reactive processes in ZIFs, including glass formation and melting.
• The computational efficiency and transferability of ReaxFF facilitate the design of ZIF materials.
• ReaxFF enables the consideration of disorder and defects in ZIF material design.