Date/Time
06.06.2024
2:00 pm – 3:00 pm
Location
Lecture Hall 55.02
Pfaffenwaldring 55
70569 Stuttgart
We are very happy to welcome within the CRC 1333 Colloquium Series:
Thursday, June 06, 2024, 2:00-3:00 pm
Ruhr-University Bochum, Computational Materials Chemistry
Topic: Molecular Dynamics Simulations of MOF Nanocrystallites: The Direct Observation of an Adsorption Induced Phase Transformation
Abstract:
Metal-organic frameworks (MOFs) have become an intensively investigated novel class of porous materials due to their tunability, combined with crystallinity. Kitagawa coined the term “soft porous crystals”, since certain MOFs can structurally respond to external stimuli. For example, their ability to undergo phase transformations upon adsorption of guest molecules with large changes in the accessible pore volume are of high interest in various fields of application. Theoretical simulations are a key tool to understand such processes on a molecular level, however, adsorption phenomena are usually investigated within the approximation of periodic boundary conditions (PBC) and using Grand Canonical methods. This simulation setup excludes, however, the interface between the MOF and the gas reservoir and ignores any transport effects, which basically prevents the investigation of kinetics.
Some time ago our group started to develop and apply a methodology to simulate explicit MOF nanocrystallites (NCs) beyond PBC, with the far aim to understand experimentally observed size effects [1,2,3].
In my presentation, I will briefly sketch the methodology using specifically parameterized force fields, which are accurate and yet efficient. The difficulties and advantages of simulating nanocrystallites, with up to millions of atoms, will be discussed. Recent results on the pore opening of DUT-8(Zn) nanocrystallites (about 10 nm size) in carbon dioxide by unbiased molecular dynamics simulations reveal that phase transformations can proceed within a few nanoseconds. The simulations allow an unprecedented view on the actual process, including both the mechanics of the phase transformation of the MOF and the diffusive transport of the guest molecules from the reservoir into the MOF.
[1] J. Keupp, R. Schmid, Adv. Theory Simul. 2019, 2, 1900117.
[2] L. Schaper, J. Keupp, R. Schmid, Front. Chem. 2021, 9, 757680.
[3] L. Schaper, R. Schmid, Commun. Chem. 2023, 6, 233.
The research of Prof. Schmid group is focused on the development and application of theoretical methods for the simulation of complex systems in materials chemistry on an atomistic level. All projects have in common that they try to develop atomistic models which are able to bridge the length- and time-scales and thus to overcome the intrinsic problem in the simulation of materials systems.
The CRC 1333 cordially invites all who are interested to the lecture.