| dc.contributor.advisor | Wodtke, Alec M. Prof. Dr. | |
| dc.contributor.author | Borodin, Dmitriy | |
| dc.date.accessioned | 2022-01-13T13:52:56Z | |
| dc.date.available | 2022-12-12T00:50:09Z | |
| dc.date.issued | 2022-01-13 | |
| dc.identifier.uri | http://hdl.handle.net/21.11130/00-1735-0000-0008-59EB-C | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-9032 | |
| dc.language.iso | eng | de |
| dc.publisher | Niedersächsische Staats- und Universitätsbibliothek Göttingen | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 540 | de |
| dc.title | Probing Molecule-Surface Interactions through Thermal Desorption Rates | de |
| dc.type | cumulativeThesis | de |
| dc.contributor.referee | Wodtke, Alec M. Prof. Dr. | |
| dc.date.examination | 2021-12-14 | |
| dc.description.abstracteng | The accurate description of chemical reaction rates at surfaces is essential for the understanding
of heterogeneous catalysis. As industrial catalysts are in general complex,
fundamental understanding on how they work requires input from theory, typically
using density functional and transition state theory. These methods are the state of-the-art tools to acquire elementary rate constants, which serve as building blocks
of kinetic mechanisms. The resulting mechanisms allow us to evaluate the catalyst's
activity and selectivity for a particular chemical transformation. Unfortunately, the
established theoretical methods for prediction of rate constants lack validation from
detailed experiments of which there are few. In the present cumulative thesis, experimental
techniques and analysis procedures were developed, allowing to test the
established methods for rate constant prediction based on accurate measurements of
thermal desorption rates. Kinetic experiments on single crystal surfaces were made possible
by the velocity resolved kinetics approach under ultra-high vacuum conditions.
I exploited the far-transition-state concept, based on which the molecule's binding
energy to and entropy at the surface are directly obtained from thermal desorption
rate constants. The binding energies are valuable benchmarks to evaluate the accuracy
of the electronic-structure theory. The entropies serve as a critical test to models
employed for the description of adsorbate's partition function, essential for the description
of thermodynamic and kinetic properties of surface chemistry. In addition,
adsorbate entropies serve as a valuable probe for molecule-surface interactions. In
this work I present experimental and kinetic modeling studies on four molecule-surface
systems H2/Pt(111,332), NO/Pd(111,332), CO/Au(111,332) and NH3/Pt(111,332)
which allowed me to make the following conclusions: 1) Thermal desorption rates are
a sensitive probe for molecule-surface interactions and can provide information beyond
binding energies only. Detailed modeling of adsorbate entropy allows the quantiffcation
of diffusion barriers and vibrational relaxation times based on thermal desorption rates.
2) Established models for adsorbate partition functions lack accuracy as they ignore
quantum effects and rely on the assumption of decoupled degrees of freedom. Strategies
to account for these effects are presented. 3) The desorption rate from surfaces
with atomic steps can be dominated by entropic effects, despite the molecule's higher
energetic stabilization at steps. These effects will likely be important for surface reactions
as well. 4) Elementary parameters obtained from experiments at single crystal
surfaces and models developed to explain these experiments have enough transferability
to understand aspects of heterogeneous catalysis at industrially relevant conditions
and at real catalytic materials. This work provides a perspective that reaction kinetics
at surfaces can be a more exact science. | de |
| dc.contributor.coReferee | Schwarzer, Dirk Prof. Dr. | |
| dc.subject.eng | heterogeneous catalysis | de |
| dc.subject.eng | transition state theory | de |
| dc.subject.eng | velocity resolved kinetics | de |
| dc.subject.eng | statistical mechanics | de |
| dc.subject.eng | surface science | de |
| dc.subject.eng | molecular beams | de |
| dc.subject.eng | ion imaging | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-21.11130/00-1735-0000-0008-59EB-C-2 | |
| dc.affiliation.institute | Fakultät für Chemie | de |
| dc.subject.gokfull | Chemie (PPN62138352X) | de |
| dc.description.embargoed | 2022-12-12 | |
| dc.identifier.ppn | 1786028212 | |