Study of the oxygen reduction reaction by kinetic Monte Carlo simulations from first-principles

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dc.contributor.authorVanmoerkerke, Willem
dc.contributor.departmentChalmers tekniska högskola / Institutionen för fysiksv
dc.contributor.departmentChalmers University of Technology / Department of Physicsen
dc.contributor.examinerGrönbeck, Henrik
dc.contributor.supervisorGrönbeck, Henrik
dc.contributor.supervisorSvensson, Rasmus
dc.date.accessioned2024-06-17T09:32:56Z
dc.date.available2024-06-17T09:32:56Z
dc.date.issued2024
dc.date.submitted
dc.description.abstractWhile the oxygen reduction reaction is a technologically important and widely studied reaction, the origin of the onset overpotential remains debated. This study aims to elucidate the reaction mechanism and the rate-determining step by kinetic Monte Carlo simulations based on first-principles calculations. It is found that the overpotential is determined by a potential dependent coverage of oxygen species (∗O, ∗OH, ∗H2O) that block O2 adsorption. The coverage is largely determined by adsorbate-adsorbate interactions. Therefore, the origin of these interactions are studied extensively. A model is proposed and implemented in the kinetic Monte Carlo simulations based on d-band shifts of surface atoms and hydrogen bonding interactions. Additionally, attention is given to the effect of an aqueous environment on the adsorbent by employing ab-initio molecular dynamics simulations. The effect of strain, particle size and shape is investigated and particles are optimized using Bayesian optimization. It is shown that particles with sizes between 3 and 6 nm and a large proportion of (111) facets are optimal for the reaction. Furthermore, compressive strains have a positive effect on the activity, while tensile strain reduces activity. Effects of experimentally determined site-specific strain and grain boundaries are explored, which further improve the activity of the catalyst. Subsequently, the limits of the activity is explored by generating kinetic volcano plots from the kinetic Monte Carlo simulations. Following that, the model is generalized to metal alloys, showing how strong interactions between Ag clusters and Pt clusters in AgxPt1–x binary surface alloys can improve catalyst activity. Finally, a framework is presented to simulate linear sweep voltammetries, which can be readily compared with experimental data. Overall, this thesis underscores the significance of interaction effects in accurately describing experimental conditions and introduces a first-principles method for catalyst exploration.
dc.identifier.coursecodeTIFX11
dc.identifier.urihttp://hdl.handle.net/20.500.12380/307878
dc.language.isoeng
dc.setspec.uppsokPhysicsChemistryMaths
dc.subjectOxygen reduction reaction
dc.subjectfuel cell
dc.subjectcomputational catalysis
dc.subjectelectrochemistry
dc.subjectplatinum nanoparticles
dc.subjectadsorbate-adsorbate interactions
dc.subjectkinetic Monte Carlo
dc.subjectDensity-functional Theory
dc.subjectBayesian optimization
dc.titleStudy of the oxygen reduction reaction by kinetic Monte Carlo simulations from first-principles
dc.type.degreeExamensarbete för masterexamensv
dc.type.degreeMaster's Thesisen
dc.type.uppsokH
local.programmeÖvrigt, MSc
local.programmePhysics (MPPHS), MSc
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