(2ka) Unraveling the Chemistry on Metal/Metal Oxide Catalysts with Automated Mechanism Generation and Multiscale Modeling

Heterogeneously catalyzed processes, like aviation fuel synthesis or plastic waste upcycling, are crucial to establish a circular economy and to mitigate emissions. Advancing these processes requires an understanding of the detailed processes on the atomic scale. Microkinetics provide access to the potential energy surface, allowing us to tailor catalysts and improve reactor operation. Designing reactors using ab-initio information demands multiscale modeling approaches to bridge the material and pressure gap. Many of these processes proceed over complex active site motifs on metal/metal oxide surfaces or their interfaces. Additionally, the conversion/production of large molecules requires the construction of intricate microkinetics with an overwhelming number of intermediates and elementary steps. Overcoming this complexity necessitates a rigorous automated exploration of the chemical reaction space. Mechanistic insights are then achieved in combination with catalytic experiments. My research group aims to unravel the conversion processes over complex catalysts by integrating (i) ab-initio-based automated mechanism generation with (ii) multiscale modeling frameworks and (iii) catalytic experiments. Leveraging my diverse scientific background in chemical engineering, I can combine all these research topics in a single group. This combination allows me to break down the frontiers that separate atomic and reactor scale to propel scientific advancements with innovative solutions.

Research Experience

PhD research (Advisor: Thomas Turek, Clausthal University of Technology, Germany)

My research focused on the transient CO₂ methanation in Power-to-Gas scenarios, which exhibits complex dynamics, as seen by detailed macroscopic reactor modeling [1]. Employing a combination of experiments and theoretical methods, I developed suitable kinetic approaches to describe the transient reactor operation. I synthesized multiple Ni catalysts with a range of techniques and characterized them through physical and chemical methods [2,3]. These catalysts were utilized in dynamic kinetic experiments in plug flow and Berty-type reactors. To accurately describe the transient phenomena on the catalyst surface, it is necessary to use microkinetic models. Therefore, I joined the group of Prof. Franklin Goldsmith (Brown University) for a research stay, to gain expertise in quantum chemistry, automated mechanism generation with the Reaction Mechanism Generator (RMG), and microkinetic modeling of multifaceted catalysts [3]. By combining automated mechanism generation with uncertainty quantification and kinetic experiments, my research provided new insights into the transient CO₂ methanation [4,5].

Short postdoctoral research stay (Advisor: Olaf Deutschmann, Karlsruhe Institute of Technology, Germany)

After the PhD, I did a 2-month postdoctoral visit in the group of Olaf Deutschmann at KIT to apply the methods I developed for the automated mechanism construction and microkinetic modeling to shed new insights into the intricate oxidation of exhaust gas emissions over Pt catalysts [6].

Postdoctoral research (Advisor: C. Franklin Goldsmith, Brown University)

For my postdoctoral research, I received the Feodor Lynen Research Fellowship from the Alexander von Humboldt Foundation, the most prestigious postdoctoral award available in Germany. At Brown, I continued to enhance the capabilities of RMG to address the complexity of reactions on surfaces (e.g., multidentate functionalities, improved thermophysical/kinetic databases, and estimation routines) and combined it with sophisticated correlated uncertainty quantification methods [7]. These updated features are necessary to automate the mechanism generation for the Co-catalyzed Fischer-Tropsch synthesis, which is my current project. Obstacles for the investigation of this reaction are the high coverage of adsorbates on the complex active site motif, which I’m addressing with coverage-dependent thermochemistry and multifaceted catalysts models. Additionally, I expanded my knowledge in quantum chemistry, devising a new method that combines experimental data with DFT energies to calculate more accurate thermophysical values of adsorbates [8].

Teaching Interests

I am a chemical engineer by training with a strong teaching background. During my graduate studies, I had the opportunity to be a teaching assistant and guest lecturer in courses on the fundamentals of chemical engineering and mathematical reactor design. These courses involved hands-on coding exercises and guiding students in their projects. Additionally, I mentored and supervised 3 bachelor and 3 master students, where I gained skills to support academic endeavors on experimental and theoretical projects effectively. In my postdoc at Brown, I broadened my teaching repertoire according to my research trajectory and was a guest lecturer in the course “Atomistic Reaction Engineering” of Prof. Andrew Peterson, highlighting my ability to teach chemical engineering across various lengths and time scales. I’m comfortable teaching multiple topics, from reactor design over kinetics and thermodynamics to computational chemistry. I aspire to establish new courses at the graduate level focused on multiscale modeling. My teaching philosophy is rooted in fostering an inclusive environment that encourages critical thinking, active participation, and hands-on application so that the students have the knowledge and skills to excel in their chosen paths.

Selected Publications (*=corresponding author(s)); 19 publications, 11 first author

[1] B. Kreitz*, G. D. Wehinger, and T. Turek. “Dynamic simulation of the CO₂ methanation in a micro-structured fixed-bed reactor”. Chem. Eng. Sci., 195 2019, 541–552

[2] B. Kreitz*, A. Martínez Arias, J. Martin, A. P. Weber, and T. Turek. “Spray-Dried Ni Catalysts with Tailored Properties for CO₂ Methanation”. Catalysts, 10 (12), 2020, 1410

[3] B. Kreitz*, G. D. Wehinger, C. F. Goldsmith, and T. Turek. “Microkinetic Modeling of the CO₂ Desorption from Supported Multifaceted Ni Catalysts”. J. Phys. Chem. C, 125 (5), 2021, 2984–3000

[4] B. Kreitz*, K. Sargsyan, K. Blöndal, E. J. Mazeau, R. H. West, G. D. Wehinger, T. Turek, and C. F. Goldsmith*. “Quantifying the Impact of Parametric Uncertainty on Automatic Mechanism Generation for CO₂ Hydrogenation on Ni(111)”. JACS Au, 1 (10), 2021, 1656–1673

[5] B. Kreitz, G. D. Wehinger, C. F. Goldsmith, and T. Turek*. “Microkinetic modeling of the transient CO₂ methanation with DFT-based uncertainties in a Berty reactor”. ChemCatChem 2022, e202200570

[6] B. Kreitz*, P. Lott, K. Blöndal, J. Bae, S. Angeli, Z. W. Ulissi, F. Studt, C. F. Goldsmith, and O. Deutschmann*. “Detailed microkinetics for the oxidation of exhaust gas emissions through automated mechanism generation”. ACS Catal., 12 (18), 2022, 11137–11151

[7] B. Kreitz*, P. Lott, A. J. Medford, F. Studt, O. Deutschmann, and C. F. Goldsmith*. “Automated Generation of Microkinetics for Heterogeneously Catalyzed Reactions Considering Correlated Uncertainties”. (under revision at Angew. Chem. Int. Ed. , DOI: 10.26434/chemrxiv-2023-hnb4l)

[8] B. Kreitz*, K. Abeywardane, and C. F. Goldsmith*. “Linking Experimental and Ab-initio Thermochemistry of Adsorbates with a Generalized Thermochemical Hierarchy”. J. Chem. Theory Comput. 2023, DOI: 10.1021/acs.jctc.3c00112