Doctoral Defens in Chemical Engineering - André Philipp Wark

Doctoral candidate:
André Philipp Wark

Title of thesis:
Elucidation of Electrocatalytic Oxidation Reactions on Abundant Materials - Combination of Theory and Experiment

Opponents:
Dr. Jakob Kibsgaard, Professor at the Department of Physics at the Technical University of Denmark (DTU), Denmark, dr. Núria López, Professor at the Institute of Chemical Research of Catalonia (ICIQ), Spain.

Advisor:
Dr. Egill Skúlason, Professor at the Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland.

Also in the doctoral committee:
Dr. Andrew J. Medford, Assistant Professor at the School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, United States of America, dr. Hannes Jónsson, Professor at the Faculty of Physical Sciences, University of Iceland.

Chair of Ceremony:
Dr. Rúnar Unnþórsson, Professor and Head of Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, The University of Iceland.

Abstract:
The anthropogenic climate crisis, driven by excessive greenhouse gas emissions from a fossil-fuel-based economy, poses a major global challenge. This crisis necessitates a transition to a sustainable society, not only for environmental and societal reasons but also due to its economic implications. Affordable and abundant resources are essential for developing devices like fuel cells to reduce greenhouse gas emissions. One key area of research involves the Oxygen Evolution Reaction (OER) at the oxidative anode. One project of this thesis examines Highly-Oriented Pyrolytic Graphite (HOPG) as an anode substrate for manganese oxide nanosheets (MnO2NS). Electrochemical measurements indicate enhanced OER activity for HOPG/MnO2NS, attributed to the interface between the substrates and nanosheets, as shown by noise electrochemical scanning tunnelling microscopy (n-EC-STM). Density Functional Theory (DFT) calculations identify the active centers further as the terminal oxygen moieties at the MnO2NS edges, proposing a plausible OER mechanism that aligns with experimental results. Expanding our previous study, research on carbonized iron phthalocyanines (CFePc) reveals superior OER performance compared to HOPG/MnO2NS. When combined with MnO2NS, CFePc shows improved OER activity, especially at low overpotentials. DFT calculations suggest that the low-potential activity originates from the interface between the substrate and MnO2NS, while CFePc dominates at high overpotentials. Finally, the study explores the competition between the OER and Nitrogen Oxidation Reaction (NOR) on a TiO2(110) electrode using Grand Canonical DFT calculations, considering both explicit and implicit solvation. The results indicate a close competition between the two reactions, determined by their kinetics and the solid-liquid interface composition.

About the candidate:
André Philipp Wark earned his BSc and MSc degrees in Chemistry from the University of Bremen, Germany, in 2019. His Master's research focused on the theoretical investigation of platinum nanoparticles functionalized with amino acids for enantiopure hydrogenation reactions. He then joined the research group of Prof. Egill Skúlason at the University of Iceland's Faculty of Industrial Engineering, Mechanical Engineering, and Computer Science as a PhD candidate. André's doctoral research centered on elucidating electrochemical oxidation reactions using quantum chemical methods. He collaborated with experimental partners at the Osaka Research Institute of Industrial Science and Technology in Japan and the Technical University of Munich in Germany. After completing his PhD, André will pursue postdoctoral research at the Technical University of Denmark in Copenhagen.