Doctoral Defense in Physics - Muhammad Awais

Zoom Link:
https://eu01web.zoom.us/j/67553482472

Doctoral candidate:
Muhammad Awais

Title of thesis:
Exploring Novel Catalysts for Efficient Electroreduction of CO2 to e-Fuels

Opponents:
Dr. Karoliina Honkala, Professor at the Department of Chemistry, University of Jyväskylä, Finland
Dr. Maryam Abdinejad, Assistant Professor at the Department of Energy Conversion and Storage, Technical University of Denmark (DTU), Denmark

Advisor:
Dr. Younes Abghoui, Research Associate Professor, Science Institute, University of Iceland (PhD Supervisor)
Dr. Einar Örn Sveinbjörnsson, Professor, Faculty of Physical Sciences, University of Iceland (Administrative Supervisor)

Other members of the doctoral committee: Dr. Younes Abghoui, Research Associate Professor, Science institute, University of Iceland Dr. Egill Skúlason, Professor, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland Dr. Einar Örn Sveinbjörnsson, Professor, Faculty of Physical Sciences, University of Iceland

Chair of Ceremony:
Dr. Birgir Hrafnkelsson, Professor and Head of the Faculty of Physical Sciences, University of Iceland

Abstract:
Current global energy and environmental challenges can be viewed as the interaction of three connected factors: the use of fossil fuels, carbon dioxide (CO2) emissions, and global warming. The global energy landscape remains largely dependent on fossil fuels, leading to substantial CO2 emissions and disturbing the climatic equilibrium. Nonetheless, one promising strategy for addressing this challenge is to regard CO2 as a resource, thereby converting the challenge into an opportunity for ecological restoration through the use of CO2 for the production of sustainable fuels. This approach turns CO2 into eco-friendly, value-added compounds, promoting greenhouse gas reduction and sustainable energy development. An effective solution to these limitations can possibly be addressed through chemical physics and electrochemistry, particularly through the implementation of the electrochemical CO2 reduction reaction (CO2RR), which converts CO2 into several single and multi-carbon (C1/C2 products) compounds, including carbon monoxide, formic acid, methanol, methane, methanediol, ethylene, ethane, and ethanol. This process can be readily integrated with current renewable energy infrastructure, enabling the coupling of CO2 conversion with sustainable power sources and therefore storing renewable energy as chemical products. However, their practical application remains limited by the low catalytic activity, poor selectivity, and broad product distribution of conventional metal catalysts. In several instances, these catalysts primarily convert CO2 to only CO or formic acid with relative simplicity, whereas the synthesis of more reduced or multi-carbon compounds requires more energy input and often exhibits restricted efficiency. Hence, the electrochemical CO reduction reaction (CORR) may provide essential solutions to tackle the current challenges in the field of CO2RR. Thus, this Ph.D. thesis is dedicated to the exploration of these two research directions to identify more efficient and selective reaction pathways for sustainable carbon transformation via both CO2RR and CORR. To the best of our knowledge, this thesis presents the first systematic computational investigation of transition metal carbonitrides (TMCNs) for electrochemical CO2RR and CORR. A rigorous computational framework using density functional theory (DFT) within the Vienna Ab initio Simulation Package (VASP) was applied to analyze these surfaces for both CO2RR and CORR. This theoretical study examined 33 different catalytic surfaces, eleven TMCNs in (100), (111), and (110) facets, to predict their catalytic activity towards the formation of C1 and C2 products. Moreover, comprehensive computational evaluations were performed to assess the behavior of these different TMCNs in diverse electrochemical environments with pre-adsorbed CO surface coverage. The catalytic performance was investigated using the conventional and the Mars-van Krevelen (MvK) mechanisms and over 2000 reaction pathways to identify the most thermodynamically favorable routes and predict the best TMCN candidate(s) for efficient carbon conversion and management. In the catalytic activity analysis, TMCN(110) was identified as offering the highest activity for both CO2RR and CORR via the MvK mechanism. In conventional pathways, TMCN(111) was found to be the most active for CO2RR, while TMCN(100) was the best for CORR, and TMCN(111) was inactive toward conventional CORR. Overall, this dissertation provides a comprehensive theoretical assessment of TMCNs and offers computationally grounded predictions for their potential use in converting carbon into green fuels, thereby addressing important environmental and sustainable energy concerns.

About the doctoral candidate:
Muhammad Awais is a Ph.D. student with an academic background in Physics. He completed his undergraduate degree in Physics at the University of Education, Lahore, Pakistan, in 2019, with a particular focus on solid-state physics. He subsequently pursued a Master of Philosophy (MPhil) in Physics at Government College University, Lahore, which he completed in 2022, specializing in computational physics. He started his Ph.D. studies in Physics at the University of Iceland in 2023.