Midway evaluation in Physics - Muhammad Awais

Title of thesis: Exploring new catalyst for efficient electroreduction of CO₂ to fuels

Student: Muhammad Awais

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

Abstract

The Earth's ecology is under unprecedented stress, and equilibrium seems to be compromised. A recent increase in temperature, glacial melting, and noticeable swings in global climate have been observed, with the main root cause of these criticalities linked to the substantial and unregulated discharge of greenhouse gases (GHGs). However, on the other side, a rising population, industrial growth, and technical breakthroughs are mainly centered on traditional energy supplies such as fossil fuel combustion, which results in the facile emission of GHGs such as carbon dioxide (CO2). The generation of renewable energy and the mitigation of CO2 emissions are essential in the contemporary period to safeguard the planet from global warming and climate deterioration. The optimal strategy may include converting released CO2 into sustainable energy sources instead of sequestering it. This approach might facilitate the closure of the carbon loop, aiding in achieving the net-zero emissions goals and the acquisition of clean and green energy. The transformation of CO₂ into useful products has emerged as a prominent research focus in recent years, using various methodologies such as thermochemical, biochemical, photochemical, and electrochemical processes. Previous research clearly demonstrates that turning waste CO₂ into sustainable chemical feedstocks has two advantages: meeting rising energy needs and reducing carbon emissions. Of all the proposed strategies, electrochemical methods are notably advantageous owing to their easy compatibility with renewable energy technologies. In this context, the primary aim of the present work is to identify and evaluate suitable catalytic surfaces for the electrochemical CO2 reduction reaction (CO2RR) and CO reduction reaction (CORR). To achieve this goal, a quantum mechanical simulation based on density functional theory (DFT) was employed to systematically assess the catalytic activity of numerous metal-based catalytic surfaces for CO2/CORR. During the initial examination, CO adsorption was observed to be more exergonic and thermodynamically favorable than CO2, paving the way for facile CORR. By considering the different electrochemical environment in the presence of coverage species, CO2/CORR was reevaluated and reported different reaction pathways and products. These reduction reactions facilitate the single- and multi- carbon products such as formic acid, methanol, methane, ethylene and ethanol. In a nutshell, due to the comprehensive evaluation of catalytic reactivity involving CO2/CO adsorption, activation, and reduction across numerous possible reaction pathways, together with a detailed investigation of proton adsorption, this study provides fruitful theoretical insights about selected surfaces. It also provides a complete roadmap about catalytic activity, selectivity and stability under the different electrochemical conditions. Furthermore, this theoretical study offers robust predictions for future experimental verification and facilitates the development of a proficient electrocatalytic system for cleaner and more sustainable energy production by enabling the closing of the carbon loop.