Electrochemical CO2 Reduction Mechanism Exploration: An Integrated Thermodynamic and Kinetic Approach

The electrochemical reduction of CO₂ (eCO₂RR) presents a promising strategy to address sustainable energy challenges by converting CO₂ into value-added chemicals and fuels. This thesis employs density functional theory (DFT) to investigate the reaction mechanisms of eCO₂RR, focusing on enhancing computational mthodologies and understanding catalyst performance. Key challenges such as the low reactivity of CO₂ and competition with the hydrogen evolution reaction (HER) are addressed through a systematic evaluation of molecular catalysts including metal porphyrins and phthalocyanines. The research develops advanced computational approaches to accurately model proton-coupled and decoupled electron transfers, essential for analyzing reaction pathways. The findings highlight bicarbonate as a more favorable intermediate compared to CO₂ under neutral pH conditions. Mechanistic insights into post-CO reactions including the formation of C1, C2, and C2+ products elucidate the role of catalyst design and reaction conditions in achieving multi-carbon product formation form single atom catalysts (SACs). Additionally, the study explores pH-dependent selectivity for formaldehyde and methane which aligns computational results with experimental observations. By providing a comprehensive framework for understanding eCO₂RR pathways, this thesis contributes to the rational design of catalytic systems and optimization of reaction conditions for sustainable energy applications and efficient electrocatalysis.