Conducting Covalent Organic Frameworks with Potential for Energy Storage & Metal-Cluster Embedded COFs for CO2 Reduction Reaction

Abstract

Covalent Organic Frameworks (COFs) are an emerging class of crystalline porous polymers constructed via reticular chemistry, offering a modular platform with tunable porosity, high surface area, and excellent thermal and chemical stability. This thesis presents a comprehensive investigation into the strategic design and synthesis of functional COF architectures for advanced energy storage and sustainable electrocatalysis. The work is divided into two parts, each addressing a critical scientific challenge by leveraging the intrinsic structural advantages of COFs. Part A focuses on the development of conductive COFs for energy storage applications. Through two systematic studies, innovative design strategies are introduced to overcome limitations in charge transport. Chapter 2 describes a post-synthetic modification approach wherein quasi-3D architectures are achieved by integrating polypyrrole-based conjugated bridges, significantly enhancing electronic conductivity for supercapacitor applications. Chapter 3 builds on this approach by incorporating both electronic and ionic conductive motifs into a single COF, enabling mixed conduction and establishing a new class of multifunctional electrode materials for next-generation energy technologies. Part B explores the design of metal cluster-embedded COFs (M-COFs) as efficient heterogeneous electrocatalysts for CO₂ reduction. Chapter 4 investigates the influence of electrolyte composition on catalytic performance, highlighting the critical role of anions in modulating the activity and selectivity of M-COFs toward CO₂ reduction. Chapter 5 examines structure-activity relationships by embedding pentanuclear Fe, Co, and Zn clusters into COF skeleton and systematically analyzing their electronic effects on catalytic behavior. This integrated approach elucidates fundamental design principles for M-COF catalysts, emphasizing the importance of active site tuning within robust porous scaffolds. Overall, the findings of this thesis provide valuable insights into the design of COF-based functional materials and open new avenues for their application in energy storage and electrocatalysis through strategic modulation of structure-property relationships.