Reticular Design of Porous Nitrogen-rich Organic Nanostructures for Energy Storage and Conversion

Karak, Shayan (2025) Reticular Design of Porous Nitrogen-rich Organic Nanostructures for Energy Storage and Conversion. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Shayan Karak (18IP017)) 18IP017.pdf - Submitted Version Restricted to Repository staff only Download (32MB)

Abstract

The ongoing global energy crisis demands materials that can store and convert energy efficiently while withstanding real-world operating conditions. Porous organic materials, particularly covalent organic frameworks (COFs) and porous organic polymers (POPs), have emerged as promising candidates due to their tunable architecture, low density, and structural diversity. Reticular chemistry provides a powerful approach to precisely program functionality, stability, and porosity into these frameworks. This thesis adopts a function-first reticular design perspective, bridging crystalline and amorphous systems, to deliver materials with targeted performance in electrocatalysis, batteries, CO₂ reduction, and energetic applications. Chapter I introduces the overarching perspective, positioning functionality, chemical stability, and application relevance above structural perfection. It critically examines the literature on COFs and POPs for energy applications, highlighting overlooked opportunities in amorphous frameworks and heteroatom-rich systems as programmable platforms for real-world devices. Chapter II presents the design and synthesis of benzimidazole-linked POPs, demonstrating their stability and nitrogen-rich backbone as key contributors to excellent electrocatalytic hydrogen and oxygen evolution performance. Detailed analysis reveals how irreversible linkages and conjugated heterocycles enable high activity under harsh alkaline conditions. Chapter III explores dibenzamide-linked POPs, termed porous polybenzamides, as advanced organic electrode materials for lithium-ion batteries (LIBs). The linkage itself demonstrates redox behavior, which is capable of reversibly storing Li⁺ during the cycling process. The work correlates redox-active sites and microporosity with charge storage capacity, showing that careful linker choice ensures prolonged cycling stability and high reversible capacity. Chapter IV focuses on the construction of crystalline COF nanotubes from non-planar linkers, providing one-dimensional (1D) channels with enhanced transport properties. The unique topology and ordered pore alignment enable efficient electrolyte infiltration, improving electrochemical performance in energy storage devices. Chapter V shifts to an emergent woven Cu-TNPG superstructure, where molecular weaving is achieved through coordination chemistry, hydrogen bonding, and electrostatic interactions. This framework serves as a platform for visible-light-driven CO₂ photoreduction, demonstrating the potential of synergistic metal–organic and non-covalent design in catalysis. Chapter VI addresses the challenge of balancing mechanical stability, thermal robustness, and energetic performance in nitrogen-rich energetic materials. Alkaline metal coordination with TNPG is used to tune mechanical hardness and stability without sacrificing detonation properties, offering a rare combination of safety and performance.

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