Conjugated Microporous Polymers for Catalytic CO₂ Conversion

Abstract

Rising carbon dioxide (CO2) levels in the atmosphere are recognized as a threat to atmospheric stability and life. Although this greenhouse gas is being produced on a large scale, there are solutions to reduction and indeed utilization of the gas. Many of these solutions involve costly or unstable technologies, such as air‐sensitive metal–organic frameworks (MOFs) for CO2 capture or “non‐green” systems such as amine scrubbing. Conjugated microporous polymers (CMPs) represent a simpler, cheaper, and greener solution to CO2 capture and utilization. They are often easy to synthesize at scale (a one pot reaction in many cases), chemically and thermally stable (especially in comparison with their MOF and covalent organic framework (COF) counterparts, owing to their amorphous nature), and, as a result, cheap to manufacture. Furthermore, their large surface areas, tunable porous frameworks and chemical structures mean they are reported as highly efficient CO2 capture motifs. In addition, they provide a dual pathway to utilize captured CO2 via chemical conversion or electrochemical reduction into industrially valuable products. Recent studies show that all these attractive properties can be realized in metal‐free CMPs, presenting a truly green option. The promising results in these two fields of CMP applications are reviewed and explored here.

Biopolymeric Nanocomposites for CO2 Capture

“…Carbon dioxide separation from dinitrogen and methane is made possible by using biopolymeric membranes with specific molecular porosity. Microporous particles may also be incorporated into the membranes by functionalization and crosslinking reactions to create nano- (0.7–2 nm) and ultrananopores (<0.7 nm) to improve CO 2 permeability and selectivity [ 45 ].…”

Tetrabenzonaphthalene and Redox-Active Anthraquinone-Linked Conjugated Microporous Polymers as Organic Electrodes for Enhanced Energy Storage Efficiency

“…They are distinguished by their high porosity, lightweight structure, and robust covalent bonds. − As a subset of covalently bonded organic porous materials, CMPs are amorphous and facilitate the conjugated assembly of building blocks within three-dimensional (3D) networks. − CMPs possess distinctive structural characteristics not found in other porous materials, which typically lack π-conjugation, or in conventional conjugated polymers, which are not porous. − CMPs leverage π-conjugated systems, allowing for deliberate modifications to their porous structures, thus enhancing both the framework and its properties. − CMPs can be synthesized through various chemical methods, including the Yamamoto reaction, Friedel–Crafts arylation, cyclotrimerization, Suzuki reaction, Sonogashira–Hagihara reaction, and Schiff base reaction, all of which contribute to the formation of these unique CMPs. − The design of CMPs allows for versatile applications. Primarily, they are utilized for their energy storage, photocatalytic H 2 production, chemical sensing, and biological applications. ,,,− However, significant challenges hinder the practical application of CMPs in electrochemical energy storage. The naturally low electrical conductivity of CMPs restricts charge transport within the frameworks, thereby limiting their electrochemical performance.…”