Perylene- and Naphthalene-based Porous Polyimide Networks for CO₂ Capture and Conversion

Abstract

Porous polyimides (pPIs) represent a fascinating class of porous organic polymers (POPs) known for their exceptional thermal and chemical stabilities, as well as high surface areas, and energy storage capabilities. pPIs are synthesised through simple polycondensation reactions utilising a diverse array of linkers (dianhydrides) and cores (amines) to form highly crosslinked networks. The surface areas and pore sizes of pPIs are optimised using the Bristol-X’an-Jiatong (BXJ) approach. This thesis demonstrates how the BXJ approach can be used to optimise the porous network properties to target and tune their ability to capture CO₂. Once optimised, these porous organic frameworks were utilised, for the first time, as metal-free electrocatalysts for the conversion of CO₂. The excellent faradaic efficiencies (FEs) for the electrochemical conversion of CO₂ to formate (91%) and methanol (95%) present exciting opportunities for the generation of useful fuels and feedstocks from CO₂. In addition, the ability to directly address and select the conversion products through tuning of the porous materials’ properties highlights the potential of this work, and more generally for a wide range of organic frameworks, as future metal-free CO₂ reduction catalysts. Additionally, pPIs were utilised as a metal-free heterogeneous catalyst for the first time, in synthesising cyclic carbonates from CO₂ and epoxides. pPIs exhibit excellent reusable heterogeneous catalytic activities under very mild and sustainable conditions (solvent- and co-catalyst free) with 99.9% conversion to cyclic carbonate. A wide substrate scope of pPIs for cyclic carbonate synthesis was investigated, making them promising candidates for green and sustainable industrial synthesis.

Date of Award	23 Jan 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Charl F J Faul (Supervisor)