(20a) Catalytic Membranes for Integrated CO2 Capture and Conversion to Value-Added Chemicals

Current CO₂ capture and CO₂ conversion technologies have critical bottlenecks that limit their industrial-scale use, including (i) energy-intensive regeneration stages and (ii) mass transfer limitations due to dilute atmospheric CO₂ concentrations. We are developing a catalytic polymeric membrane technology that addresses these challenges and potentially enables commercially viable CO₂ capture by integrating CO₂ capture and CO₂ conversion to value-added chemicals in a single unit process operated continuously at near ambient temperature and pressure. The innovative enabling technology is a multi-functional polymeric membrane that acts as both the capture medium and conversion medium of CO₂, thereby eliminating the energy intensive step of regeneration. I will discuss our latest progress in the development of this catalytic membrane technology, including materials synthesis and characterization, catalyst testing, membrane testing, in-situ/operando characterization, and membrane reactor demonstrations. I will show that quaternized poly(4-vinylpyridine)-based membranes are particularly promising polymeric membranes for integrating CO₂ capture with CO₂ conversion with epoxides to cyclic carbonates because of their high CO₂ permeance/selectivity, which is related to their unique facilitated CO₂ transport mechanism, and their high catalytic activity for cyclic carbonate synthesis at mild temperatures. I will also demonstrate that the catalytic activity of poly(4-vinylpyridine) can be tuned by quaternization with alkyl bromides of different chain length, and our results suggest that steric hindrance at the pyridinic amine site is a major factor that determines the catalytic activity of the polymer. This concept of intensifying CO₂ capture and CO₂ conversion could revolutionize the way chemicals are produced in the future.