(278d) Poly(4-vinylpyridine)-Based Catalytic Membranes for Integrated CO2 Capture and Conversion

Current sorbent-based CO₂ capture processes are prohibitively expensive because they require energy intensive regeneration stages to release CO₂ and regenerate the sorbent. Additionally, they produce CO₂ streams that must be compressed and transported to sites for storage, which reduces efficiency. In this talk, I will describe a new catalytic membrane technology that we are developing to address these challenges and potentially enable commercially viable CO₂ capture by integrating CO₂ capture and CO₂ conversion in a single unit process. The membrane acts as both the CO₂ separation and conversion medium, providing an energy- and atom-efficient alternative to sorbent-based CO₂ capture, compression, transport, and storage. In principle, the membrane can couple CO₂ capture with any transformation that involves carbamate or bicarbonate intermediates including, but not limited to, cyclic carbonate synthesis from epoxides, urea synthesis from ammonia, methanol synthesis from hydrogen, and formic acid from water.

We have recently discovered that poly(4-vinylpyridine) (P4VP)-based membranes are promising for demonstrating the potential of nitrogen-functionalized membranes as an integrated CO₂ capture and conversion platform tunable for CO₂ conversion to a variety of products. In this talk, I will demonstrate that P4VP-based membranes are permeable and selective for CO₂ separation from dilute mixed gas streams and are catalytically active for cyclic carbonate synthesis at mild conditions (room temperature and pressure). I will also show that the membrane separation and catalytic performance of P4VP can be tuned and enhanced by quaternization with alkyl bromides to the corresponding quaternary ammonium salt. Finally, I will demonstrate that quaternized P4VP membranes can integrate CO₂ capture from simulated flue gas and convert it to cyclic carbonates in a separate stream at mild conditions. This work establishes the basis for integrating CO₂ capture and CO₂ conversion to valuable products in a continuous process at mild conditions, which represents a transformative shift in carbon capture technology that also mitigates the need for CO₂ compression, transport, and storage.