Continuous Light-Driven Pure CO2 Production by Regenerative Non-Aqueous Amine–Photoacid Cycling

Photochemical CO2 separation offers a low-temperature alternative to conventional thermal CO2 separation, replacing fuel-derived heat with light as the energy input. Although prior photoacid and photobase systems have shown promising light-driven CO2 capture–release behavior, continuous pure-CO2 generation from dilute feeds remains insufficiently developed. Here, we demonstrate light-driven pure-CO2 production from a 15% CO2 feed, reaching 3.2 sccm from 1.2 mL min−1 of circulating sorbent solution in a single lab-scale reactor, equivalent to 4.6 L day−1. In the dimethyl sulfoxide amine–photoacid platform, acidity matching allows each photoacid molecule to undergo repeated excited-state proton transfer, coupling carbamic acidforming CO2 capture to efficient release. The evolved CO2 forms self-generated bubbles without external sweep gas in the reduced-pressure continuous flow photoreactor developed in this work. Techno-economic analysis projects a minimum separation cost of $31.7 tCO2 −1 from 15% CO2 source. These results establish a practical foundation for scalable light-driven carbon capture.