Bioinspired Photocatalytic CO₂ Reduction Exploiting CO₂ Direct Air Capture (DAC) and III-V Semiconductors

Photocatalytic CO₂ reduction (CO₂R) promises scalable conversion of atmospheric CO₂ to chemicals or fuels. Currently, most photocatalytic CO₂R systems require concentrated and gaseous CO₂ as feedstock. This process requires extra energy and carbon footprint, especially when separating 410 ppm CO₂ directly from the air. We demonstrate a design that enables photocatalytic CO₂R and local CO₂ production simultaneously using photocatalytic panels consist of III-V semiconductors and reversible quinone redox mediators. Our design, which draws inspiration from photosynthesis, consists of enriching CO₂ in a (bi)carbonate solution, spatially separating surface reaction sites and driving local pH swing to release CO₂ locally, and reducing CO₂ into CO₂R products eventually. We show that in the presence of quinone redox couples in a bicarbonate solution, CO is produced in a 1-atm Ar environment where the only source of CO₂ is the (bi)carbonate anions. Finally, we construct a COMSOL Multiphysics model that accounts for all the reaction kinetics to simulate the photocatalytic reaction during operation