CO₂ Capture from Dilute Sources

Capture and conversion of CO₂ from anthropogenic emission is becoming an increasingly important social responsibility as the concentration of atmospheric CO₂ continues to rise above record high levels. CO₂ from the atmosphere, oceanwater and point sources are considered as the major feedstock for subsequent capture and conversion processes.

Xiang's research team is working on electrochemical approaches for CO₂ capture from dilute sources, e.g., air and oceanwater. The team is developing electrochemical processes, in which CO₂ can be captured from dilute sources and released in high concentration by shifting the pH of a working fluid between acidic and alkaline pH, using renewable electrons as the only energy input. The team will develop new materials and device architectures that allow extremely high-rate generation of pH swings needed for the release of concentrated CO₂ and the regeneration of the CO₂ absorbent at room temperature. The capture system will also use catalytic materials that enhance the inter-conversion between CO₂ and bicarbonate to facilitate the capture and release processes at the liquid-gas interfaces. Dilute CO2 capture via electrochemical approaches has the potential to scale CO₂ capture to the multi-Gt/year level with a cost of < $100/ton in the coming decades. An early stage company, Captura Crop., was founded in 2021 to commercialize and scale up technologies and systems developed at Caltech for extracting CO₂ from oceanwater at scale to meet the rapidly growing demand in the carbon credit market.