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.