Electrochemical DAC promises up to 50 per cent energy gains

Direct air capture (DAC) – where CO2 is pulled directly from the atmosphere – is viewed as an essential tool to mitigate the worst effects of the climate crisis. Existing methods generally use heat to release chemically captured CO2, but this process requires significant energy, which in turn poses economic challenges for the technology. 

Developed at Rice University, the new DAC technique uses a single-step electrochemical processes to separate CO2 from carbonate and bicarbonate solutions (NaHCO₃/Na₂CO₃). Rice engineers used a modular porous solid electrolyte (PSE) reactor to harvest the CO2, generating an alkaline absorbent (NaOH ). The work is published in Nature Energy.

“Our research findings present an opportunity to make carbon capture more cost-effective and practically viable across a wide range of industries,” said corresponding author Haotian Wang, Associate Professor of Chemical and Biomolecular Engineering at Rice.

“Our reactor can efficiently split carbonate and bicarbonate solutions, producing alkaline absorbent in one chamber and high-purity carbon dioxide in a separate chamber. Our innovative approach optimises electrical inputs to efficiently control ion movement and mass transfer, reducing energy barriers.”