Efficient Direct Air Capture in Industrial Cooling Towers Mediated by Electrochemical CO2 Release.

Direct air capture (DAC) is a promising technology for mitigating global climate change but suffers from low efficiency, small scale, and high cost due to the dilute atmospheric CO2, limited size of air contactors, and heat-driven CO2 release. Here, we propose combining DAC with widely used industrial cooling towers to extract CO2 from the air and using electrolysis to release the captured CO2 at room temperature. We first prepare a buffered absorbent solution consisting of sodium glycinate, glycine, and sodium chloride for effective CO2 capture from the air, solving the incompatibility problem of the cooling towers with conventional absorbents. Next, we employ a three-chamber electrolyzer for efficient release (≥95 %) of the captured CO2 with high purity (≥98 %) by constant current electrolysis at room temperature, bypassing the conventional energy-intensive heating process. The entire DAC system can operate stably for multiple cycles, and the mechanism for consecutive CO2 capture and release is uncovered. This work reveals the great potential of running DAC in industrial cooling towers coupled with electrochemically-driven CO2 release, opening up new avenues for curbing the increasingly severe climate change.