Regeneration of direct air CO2 capture liquid via alternating electrocatalysis

The direct air capture (DAC) of carbon dioxide (CO2) can potentially contribute to mitigating past and offsetting hard-to-abate future emissions; however, the regeneration of DAC capture liquids requires high temperatures and thermal energy inputs with emissions that diminish their net environmental benefit. Here, we present a low-temperature electrochemical process to regenerate alkaline capture liquids via alternating electrocatalysis (AE). Colocating oxidation and reduction reactions on a single electrode, cycled between electrolyzer and fuel cell modes, mitigates film formation and losses in the regeneration of alkali hydroxide and hydrogen halide. CO2 can be captured and released with an energy input of 6.4 GJ/tCO2 at 100 mA cm−2 and an emission intensity of ∼11 kg CO2e/tCO2. The direct air capture (DAC) of carbon dioxide (CO2) can potentially contribute to mitigating past and offsetting hard-to-abate future emissions; however, the regeneration of DAC capture liquids requires high temperatures and thermal energy inputs with emissions that diminish their net environmental benefit. Here, we present a low-temperature electrochemical process to regenerate alkaline capture liquids via alternating electrocatalysis (AE). Colocating oxidation and reduction reactions on a single electrode, cycled between electrolyzer and fuel cell modes, mitigates film formation and losses in the regeneration of alkali hydroxide and hydrogen halide. CO2 can be captured and released with an energy input of 6.4 GJ/tCO2 at 100 mA cm−2 and an emission intensity of ∼11 kg CO2e/tCO2.