Electrochemical hydrogen production using captured CO₂ in alkaline solution

In this work, a less toxic and corrosive captured CO₂ in alkaline solution (KLC) supplied by the LowCarbon Co. was used as an electrolyte. A flow cell equipped with 25 cm² nickel-based electrodes and a separator membrane was employed to produce H₂ gas. A gas chromatography analysis of the exit gases showed that 99.75 % of H₂ was produced at the cathode, while O₂ was produced at the anode. However, CO₂ gas was not detected in any of the exit gases. Performance evaluation of the cells revealed three processes through electrochemical impedance spectroscopy. A comparison of performance between cells operated using KLC and 10 wt% NaOH solutions as electrolytes revealed a significant overpotential in the KLC solution compared with NaOH, which is attributed mainly to the low electrical conductivity of the component ions as well as the nature of the anions.