Potassium -alanine - A promising agent for reducing carbon capture cost via electrochemically mediated amine regeneration

Electrochemically mediated amine regeneration (EMAR) for CO2 capture is a promising substitute for traditional organic amine-based CO2 capture by replacing the thermal process with electricity. To avoid problems such as oxidative degradation, toxicity, volatilization, and precipitation of organic amine absorbent, potassium beta-alanine was suggested as an absorbent using EMAR process for the first time in this study. The CO2 absorption performance under different copper loading and chemical reactions were studied, and cyclic voltammetry, electro-chemical impedance spectroscopy, chronocoulometry and the Taffel extrapolation method were used to study the electrochemical characterization. Compared to the benchmark monoethanolamine (MEA) system, a smaller potential difference between oxidation and reduction peak was acquired in the potassium beta-alanine system, of which the energy consumption was only 44.1% of the MEA system at the current of 100 A/m2. The cathode Faraday efficiency in the potassium beta-alanine system was 101.9% higher than that in the MEA system at the current density of 25 A/m2. Furthermore, the result of scanning electron microscope of the electrode surface after desorption showed that potassium beta-alanine absorbent improved the inhomogeneity of the electrode surface and was in favor of uniform current distribution. Overall, potassium beta-alanine can be used as a more environmentally friendly absorbent in the EMAR system and has great potential to further reduce the actual energy consumption and improve the Faraday efficiency and cycling performance.