Layered double hydroxides (LDHs) are a class of solid adsorbents characterized by a bimetallic hydroxide layer intercalated with water and anions. Calcium-based LDHs have shown recent promise to compete with other solid adsorbents for CO
2 capture, with a reported capture capacity of 4.3 ± 0.5 mmol/g at 30 °C and 40% relative humidity. In particular, LDH CO
2 capture capacity improves in the presence of water, while for adsorbents such as MOFs and zeolites H
2O and CO
2 typically compete for adsorption sites. Although calcium-based LDHs show promise for concentrated CO
2 sources of high humidity, such as flue gas (5-15 vol. % H
2O), the specific mechanism of adsorption is incomplete including the role of H
2O molecules. Moreover, the application of non-conventional regeneration approaches for Ca-based LDHs remains largely unexplored. In this work, the mechanism of CO
2 adsorption by chloride-containing Ca-based LDHs with different trivalent cations will be discussed together with desorption behavior caused by exposure to low-temperature non-equilibrium plasma. Adsorption and desorption behavior have been elucidated using
in operando diffuse reflectance infrared Fourier transform spectroscopy coupled with a residual gas analyzer, with complementary material characterization via X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Initial experiments have been performed on the impact of humidity on CO
2 adsorption, with
in operando thermal desorption being carried out up to ~650 °C (limit of
in operando conditions). These experiments show the unique role of interlayer H
2O in the LDH for conversion of CO
2 to carbonate species during adsorption and that CO
2 desorption commences at a lower temperature than currently reported in the literature. Moreover, CO
2 desorption experiments conducted using low-temperature non-equilibrium plasma reveal that desorption is aided by the application of the plasma, and some CO
2 is found to desorb even at room temperature.
