Encapsulation of Phase-Changing Eutectic Salts in Magnesium Oxide Fibers for High-Temperature Carbon Dioxide Capture: Beyond the Capacity-Stability Tradeoff.

Eutectic mixture (EM)-promoted MgO sorbents exhibit high CO sorption capacities but  experience a significant decrease in uptake after multiple sorption-regeneration cycles due to EM movement and redistribution at high temperatures. Encapsulation of a pseudoliquid, phase-changing EM promoter with MgO may thus prevent the loss of active interface by confining the EM within a fixed area inside a MgO shell. In this work, we successfully embedded an EM composed of KNO and LiNO in a MgO fiber matrix via core-shell electrospinning.

Eutectic mixture promoted CO sorption on MgO-TiO composite at elevated temperature.

The development of carbon dioxide (CO) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies. Recently, promoter-based systems composed of alkali/alkaline earth metal nitrates and/or carbonates have been considered as next-generation solid sorbents due to their improved CO uptake and kinetics. However, obtaining stable MgO sorbents against temperature swing regeneration still remained challenging.

Stabilization of NaNO-Promoted Magnesium Oxide for High-Temperature CO Capture.

NaNO-promoted MgO sorbents are known to achieve enhanced CO sorption uptake but fail to maintain their capacity after multiple sorption-regeneration cycles. In this study, commercially available hydrotalcites (Pural Mg30, Pural Mg70, and synthetic hydrotalcite) were used as stabilizers for NaNO-impregnated MgO (MgONaNO) sorbents to improve their cyclic stability. Results show that the Mg30-stabilized MgONaNO attained higher and stable overall CO sorption performance as compared to bare MgONaNO after multiple sorption cycles.

In Situ Observation of Carbon Dioxide Capture on Pseudo-Liquid Eutectic Mixture-Promoted Magnesium Oxide.

Eutectic mixtures of alkali nitrates are known to increase the sorption capacity and kinetics of MgO-based sorbents. Underlying principles and mechanisms for CO capture on such sorbents have already been established; however, real-time observation of the system was not yet accomplished. In this work, we present the direct-observation of the CO capture phenomenon on a KNO-LiNO eutectic mixture (EM)-promoted MgO sample, denoted as KLM, via in situ transmission electron microscopy (in situ TEM).