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. Herein, we report MgO-TiO solid sorbents promoted by eutectic mixture (KNO and LiNO) for elevated temperature CO sorption. The developed sorbents show improved CO sorption capacity, which may be attributed to the alternative CO sorption pathway provided by the ionization of highly dispersed MgO in the eutectic mixture. The MgO-TiO framework was also shown to assist in retaining the MgO configuration by constraining its interaction with CO. Furthermore, it is demonstrated that constructing composite structures is essential to improve the CO sorption characteristics, mainly recyclability, at elevated temperatures. The developed promoter integrated sorbents showed exceptionally high CO sorption capacity of >30wt.% at an elevated temperature (300°C) with pronounced stability under temperature swing operation.