First assessment of Li₂O–Bi₂O₃ ceramic oxides for high temperature carbon dioxide capture

The capacity to capture CO₂ was determined in several stoichiometric compositions in the Li₂O–Bi₂O₃ system. The compounds (Li₇BiO₆, Li₅BiO₅, Li₃BiO₄ and LiBiO₂ phases) were synthesized via solid-state reaction and characterized by X-ray diffraction, scanning electron microscopy and N₂ adsorption techniques. The samples were heat-treated at temperatures from 40 to 750 °C under the CO₂ atmosphere to evaluate the carbonate formation, which is indicative of the capacity of CO₂ capture. Moreover, Li₇BiO₆ shows an excellent CO₂ capture capacity of 7.1 mmol/g, which is considerably higher than those of other previously reported ceramics. Li₇BiO₆ is able to react with CO₂ from 240 °C to approximately 660 °C showing a high kinetic reaction even at CO₂ partial pressure values as low as 0.05.