Thermokinetic evaluation of iron addition on lithium metazirconate (FeLi2ZrO3) for enhancing carbon dioxide capture at high temperatures

Pristine and different Fe-containing lithium zirconate samples were synthesized by solid-state reaction and characterized by different structural, microstructural and chemical techniques. X-ray diffraction showed that iron atoms were only partially incorporated into lithium zirconate, preserving the main crystal structure. The rest of iron atoms were superficially supported as iron oxide. Moreover, iron-containing samples slightly changed different microstructural characteristics, such as particle size and morphology. All samples were tested on CO2 chemisorption, using different dynamic, isothermal and cyclic experiments, in the presence or absence of oxygen. Results show that iron addition on Li2ZrO3 enhanced temperature range, kinetic and efficiency of CO2 chemisorption. Cyclic tests showed that CO2 chemisorption efficiency tended to increase on iron-containing samples. CO2 chemisorption improvements obtained by iron addition were explained due to partial Fe reduction, implying an oxygen release, and catalytic effect for oxygen dissociation (on oxygen presence), promoting the CO2 chemical transformation to carbonate ions.