Thermokinetic evaluation of iron addition on lithium metazirconate (Fe-Li2ZrO3) for enhancing carbon dioxide capture at high temperatures

Highlights: • Fe-containing Li₂ZrO₃ samples were synthesized characterized by different techniques. • Fe addition importantly improved the CO₂ chemisorption on Li₂ZrO₃. • CO₂ chemisorption improvements were explained due to partial Fe reduction. -- Abstract: 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.