Understanding the CO2 chemical reaction path on Li6ZnO4, a new possible high temperature CO2 captor

Li6ZnO4 was synthesized, structural and microstructurally characterized and tested as possible carbon dioxide (CO2) chemical captor. The structural analysis suggests that Li6ZnO4 may have high Li-ion diffusion, based on its crystal triangle gap area measurement, which is among the highest ones analyzed within this context. Thus, Li6ZnO4 was dynamic and isothermally tested under different CO2 partial pressures (1.0 and 0.2) in the presence or absence of oxygen, through thermogravimetric techniques. Li6ZnO4 exhibited excellent CO2 chemisorption efficiencies, even when the CO2 partial pressure was as low as 0.2. Moreover, the kinetic analyzed was performed using the modified Jander-Zhang model, showing fast and efficient CO2 carbonation, where the kinetics enhanced as a function of the CO2 concentration, as it would be expected. The XRD analysis of the isothermal products allowed to determine the CO2 chemisorption reaction path, where an intermediate Li10Zn4O9 crystal phase was observed. Thus, a topochemical lithium release was assumed to explain the whole Li6ZnO4 carbonation process, supported by the crystal structure analysis. Additionally, a cyclic Li6ZnO4 carbonation-decarbonation test evidenced interesting efficiencies, of around 60.0% after 10 cycles.

Automated summary

Li6ZnO4 showed excellent CO2 chemisorption efficiency even at low CO2 partial pressures. The kinetic analysis revealed fast and efficient CO2 carbonation, with a cyclic test demonstrating around 60.0% efficiency after 10 cycles.