Structural and CO₂ chemisorption analyses on Na ₂(Zr_{1- x}Al_x)O₃ solid solutions

Different sodium zirconate solid solutions containing aluminum (Na ₂(Zr_1-xAl_x)O₃) were synthesized via a solid-state reaction. Samples were characterized using X-ray diffraction and solid-state nuclear magnetic resonance. Then, samples were tested as CO ₂ captors. Characterization results show that aluminum ions can occupy zirconium or sodium sites in the Na₂ZrO₃ structure. Thus, the aluminum dissolution is compensated by different structural defects. The CO₂ capture evaluation shows that the aluminum presence into the Na₂ZrO₃ structure improves the CO₂ chemisorption within certain aluminum content under specific thermal conditions. These results were corroborated with the kinetic analysis, where the activation enthalpies were determined. The CO₂ chemisorption differences were attributed to different sodium secondary phases produced in each case and their corresponding diffusion properties. Finally, cyclic performance tests indicate that Na₂(Zr_1-xAl_x)O₃ ceramics exhibited high and stable CO₂ capture behaviors.