Structural and CO2 Chemisorption Analyses on Na2(Zr1-xAlx)O3 Solid Solutions

Different sodium zirconate solid solutions containing aluminum (Na-2(Zr1-xAlx)O-3) 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 CO2 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 Na-2(Zr1-xAlx)O-3 ceramics exhibited high and stable CO2 capture behaviors.