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

Different sodium zirconate solid solutions containing aluminum (Na 2 (Zr 1– x Al x )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 CO 2 captors. Characterization results show that aluminum ions can occupy zirconium or sodium sites in the Na 2 ZrO 3 structure. Thus, the aluminum dissolution is compensated by different structural defects. The CO 2 capture evaluation shows that the aluminum presence into the Na 2 ZrO 3 structure improves the CO 2 chemisorption within certain aluminum content under specific thermal conditions. These results were corroborated with the kinetic analysis, where the activation enthalpies were determined. The CO 2 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 (Zr 1– x Al x )O 3 ceramics exhibited high and stable CO 2 capture behaviors.