Vacuum assisted desorption of sodium zirconate sorbent for enhancing cyclic stability in pre-combustion CO2 capture

• Cyclic CO 2 capacity decay results from incomplete reversion from Na 2 CO 3 to Na 2 ZrO 3 . • Vacuum desorption is beneficial to the cyclic CO 2 capture by Na 2 ZrO 3 . • Vacuum desorption favors the reversion of Na 2 ZrO 3 to the monoclinic state. • The special dislocation-stacked structure of monoclinic Na 2 ZrO 3 is simulated by MS. • The enhanced stability shows potential in-situ CO 2 capture in pre-combustion. Sodium zirconate (Na 2 ZrO 3 ) is a promising material for pre-combustion CO 2 capture due to its fast sorption kinetics and excellent cyclic stability at high temperatures under ideal condition (desorption in 100% N 2 ). Still, there is a lack of study on the performance of Na 2 ZrO 3 cyclic capture under harsh condition (desorption in high concentration CO 2 ). In this study, Na 2 ZrO 3 was prepared by wet-mixing and heated-drying, and the difference in the cyclic CO 2 capture performance of the sample was compared between desorption under harsh condition and vacuum condition. The crystal structure of Na 2 ZrO 3 was identified during the sorption-desorption cycles. The crystal structure was also modeled and simulated to analyze the reason for the superior capture performance from the monoclinic Na 2 ZrO 3 . It was found that the special interlocked and multilayered stacked structure of the monoclinic Na 2 ZrO 3 allowed for high reactivity with CO 2 . It was found that high temperature solely had little help in the desorption of Na 2 ZrO 3 under harsh condition, but vacuum condition promoted desorption of Na 2 ZrO 3 in high fraction CO 2 , and vacuum desorption at 1000 °C-1050 °C resulted in Na 2 ZrO 3 with both good capture performance and cycling stability. Vacuum desorption led to more complete reversion of Na 2 ZrO 3 to the monoclinic state, benefiting for CO 2 capture. This study attempted to simulate the harsh capture environments of real industrial applications and to explore the possibility of Na 2 ZrO 3 as a carbon capture material for pre-combustion capture.