Organosodium-derived Na2ZrO3 sorbents for low-concentration CO2 capture: An experimental and DFT study

• Organosodium-derived Na 2 ZrO 3 was synthesized and exhibited enhanced CO 2 capture performance. • The modification of organic sodium resources increased the amount of small mesopores that can accelerate the sorption reaction rate. • The kinetic analysis based on double exponential model was conducted and the activation energies for the surface chemisorption and bulk diffusion stage were calculated. • The CO 2 chemisorption mechanism of Na 2 ZrO 3 was firstly analyzed by DFT calculation. In recent years, the development of novel solid materials for high-temperature CO 2 capture has garnered worldwide attention. The advancement and investigation of Na 2 ZrO 3 -based sorbents have provided a novel technological route and application potential for industrial CO 2 removal. However, the unsatisfactory capacity and unclear sorption mechanism hinder its further development. In this work, organosodium-derived Na 2 ZrO 3 was synthesized, and the CO 2 sorption performance exhibited obvious enhancement with the total CO 2 capacity increased by 20.69 % even under 15 vol% CO 2 atmospheres. In addition, the modification mechanism of organic sodium sources as well as the reaction behavior between Na 2 ZrO 3 and CO 2 was investigated via kinetic analysis and various characterization techniques. Sorbents derived from organic sodium sources, characterized by a significant amount of small mesopores (3–4 nm), exhibited high reaction rates during the superficial chemisorption stage. Besides, the CO 2 sorption reaction was described via the double-shell model, and the activation energies for the superficial chemisorption and bulk diffusion stages were calculated to be 30.2 kJ/mol and 54.3 kJ/mol, respectively. Finally, the CO 2 chemisorption mechanism of Na 2 ZrO 3 was studied via density functional theory (DFT) calculations for the first time. Chemisorption was the product of bonding between C atom of CO 2 molecule and O atom on the surface, and O atom was the main active center for the chemisorption. Generally, this study proposed an effective route for the production of structurally-improved Na 2 ZrO 3 sorbents for efficient CO 2 capture, and the sorption mechanisms were thoroughly studied from the macro to the micro level.