Exploitation of N, S co-doped carbon spheres for good CO2 adsorption capacity and high adsorption selectivity

In recent years, CO 2 adsorption technology has garnered widespread attention, making the development of efficient CO 2 adsorbents a critical issue. This study has synthesized N, S co-doped carbon spheres (NxSyCz) using hydrothermal, impregnation, and one-step carbonization-activation methods, and systematically investigated their CO 2 adsorption performance. Characterization results reveal that NxSyCz possesses a rich microporous structure and a high specific surface area, with nitrogen and sulfur elements successfully doped into the carbon framework in various forms. Furthermore, CO 2 adsorption experiments demonstrate that NxSyCz exhibits excellent static CO 2 adsorption capacity (3.42 mmol/g at 298.15 K) and superior dynamic CO 2 adsorption capacity (3.08 mmol/g at 318.15 K). Additionally, NxSyCz displays good cyclic regeneration performance and high CO 2 /N 2 adsorption selectivity (IAST Selectivity = 117). Density Functional Theory (DFT) calculations further confirm that the presence of N and S functional groups significantly enhances the CO 2 adsorption selectivity of the adsorbent. Overall, the doping of N and S elements, along with the formation of a rich microporous structure, greatly enhances the CO 2 adsorption capacity of NxSyCz. Therefore, NxSyCz is expected to have promising applications in the field of CO 2 separation from coal-fired flue gases.