N-doped carbon sphere-SiO2 composite structure materials with high adsorption rate and low regeneration energy consumption for CO2 capture from flue gas

N-doped carbon-silicon composite adsorbent (NC@SiO 2 ) has garnered significant attention in the field of CO 2 capture. In this study, a novel NC@SiO 2 has been developed by combining hydrothermal synthesis, Stober method, and one-step carbonization activation. It exhibits a moderate static adsorption capacity (3 mmol/g, 298.15 K) , along with low adsorption heat (14.65–21.93 KJ/mol). At 313.15 K, the dynamic adsorption capacity and adsorption rate for CO 2 (volCO 2 : volN 2 = 15 %:85 %) are 2 mmol/g and 0.202 mmol/g/min, respectively. Additionally, it demonstrates excellent cycle stability, with the adsorption capacity decreasing by only 7 % after 10 cycles. Density Functional Theory (DFT) calculations confirm that the presence of functional groups of N and O significantly enhances CO 2 adsorption performance of NC@SiO 2 . The synergistic effect of SiO 2 coating, N doping, and K 2 CO 3 activation is important for improving CO 2 dynamic adsorption performance, positioning NC@SiO 2 as a promising candidate for capturing CO 2 from flue gas.