Dual-mesopore mode and surface hydrogen bonding synergistic boosting CO2 adsorption

To address the limitation of mono-pore mode SBA-15 on adsorption efficiency and the aggregation of amine groups within the confined pores, an innovative TEOS hydrolysis-driven dual-pore strategy to fabricate SBA-15-Dual-Mesopore (SBA-DMP) structure with covalent-grafted of 3-trimethoxysilylpropan-1-amine (APTMS) is proposed. Structural and thermodynamic characterizations reveal that this dual-mesopore design provides more CO 2 adsorption sites, and the larger mesopores exhibit a strong affinity for tetraethylenepentamine (TEPA) that significantly enhances its dispersion and incorporation efficiency. Of noted, for the first time, electron paramagnetic resonance (EPR) spectroscopy is employed to study the electronic interactions within amine-functionalized materials, indicating that APTMS-induced surface hydrogen bonds facilitate lone pair electron delocalization through electronic rearrangement, improving the local electronic density around secondary amines. Microcalorimetric studies, along with temperature-programmed desorption (TPD) and density functional theory (DFT) calculations, confirm that hydrogen bonding significantly enhances the reactivity of secondary amines, leading to a high CO 2 adsorption capacity of 5.83 mmol g −1 at 70 °C under 10 % CO 2 (60 % RH). The comprehensive evaluation of the SBA-DMP material demonstrates an excellent amine efficiency, adsorption stability, recyclability, and selectivity, highlighting its suitability for practical CO 2 capture. The dual-mesopore design with surface hydrogen bonding collectively advances CO 2 adsorption efficiency, offering a practical and effective solution for carbon capture.