Enhanced CO₂ Adsorption Performance on Hierarchical Porous ZSM-5 Zeolite

Hierarchical porous ZSM-5 (HP-ZSM-5) was constructed using organosilanes as the growth inhibitors for CO₂ capture. The properties of adsorbents were characterized by X-ray diffraction, N₂ adsorption/desorption, scanning electron microscopy, temperature-programmed desorption of carbon dioxide, and ²⁷Al magic angle spinning nuclear magnetic resonance. It was found that HP-ZSM-5 samples synthesized by organosilanes had a significant effect on the microstructure and morphology. CO₂ adsorption capacity of HP-ZSM-5 was up to 58.26 cm³ g^-1 at 0 °C and 1 bar, significantly higher than that of the ZSM-5 sample. The effective improvement of CO₂ adsorption performance mainly originated from the micro-/mesoporous composite structure and complex surface morphology, which can provide low-resistant pathways for CO₂ through the porous network. Besides, in situ Fourier transform infrared spectroscopy was carried out to study the adsorption process on adsorbents, and the results indicated that a faster physical adsorption process was achieved as a result of the introduction of mesopores.