A Systematic Approach to Understanding and Optimizing the CO₂ Capture Performance of Triamine-Functionalized Mesoporous Silica with Amine Blends Using Molecular Simulations

In this contribution, we apply molecular dynamics and Monte Carlo simulation techniques to study the CO₂ physisorption performance and predict the chemisorption performance by analyzing the accessibility and orientation of blended amine chains inside the mesoporous structure of silica KIT-6. We found that triamine chains form complex arrangements where the middle amine groups are isolated, hindering amine-amine proton transfer. Among all tested amine blends, short primary monoamine chains achieve the highest number of adsorbed CO₂ molecules per amine group (CO₂/N ratio) of 0.479, though all amine blends have higher overall CO₂ uptake and CO₂/N ratio than pure triamine. Results prove that the study of accessibility and orientation is beneficial to account for the CO₂ adsorption on amines and determine the kinetically favorable reaction pathways. Our methodology establishes a fast optimization technique for amine-functionalized silica materials for CO₂ capture applications.