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