Anisotropy in Carbon Dioxide Adsorption on Forsterite.

In this study, density functional theory (DFT) method were used to investigate the adsorption behavior and binding mechanism of CO2 molecules on six crystallographic surfaces of forsterite (Mg2SiO4). The influence of surface crystallographic orientation on CO2 adsorption efficiency was examined at the atomic level. Results showed stable binding of CO2 on all surfaces. The interaction strength decreases in the order: (001) > (101) > (120) > (111) > (010) > (110), with the (001) surface exhibiting the highest binding capacity due to accessible magnesium cations interacting with CO2. Detailed electronic property analysis revealed significant charge transfer between CO2 oxygen atoms and surface magnesium atoms, driven by hybridization of oxygen 2p and magnesium 2s orbitals, leading to the formation of ionic and covalent bonds. These interactions stabilize the adsorbed CO2 and are accompanied by changes in the electronic structure, such as energy level shifts and modifications in the partial density of states (PDOS). The computational analysis provides a theoretical foundation for understanding CO2 binding mechanisms by forsterite. The findings highlight the importance of crystallographic orientation and electronic properties of the mineral surface in adsorption efficiency, contributing to a deeper understanding of CO2 interactions with mineral surfaces.