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.