Ab-initio investigation of the swelling behavior of Montmorillonite clay and MXenes in the presence of cations.

The swelling behavior of naturally occurring clays like Montmorillonite (MMT) is crucial because it can greatly impact the physical characteristics of soil and rock formations, potentially causing issues in construction and land stability. We conducted ab-initio calculations using VASP to explore this swelling behavior in bi-layer montmorillonite (MMT) clay and compared it to a heterostructure where one MMT layer is replaced by a Ti3C2O MXene layer. To neutralize the negative charge, Na+ cations were placed between the layers. We examined the changes in basal spacing, the nature and strength of atomic bonds, and the overall swelling behavior of both materials as the intercalation of water (H2O) and Na+ ions between the layers increased. The findings from this research offer insights into the potential suitability of Clay-MXene heterostructures for enhancing stability in such applications.