Computational studies have played a pivotal role in understanding the properties of MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides. Density functional theory (DFT) and molecular dynamics (MD) simulations have been instrumental in predicting their mechanical, electronic, and catalytic behaviors, often providing insights that guide experimental validation. These computational approaches have helped uncover fundamental characteristics that make MXenes promising for applications in energy storage, catalysis, and electronics.

Mechanical properties of MXenes have been extensively investigated using DFT and MD simulations. MXenes exhibit exceptional mechanical strength and flexibility, with Young’s modulus values ranging between 300 and 500 GPa for materials like Ti3C2Tx, depending on functionalization. DFT calculations reveal that the presence of surface terminations, such as -O, -F, or -OH groups, influences mechanical stability. For instance, oxygen-terminated MXenes generally show higher stiffness compared to their fluorine or hydroxyl-terminated counterparts. MD simulations further demonstrate that MXenes can withstand significant tensile strain before fracture, with some compositions retaining structural integrity up to 15% strain. These predictions align well with experimental nanoindentation and atomic force microscopy measurements, confirming their robustness.

Electronic properties of MXenes are highly tunable, as revealed by DFT studies. The electronic structure of MXenes is sensitive to surface functional groups, layer thickness, and transition metal composition. For example, Ti3C2Tx is predicted to be metallic, while Mo2CTx can exhibit semiconducting behavior depending on surface termination. DFT calculations show that the work function of MXenes can be modulated between 3.5 and 5.5 eV, making them suitable for electrode applications in electronic devices. Bandgap engineering via surface functionalization has been computationally demonstrated, with oxygen-terminated MXenes often showing wider bandgaps than their bare counterparts. Experimental studies using angle-resolved photoemission spectroscopy (ARPES) and transport measurements corroborate these findings, validating the metallic or semiconducting nature predicted by simulations.

Catalytic properties of MXenes have been a major focus of computational investigations. DFT studies highlight the role of MXenes as efficient electrocatalysts for reactions such as hydrogen evolution (HER), oxygen reduction (ORR), and carbon dioxide reduction (CO2RR). The basal planes and edges of MXenes exhibit distinct catalytic activities, with transition metal sites acting as active centers. For HER, Ti3C2Tx MXenes are predicted to have Gibbs free energy values close to zero for hydrogen adsorption, a key indicator of high catalytic efficiency. Similarly, nitrogen-doped MXenes show enhanced ORR activity due to favorable charge redistribution. These computational insights have been validated by experimental electrochemical measurements, where MXene-based catalysts demonstrate low overpotentials and high current densities.

Thermal stability and phonon transport in MXenes have also been explored using MD and DFT. Simulations predict that MXenes maintain structural stability at elevated temperatures, with decomposition temperatures exceeding 1000 K for certain compositions. Phonon dispersion calculations indicate anisotropic thermal conductivity, with in-plane values significantly higher than cross-plane due to strong covalent bonding within layers. Experimental thermogravimetric analysis and Raman spectroscopy confirm the thermal resilience predicted by simulations, while thermal conductivity measurements align with computational results.

Interfacial interactions between MXenes and other materials have been modeled to understand heterostructure behavior. DFT studies reveal that MXenes form stable interfaces with graphene, hexagonal boron nitride, and transition metal dichalcogenides, often leading to charge transfer and modified electronic properties. For instance, Ti3C2Tx/graphene heterostructures exhibit enhanced electrical conductivity due to interfacial coupling. Experimental fabrication of such heterostructures and subsequent characterization validate the computational predictions, demonstrating improved performance in devices like supercapacitors and sensors.

The role of defects in MXenes has been systematically investigated through computational methods. DFT simulations show that vacancies, adatoms, and grain boundaries can locally alter electronic and mechanical properties. Single vacancies in the carbon or nitrogen sublattice introduce mid-gap states, while metal vacancies may enhance catalytic activity by creating undercoordinated sites. MD simulations further reveal that defect migration is limited at room temperature, contributing to structural stability. Experimental observations using high-resolution transmission electron microscopy (HRTEM) confirm the presence and impact of defects, matching computational predictions.

Charge storage mechanisms in MXenes for battery and supercapacitor applications have been elucidated through DFT and MD. Simulations predict high capacitance values, often exceeding 1000 F/cm3, due to the combination of redox reactions and ion intercalation. The interlayer spacing and surface chemistry are found to critically influence ion diffusion kinetics. Experimental electrochemical testing validates these findings, with MXene electrodes demonstrating high volumetric capacitance and rate capability.

In summary, computational studies using DFT and MD have provided profound insights into the mechanical, electronic, and catalytic properties of MXenes. These predictions have been consistently validated by experimental measurements, reinforcing the reliability of theoretical approaches. The synergy between computation and experiment continues to drive advancements in MXene research, enabling tailored design for next-generation technologies.