Enhanced Thermal Oxidative Stability of multi-layer Ti3C2Tₓ Functionalized with Polyketones

Two-dimensional (2D) MXenes, such as Ti₃C₂Tₓ, are promising materials due to their high specific surface area, excellent electrical conductivity, and mechanical robustness. However, their applicability is limited by their tendency to restack and agglomerate as well as their poor oxidation resistance in oxygen-rich or -OH-containing environments, thus notably downgrading their structural, chemical, and electrical characteristics. In this study, the oxidative stability of multi-layer (ML) Ti₃C₂Tₓ (obtained via a two-step chemical functionalization strategy) was evaluated by thermal analysis. First, ML-Ti₃C₂Tₓ was decorated with primary amine groups using N1-(3- Trimethoxysilylpropyl)diethylenetriamine (TMSPDETA) with a standard silanization method and subsequently functionalized with aliphatic polyketones via the Paal-Knorr reaction. The functionalized ML-Ti₃C₂Tₓ were characterized by Raman spectroscopy, electron microscopy, and elemental analysis, while the thermo-oxidative stability was validated by thermogravimetric analysis coupled with infrared spectroscopy of the evolved gases. The polyketone-modified Ti₃C₂Tₓ displayed an increased onset temperature for oxidation (Tonset increased from 371 to 408 ◦C), while keeping the structural integrity of ML-Ti₃C₂Tₓ. Our results demonstrate that polymer grafting not only preserves the layered morphology of ML-Ti₃C₂Tₓ but also enhances its chemical stability, offering a scalable approach for improving the performance of MXenes in high-temperature and oxidative environments.