From 2D MXenes to 3D Carbides: Transformation of Ti₃C₂T_z Thin Films into TiC_x Carbide Nanolayers

MXenes are renowned for their versatile uses in various scientific fields as 2D materials, but they also show potential in structural applications utilizing their high-temperature transformation into transition-metal carbides with unique morphologies. Herein, we developed a method to study this transformation in model systems. As a proof-of-concept, MXene thin films (≤20 nm thickness) were deposited on sapphire and subjected to high temperature (1400 °C) and moderate pressure (18 MPa), transforming them into nanolamellar carbides. Structural and compositional analyses of the interface revealed that the Ti₃C₂T_z transformed into TiC_xO_y (with ∼13 at% O), while halide surface terminations were removed. A small fraction of Li (∼0.2 at%) was detected within the transformed nanolayer, stabilized by the presence of O in the oxycarbide lattice. Ultimately, this methodology provides a framework for studying the MXene-to-MX transformation under controlled conditions, enabling the rational design of nanocomposites and bonding nanolayers for advanced structural and functional materials.