Low temperature solution synthesis of reduced two dimensional Ti₃C₂ MXenes with paramagnetic behaviour

MXenes - two dimensional, 2D, early transition metal, M, carbides and nitrides, X - are the latest addition to the 2D materials' world. Herein, we report on a facile low temperature solution chemical synthesis method to reduce Ti₃C₂T_x multilayered, ML, MXenes. Using X-ray photoelectron spectroscopy, electron spin resonance, magnetization measurements and other techniques, we concluded that immersing Ti₃C₂T_x MLs in the reducing agent Li-ethylenediamine (Li-EDA) - held at temperatures varying from room to 120 °C - reduces the 2D layers creating Ti³⁺ ions and oxygen vacancies. Above a temperature (T) of ≈10 K, the magnetic susceptibilities, χ, are temperature independent, implying that the resulting powders are Pauli paramagnetic. The loss of the magnetic signal upon intercalation of Li⁺ or EDA, together with a Curie-like increase in χ at T < 10 K, is consistent with that of a disordered metal that is close to a metallic to insulator transition and proves that the magnetism is associated with the 2D flakes. This result is the first evidence of any magnetism of any MXene.