Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746, South Korea.
Nanoscale. 2018 Dec 21;10(47):22429-22438. doi: 10.1039/c8nr06854b. Epub 2018 Nov 26.
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 TiCT multilayered, ML, MXenes. Using X-ray photoelectron spectroscopy, electron spin resonance, magnetization measurements and other techniques, we concluded that immersing TiCT MLs in the reducing agent Li-ethylenediamine (Li-EDA) - held at temperatures varying from room to 120 °C - reduces the 2D layers creating Ti 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.
MXenes-二维，2D，早期过渡金属，M，碳化物和氮化物，X-是二维材料世界的最新成员。在这里，我们报告了一种简便的低温溶液化学合成方法，用于还原 TiCT 多层，ML，MXenes。通过 X 射线光电子能谱、电子顺磁共振、磁化率测量和其他技术，我们得出结论，将 TiCT ML 浸入还原剂 Li-乙二胺（Li-EDA）中-保持在从室温到 120°C 的温度下-还原二维层，生成 Ti 离子和氧空位。在温度（T）约为 10 K 以上时，磁化率 χ 与温度无关，这意味着所得粉末是 Pauli 顺磁体。在 Li 或 EDA 插层时失去磁信号，以及在 T < 10 K 时 χ 呈类居里增加，与接近金属-绝缘体转变的无序金属一致，并证明磁与 2D 薄片有关。这一结果是任何 MXene 都具有任何磁性的第一个证据。
