Abstract 2D MXenes have attracted extensive attentions owing to their anisotropy, high conductivity and other extraordinary properties. The popular preparation method of MXenes usually involves HF in high concentrations, which has seriously restricted their pervasive applications. In this work, a new hydrothermal route with low-toxicity etching agents (NaBF4, HCl) was used to synthesize Ti3C2 MXene (h-Ti3C2). Compared with the Ti3C2 prepared by the traditional HF etching method (t-Ti3C2), the h-Ti3C2 has the higher c lattice parameter, larger interlayer distance and larger BET specific surface area, because of the slow release mechanism during the hydrothermal process. The hydrothermal etching method not only avoided the use of high-concentration HF, but also was more efficient to prepare Ti3C2 flakes. Moreover, the hydrothermal etching route can be extended to other MXene materials, e.g. Nb2C. We demonstrated that the h-MXenes have better adsorption performance of methylene blue and methyl orange dyes. The hydrothermal etching route proposed in this study enabled the environmental benign and high efficiency exfoliation of MXenes, displaying the promise to facilely prepare 2D MXenes and paving a way to their widespread applications.

中文翻译：

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合成 2D MXene（Ti 3 C 2 、Nb 2 C）的水热蚀刻途径：增强剥离和改善吸附性能

摘要 2D MXenes 因其各向异性、高导电性和其他非凡的特性而受到广泛关注。MXenes 的流行制备方法通常涉及高浓度的 HF，这严重限制了其普遍应用。在这项工作中，使用一种新的水热路线和低毒蚀刻剂（NaBF4，HCl）合成 Ti3C2 MXene（h-Ti3C2）。与传统 HF 蚀刻法制备的 Ti3C2（t-Ti3C2）相比，h-Ti3C2 具有更高的 c 晶格参数、更大的层间距和更大的 BET 比表面积，这是由于水热过程中的缓释机制。水热蚀刻法不仅避免了高浓度HF的使用，而且制备Ti3C2薄片的效率更高。而且，水热蚀刻路线可以扩展到其他 MXene 材料，例如 Nb2C。我们证明了 h-MXenes 对亚甲基蓝和甲基橙染料具有更好的吸附性能。本研究中提出的水热蚀刻路线使 MXenes 的环境良性和高效剥离，显示出轻松制备 2D MXenes 的前景，并为其广泛应用铺平了道路。