The properties of MXene flakes, a new class of two-dimensional materials, are strictly determined by their surface termination. The most common termination groups are oxygen-containing (═O or –OH) and fluorine (−F), and their relative ratio is closely related to flake stability and catalytic activity. The surface termination can vary significantly among MXene flakes depending on the preparation route and is commonly determined after flake preparation by using X-ray photoelectron spectroscopy (XPS). In this paper, as an alternative approach, we propose the combination of surface-enhanced Raman spectroscopy (SERS) and artificial neural networks (ANN) for the precise and reliable determination of MXene flakes’ (Ti₃C₂T_x) surface chemistry. Ti₃C₂T_x flakes were independently prepared by three scientific groups and subsequently measured using three different Raman spectrometers, employing resonant excitation wavelengths. Manual analysis of the SERS spectra did not enable accurate determination of the flake surface termination. However, the combined SERS-ANN approach allowed us to determine the surface termination with a high accuracy. The reliability of the method was verified by using a series of independently prepared samples. We also paid special attention to how the results of the SERS-ANN method are affected by the flake stability and differences in the conditions of flake preparation and Raman measurements. This way, we have developed a universal technique that is independent of the above-mentioned parameters, providing the results with accuracy similar to XPS, but enhanced in terms of analysis time and simplicity.

中文翻译：

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用于检测 MXene 薄片表面终端的表面增强拉曼光谱和人工神经网络

MXene 薄片是一类新型二维材料，其性能严格由其表面终止决定。最常见的终止基团是含氧（=O或-OH）和氟（-F），它们的相对比例与薄片稳定性和催化活性密切相关。根据制备途径的不同，MXene 薄片之间的表面终止可能存在显着差异，并且通常在薄片制备后使用 X 射线光电子能谱 (XPS) 来确定。在本文中，作为一种替代方法，我们提出结合表面增强拉曼光谱 (SERS) 和人工神经网络 (ANN) 来精确可靠地测定 MXene 薄片 (Ti ₃ C ₂ T _x ) 的表面化学性质。 Ti ₃ C ₂ T _x薄片由三个科学小组独立制备，随后使用三个不同的拉曼光谱仪采用共振激发波长进行测量。 SERS 光谱的手动分析无法准确确定薄片表面终止。然而，结合 SERS-ANN 方法使我们能够高精度地确定表面终止。通过使用一系列独立制备的样品验证了该方法的可靠性。我们还特别关注了 SERS-ANN 方法的结果如何受到薄片稳定性以及薄片制备和拉曼测量条件差异的影响。通过这种方式，我们开发了一种独立于上述参数的通用技术，提供的结果与 XPS 相似，但在分析时间和简单性方面有所增强。