Advanced Nitrides and MXene-Like Coatings Applied as Sensing Units in an Impedimetric E-Tongue Setup

MXenes exhibit unique properties that may catalyze significant scientific and technological advancements [1,2] due to their uncommon characteristic among similar materials. The versatility of combining transition metals enlarges promising features; however, the traditional MXene synthesis relies on harsh chemical methods, particularly hydrofluoric acid (HF) etching, which constrains further application. Plasma processes may be an interesting tool to change this paradigm, allowing very precise control of properties and a wide range of possibilities to be explored, including materials’ composition and system parameters. Based on that, our work aims to develop and validate a groundbreaking physical synthesis route for MXenes, eliminating the need for strong acids. This innovative method integrates multi-component targets with physical vapor deposition (PVD) and dynamic substrate angle control, providing enhanced control over thin film properties. Initial evaluations focus on CrN and TiN-based materials, with intentional surface terminations formed <i>in situ</i> to prevent undesired bonds and circumvent the traditional etching step. As we progress towards establishing a physical synthesis route for MXenes, we anticipate the emergence of intermediate materials, potentially free-standing nitrides and carbides. These MXene-like structures will be thoroughly characterized and explored to verify their properties and potential applications. As a proof of principle, preliminary results on using the developed materials to enhance impedimetric e-tongue sensing units will be presented. Achieving a physical synthesis route for MXenes has the potential to revolutionize the field, offering an environmentally friendly and versatile approach to material synthesis. This advancement could significantly enhance the applicability of MXenes in various domains, including sensing technologies, environmental monitoring, and beyond. Despite the promising outlook, numerous challenges remain, and continued research is essential to realize the full potential of this innovative green synthesis route.<br/><br/><b>References</b><br/>[1] Y. Gogotsi, Q. Huang, ACS Nano 15 (2021) 5775–5780. https://doi.org/10.1021/acsnano.1c03161.<br/>[2] M. Hu, H. Zhang, T. Hu, B. Fan, X. Wang, Z. Li, Chem Soc Rev 49 (2020) 6666–6693. https://doi.org/10.1039/d0cs00175a.<br/><br/><b>Acknowledgments:</b> UNICAMP, FAPESP (processes # 2023/07552-0 (L. M. Leidens) and # 2022/08216-1 (C. D. Boeira)), CNPq