Kumar Jai, Tan Jiayi, Soomro Razium Ali, Sun Ning, Xu Bin
State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology Beijing 100029 China
School of Energy Science and Technology, Henan University Zhengzhou 450046 China.
Chem Sci. 2024 Dec 16;16(4):1986-1994. doi: 10.1039/d4sc05097e. eCollection 2025 Jan 22.
The shelf life of 2D MXenes in functional devices and colloidal dispersions is compromised due to oxidation in the aqueous system. Herein, a systematic investigation was carried out to explore the potential of various amino compounds as antioxidants for TiCT MXenes. A range of basic, acidic, and neutral amino acids were examined for their effectiveness, where certain antioxidants failed to protect MXenes from oxidation, while others accelerated their decomposition. Serine, threonine, and asparagine demonstrated excellent antioxidant activity, likely due to their evenly distributed molecular charges. These neutral amino acids outperformed glutamic acid, which possesses an electron-withdrawing COOH group, and lysine, with an electron-donating NH group. Serine-functionalized MXene realized a stabilization time constant reaching 128 days, as determined by first-order reaction kinetics. Additionally, when employed as supercapacitor electrodes, aged MXene and serine-functionalized MXene exhibited specific capacitance values of 219.2 and 280.3 F g at 5 A g after 6 weeks, respectively. This work addresses the gap in the practical work on ionic stabilization of 2D MXenes and has significant implications for the long-term colloidal storage of MXenes using greener chemicals.
二维MXenes在功能器件和胶体分散体中的保质期会因水体系中的氧化作用而缩短。在此，我们进行了一项系统研究，以探索各种氨基化合物作为TiCT MXenes抗氧化剂的潜力。我们考察了一系列碱性、酸性和中性氨基酸的有效性，其中某些抗氧化剂无法保护MXenes免受氧化，而其他一些则加速了它们的分解。丝氨酸、苏氨酸和天冬酰胺表现出优异的抗氧化活性，这可能是由于它们分子电荷分布均匀。这些中性氨基酸的表现优于具有吸电子COOH基团的谷氨酸和具有供电子NH基团的赖氨酸。通过一级反应动力学测定，丝氨酸功能化的MXene实现了长达128天的稳定时间常数。此外，当用作超级电容器电极时，老化的MXene和丝氨酸功能化的MXene在6周后、电流密度为5 A g时的比电容值分别为219.2和280.3 F g。这项工作填补了二维MXenes离子稳定化实际工作中的空白，对于使用更环保化学品对MXenes进行长期胶体储存具有重要意义。
