Natu Varun, Hart James L, Sokol Maxim, Chiang Helen, Taheri Mitra L, Barsoum Michel W
Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA.
Angew Chem Int Ed Engl. 2019 Sep 2;58(36):12655-12660. doi: 10.1002/anie.201906138. Epub 2019 Aug 22.
MXenes have shown promise in myriad applications, such as energy storage, catalysis, EMI shielding, among many others. However, MXene oxidation in aqueous colloidal suspensions when stored in water at ambient conditions remains a challenge. It is now shown that by simply capping the edges of individual MXene flakes, Ti C T and V CT , by polyanions such as polyphosphates, polysilicates or polyborates, it is possible to quite significantly reduce their propensity for oxidation even when held in aerated water for weeks. This breakthrough resulted from the realization that the edges of MXene sheets are positively charged. It is thus an example of selectively functionalizing the edges differently from the MXene sheet surfaces.
MXenes在众多应用中展现出了潜力，比如能量存储、催化、电磁干扰屏蔽等等。然而，当在环境条件下储存于水中时，MXenes在水性胶体悬浮液中的氧化仍然是一个挑战。现在有研究表明，通过简单地用多聚阴离子（如多磷酸盐、聚硅酸盐或多硼酸盐）覆盖单个MXene薄片（Ti₃C₂Tₓ和V₂CTₓ）的边缘，即使将它们置于曝气水中数周，也能够显著降低其氧化倾向。这一突破源于认识到MXene薄片的边缘带正电荷。因此，这是一个对边缘进行选择性功能化的例子，与MXene薄片表面的功能化方式不同。
