MXenes | Drexel Engineering

Check out our new “About MXenes” handout [PDF] and learn all about MXenes.

Illustration of MXene properties — Scanning electron microscope image of multilayered Ti₃C₂ MXene. B. Anasori, et al. *Nature Reviews Materials*, 2017, 2, 16098.

MXenes are a family of two-dimensional (2D) inorganic compounds with the general formula of M_n₊₁X_nT_x, where M is an early transition metal, X is carbon and/or nitrogen, and T is a functional group on the surface of a MXene (typically O, OH and F) (M. Naguib, et al. Adv. Mater., 2014, 26, 992). MXenes have the high metallic conductivity of transition metal carbides, and are (unlike other 2D materials like graphene) hydrophilic because of their hydroxyl- and oxygen-terminated surfaces. MXenes were first discovered in 2011 at Drexel University, as a result of selectively etching the A layer out of bulk ternary transition metal carbides and nitrides, known as MAX phases, which yields multilayered MXenes. To increase surface area and accessibility of its surface, multilayered MXenes typically undergo further processing to yield solutions of delaminated MXenes.

Due to their hydrophilicity, MXenes can be processed in aqueous and polar organic solvents to form stable colloidal solutions that can be filtered to form freestanding films and spray-coated to form transparent conductive coatings. This provides a greater of potential applications for this family of materials. The first MXene discovered was Ti₃C₂ and it was initially investigated for its electrochemical properties in batteries and supercapacitors (B. Anasori, et al. Nature Reviews Materials, 2017, 2, 16098). In the past several years, however, over two dozen MXenes have been discovered along with dozens of other applications.

MXene applications that have been explored beyond energy storage include sprayable electromagnetic interference shielding, which it was found to be the best performing synthetic material for this application per thickness of material (F. Shahzad, et al. Science, 2016, 353 (6304): 1137). Other applications that have been found are sprayable antennas (A. Sarycheva, et al. Science Advances, 2018, 4(9), eaau0920.), several biomedical applications (K. Huang, et al. Chemical Society Reviews, 2018, 14, 5109), water purification (K. Rasool, et al. Materials Today, 2019. "Water treatment and environmental remediation applications of two-dimensional metal carbides (MXenes).") and beyond. Nitride MXenes, which are synthesized by different procedures than carbide MXenes, offer other potential applications due to their high electrical conductivity values and plasmonic properties (P. Urbankowski, et al. Nanoscale, 2017, 9(45), 17722). The world of MXene synthesis and application development is growing at a rapid rate. This family of materials has outperformed materials used in many applications and has the potential to transform the incorporation of nanotechnology in everyday life.

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