2D-Transition Metal Carbides and Nitrides: Materials for the Next Generation
Nilmani Kumar, Harpreet Singh, Madhu Khatri, Neha Bhardwaj
Abstract
MXenes are two-dimensional (2D) transition-metal carbides and nitrides which have received great attention since their discovery in 2011. They have a unique layered structure, rich elemental compositions, abundant surface functional groups, and exhibit pronounced electrical conductivity and optical properties. During the last decade, around 30 MXenes have been experimentally produced, and many more have been predicted theoretically. They possess inherent terminations on surfaces such as -O, -OH, and -F groups that are different from the parent MAX phase. MXenes provide an intriguing combination of mechanical, electronic, chemical, and optical properties that are well-suited for advanced applications. They have been extensively studied in optoelectronics, energy conversion and storage, water remediation, photonics, wearables, catalysis, sensors, electronics, biomedicine, and many other areas. The good flexibility of MXenes in combination with their 2D morphology and layered structure makes it easy for them to form composites with other materials, resulting in the integration of their outstanding properties. In this context, the present chapter will highlight the significant advancements in the MXenes field and their prospective applications in emerging scientific areas. The different synthesis routes, surface chemistry, and properties of MXenes are also discussed briefly. Finally, this work describes the challenges and limitations that prevent scientists from realizing the functional MXenes with controlled properties and structures.