Recent advances in transition metal carbides and nitrides (MXenes): Characteristics, environmental remediation and challenges

MXenes, as newly emerging two-dimensional (2D) transition metal carbides and nitrides, have become promising candidates for environmental remediation and detection due to their hydrophilicity, metallic conductivity, versatile surface chemistry and 2D layered atomic structure. Nevertheless, little attention has been paid to the relationship between the properties of MXenes and their environmental performances. Herein, based on the recent experimental and theoretical research, a systematic review about the environmental applications of MXenes and MXenes-based materials including the removal and detection of toxic metal ions and organic contaminants, capture and mitigation of gas, hydrogen production, membrane- based separation, and disinfection has been done. Various design strategies of MXenes on ameliorating application performance are mentioned, and their suitability in multifarious environmental applications is thoroughly discussed. Based on the specific requirements of the final environmental applications, a targeted description between their properties and their abilities for environmental application is provided. Finally, current challenges and perspectives in this field are proposed from our personal insights. Particular emphasis in this review is directed toward the importance of understanding ultimate the aim and the required attributes to develop the proper materials for specific applications, and facilitates the further evolution of MXenes in environmental applications.