Thinking green with 2-D and 3-D MXenes: Environment friendly synthesis and industrial scale applications and global impact

MXenes are currently a research hotspot in the field of 2D materials, hinting to revolutionize material technology. Their layered architecture allows for molecular intercalation, defect engineering, and surface band gap functionalization, with applications as diverse as energy storage and drinking water desalination. Its structural and functional integrity has prompted the scientific community to investigate novel compositions in an effort to leverage electrochemical activity, mechanical robustness, flexibility and environmental stability. However, the current synthesis routes present a bottleneck in proposing MXenes as a sustainable material for the future. Therefore, by expanding the reach of synthetic chemistry towards efficient strategies for green production, we present the first comprehensive introspection of the use of green solvents and their impact on material properties during MXene synthesis. This review is an attempt to quantify the intriguing characteristics of MXene nanocomposites by embracing design tools like the ‘iceberg model’. To further evaluate the performance of MXenes fabricated using green strategies (such as eutectic etching) we have made an attempt to critically compare them with conventional MXenes by examining surface characteristics, electrochemical analysis, charge transfer mechanisms etc. Conclusively, we aim to instigate concern about the environmental impact of MXene synthesis and instil a multidisciplinary approach to tailor environmentally benign, scalable and efficient MXene derivatives for commercial energy applications. The review provides an immersive account linking UN sustainable development goals with the industrial outlook of green MXenes, it highlights their impact on climate change, potential to build technically advanced economies, low cost production and range of applications.