Yury Gogotsi, Drexel University
Synthesis of 2D Transition Metal Carbides and Nitrides (MXenes)
Written by Mohit Saraf
Yury Gogotsi highlighted the importance of synthesis of MXenes from environmentally friendly, safe, efficient, and scalable methods. Typically, MXenes are synthesized from MAX phases by etching with acids (HF and HCl) followed by delamination. Their properties can be controlled by tuning their compositions and structures. They are hydrophilic, easily dispersible in water, strong, stiff and possess high electrical conductivity, making them suitable for a wide range of applications. However, the synthesis of MXenes may have some challenges such as use of HF acid, which is highly corrosive and dangerous for the human body and, therefore, the safety is equally important. This requires safety equipment which makes the overall synthesis process expensive. Therefore, safer, and environmentally stable synthesis is important. Gogotsi also emphasized the computational approaches of predicting the exfoliability of MAX phases. He said that different MXenes require different reaction parameters and therefore the exfoliation energy and etching parameters need to be adjusted and therefore the guidance from computational studies is important. He mentioned that stoichiometry of MXenes is also important and usually MXenes inherit the characteristics of MAX phases. The selective etching of MAX phases is important, and he discussed etching and delamination mechanisms. Gogotsi said that as per his knowledge, MXenes are the only nanomaterials which can be produced in kilogram of scale meaning true industrial scale applications can be addressed. Lastly, he mentioned several new MXene synthesis protocols coming up such as molten-salt synthesis which are relatively safer. Overall, he emphasized the simpler, safer, scalable, and environmentally stable synthesis of MXenes.