(618f) Oxidation and Stabilization of 2D Mxene Nanosheets

MXenes, such as Ti₃C₂T_x, are fascinating 2D nanomaterials with an attractive combination of functional properties suitable for applications such as batteries, supercapacitors, and strain sensors. However, practical uses of MXenes, such as Ti₃C₂T_x, remains challenging as these nanosheets are known to oxidize and degrade quickly from reacting with water and dissolved oxygen. Here, we examine oxidation of MXene nanosheets in various media (air, liquid, and solid) via multiple types of measurements to assess their shelf stability. The oxidation rate of MXene nanosheets were observed fastest in liquid media and slowest in solid media and can be accelerated by exposure to UV light. We also demonstrate an effective method to retard the oxidation of colloidal Ti₃C₂T_x MXene nanosheets by introducing antioxidants such as sodium L-ascorbate. The success of the method is evident in the conductivity and colloidal stability of Ti₃C₂T_x.Even in the presence of water and oxygen, the electrical conductivity of Ti₃C₂T_x nanosheets treated with sodium L-ascorbate was orders of magnitude higher as compared to untreated ones after 21 days. Our findings have the potential to be generalized to protect other types of MXenes as well and solve the most pressing challenge in the field of MXene engineering.