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pH, Nanosheet Concentration, and Antioxidant Affect the Oxidation of Ti 3 C 2 T x and Ti 2 CT x MXene Dispersions
Author(s) -
Zhao Xiaofei,
Vashisth Aniruddh,
Blivin Jackson W.,
Tan Zeyi,
Holta Dustin E.,
Kotasthane Vrushali,
Shah Smit A.,
Habib Touseef,
Liu Shuhao,
Lutkenhaus Jodie L.,
Radovic Miladin,
Green Micah J.
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202000845
Subject(s) - nanosheet , aqueous solution , materials science , citric acid , degradation (telecommunications) , dispersion (optics) , kinetics , chemical engineering , inorganic chemistry , ionic bonding , redox , nanotechnology , chemistry , ion , organic chemistry , telecommunications , physics , engineering , quantum mechanics , computer science , optics
The chemical stability of 2D MXene nanosheets in aqueous dispersions must be maintained to foster their widespread application. MXene nanosheets react with water, which results in the degradation of their 2D structure into oxides and carbon residues. The latter detrimentally restricts the shelf life of MXene dispersions and devices. However, the mechanism of MXene degradation in aqueous environment has yet to be fully understood. In this work, the oxidation kinetics is investigated of Ti 3 C 2 T x and Ti 2 CT x in aqueous media as a function of initial pH values, ionic strengths, and nanosheet concentrations. The pH value of the dispersion is found to change with time as a result of MXene oxidation. Specifically, MXene oxidation is accelerated in basic media by their reaction with hydroxyl anions. It is also demonstrated that oxidation kinetics are strongly dependent on nanosheet dispersion concentration, in which oxidation is accelerated for lower MXene concentrations. Ionic strength does not strongly affect MXene oxidation. The authors also report that citric acid acts as an effective antioxidant and mitigates the oxidation of both Ti 3 C 2 T x and Ti 2 CT x MXenes. Reactive molecular dynamic simulations suggest that citric acid associates with the nanosheet edge to hinder the initiation of oxidation.