High water and oxygen reactivity inducing excellent anti-corrosive performance in waterborne Ti2CTx/epoxy composite coating

• The high water and oxygen reactivity of Ti 2 CT x was used to improve anti-corrosion properties of epoxy coating. • The Ti 2 CT x was successfully add into the composite coating and performed excellent anti-corrosive properties. • The water and oxygen were adsorbed and consumed by the surfaces and edges of Ti 2 CT x in the coating. • The product TiO 2 acted as a blockage to the diffusion path of the corrosive medium. The water and oxygen reactivity of MXene is one of its intrinsic characteristics, which is very detrimental in the areas including electromagnetic shielding, sensors, supercapacitors, etc. However, it plays an active role in anticorrosive coatings. In this work, few layer Ti 2 CT x obtained via LiF+HCl etching and ultrasonic treatment were added into waterborne epoxy coating through liquid phase blending method. They were found distributing in the coating evenly and stably. The EIS tests showed that the coating with 1.0 wt.% Ti 2 CT x content could maintain an impedance modulus value of 10 8 after 21 days of immersion, which is over 2 orders of magnitude higher than that of the pure epoxy coating. The adsorption interaction effects of Ti 2 CT x (including the surfaces and edges) on water and oxygen were further investigated by DFT calculations. The distribution of oxidation products TiO 2 in the coating were also investigated through experimental observations to analyze their corrosion protection mechanism. This study has important implications for the potential application of highly water and oxygen reactive MXene in the field of anti-corrosive coatings.