Multifunctional ZnAl-MoO4 LDH assembled Ti3C2Tx MXene composite for active/passive corrosion protection behavior of epoxy coatings

The active–passive protective dual-functional and acid-response ZnAl-MoO4 LDH@Ti3C2Tx MXene composite corrosion inhibitor can endow the efficient anticorrosion and certain self-healing property of epoxy coating (MoO42- release rate related with external pH value) for Q235 steel, owing to the synergistic effect including the physical shielding effect of two-dimensional Ti3C2Tx MXene, Cl- adsorption/capture effect of hydrotalcite, and inhibition membrane formation of Zn2+ and MoO42- in the composite corrosion inhibitor. [Display omitted] •Active/passive protective ZnAl-MoO4 LDH@Ti3C2Tx MXene was prepared firstly.•Novel corrosion inhibitor can combine physical barrier and response inhibition.•Composite coating exhibits the good anticorrosion/certain self-healing property. Two-dimensional Ti3C2Tx MXene is a promising anticorrosive filler for epoxy coating, but only passive protection makes Ti3C2Tx-based composite coating unable to meet long-term anticorrosive requirements. For this reason, the ZnAl-NO3 LDH layers and active corrosion inhibitor MoO42- are introduced into Ti3C2Tx MXene surface, where LDH layers cannot only be used as the acid response nanocontainer for MoO42-, but also an additional active corrosion inhibitor, and a reservoir to trap Cl-. The obtained ZnAl-MoO4 LDH@Ti3C2Tx MXene composite corrosion inhibitor is an acid-response and active/passive protective dual-functional composite corrosion inhibitor. The ZnAl-MoO4 LDH@Ti3C2Tx MXene contained composite coating can exhibit the excellent anticorrosion performance and certain self-healing property, owing to the synergistic effect including the physical shielding effect of two-dimensional Ti3C2Tx MXene, Cl- adsorption/capture effect of hydrotalcite, and inhibition membrane formation of Zn2+ and MoO42- in the composite corrosion inhibitor. This work is of great significance to the synthesis of multifunctional composite corrosion inhibitors and the application of Ti3C2Tx MXene-based composite coatings in the field of corrosion protection.