In this research, the effects of fresh and oxidized MXene on the surface, adhesion, and corrosion-resistant properties of waterborne epoxy coatings are considered. The oxidized MXene is prepared through storage of fresh MXene nanosheets in an open vial for 1 month. The results confirm that the waterborne epoxy coating loaded with silane functionalized fresh MXene nanosheets (epoxy/F-MXene) has significantly higher barrier performance and anti-corrosion behavior than the sample modified with silane functionalized oxidized MXene nanosheets (epoxy/F-O-MXene). Indeed, the F-MXene nanosheets (with defect-free and large two dimensional morphology) are able to effectively inhibit the path of corrosive media as well as increment the epoxy matrix compactness compared to the F-O-MXene (with broken nanosheet morphology composed of TiO 2 nanoparticles) due to rapid oxidation of the MXene nanosheets in the environment. Besides, the epoxy/F-MXene nanocomposite coating has slightly higher water contact angle and adhesion strength to the metallic substrate compared to the epoxy/F-O-MXene. The results of this research clearly reveal the importance of preventing MXene oxidation before application as nanofiller in the polymer coatings.
A novel oxidized MXene-supported MCo2O4 (oxidized MXene/MCo2O4, M = Mn, Zn, Cu and Co) nanocomposite was successfully synthesized through a facile hydrothermal assisted calcination method. Various characterization results indicated that MCo2O4 nanoparticles were successfully formed in situ on MXene nanosheets, which effectively reduce the aggregation of nanoparticles and remarkably improve the specific surface area, especially MZC (203.5 m2 g−1). Among the oxidized MXene/MCo2O4 nanocomposites, oxidized MXene/ZnCo2O4 (MZC) enormously ameliorated the performance of AP decomposition. With adding MZC (2.0 wt%), the high-temperature decomposition (HTD) temperature of AP could significantly decrease to 297.1 °C, while the decomposition heat could increase to 1409.6 J g−1, respectively. The apparent activation energy of AP decomposition decreased from 209.6 kJ mol−1 (pure AP) to 104.5 kJ mol−1 (AP mixed with MZC). The excellent catalytic performance of MZC might be due to the synergistic effect of MXene nanosheets and ZnCo2O4 nanoparticles. It could be foreseen that MZC would be an excellent material for optimizing AP decomposition and would supply an idea for the development of new catalyst materials.