Nanohybrid Self-Healing Microcapsules with NO₂-LDHs/ZIF-8 Shell: Synergistic Corrosion Protection and Enhanced CO₂...

Functional materials represented by ${\mathrm{NO}}_2^{-}$ intercalated layered double hydroxides (NO₂-LDHs), zeolitic imidazolate frameworks-8 (ZIF-8), and self-healing microcapsules have demonstrated significant potential in improving the performance of cement-based materials, which are employed to promote cement hydration, enable microcrack self-healing, improve CO₂ capture capacity, and enhance the corrosion protection performance of the cement matrix. NO₂-LDHs and ZIF-8 were utilized in nanohybrid self-healing microcapsules. The experimental findings revealed that the sample exhibited excellent dispersibility, and the shell size of a typical microcapsule is about 5.26 μm. The initial structure of NO₂-LDHs was preserved during the encapsulation process, and the anionic species of LDHs within the microcapsule shell underwent ion exchange with Cl^-. At 25 °C, the CO₂ capture capacities of MC, LDH/ZIF-MCs, and ZIF-MCs after 15 min were 1.634, 1.913, and 2.325 cm³/g, respectively. The adsorption energies of the ZIF@EC system and CO₂ at 0.1 and 1.0 GPa were -0.360 and -0.599 eV, respectively. The nanohybrid microcapsules demonstrate a unique force/Cl^- synergistic triggering mechanism, and the environmental adaptability of the self-healing system is significantly enhanced by the dual response mechanism. At a corrosion duration of 9 days, the protection efficiencies of MCs and LDH/ZIF-MCs were 90.32% and 98.82%, respectively. The corrosion protection performance is synergistically achieved through the self-healing of the core material, the ion effect of NO₂-LDHs and the molecular effect of nanomaterials. The study provides a novel approach for the development of sustainable materials suitable for chlorine and carbon synergistic corrosion environments.