Nanohybrid Self-Healing Microcapsules with NO ₂ -LDHs/ZIF-8 Shell: Synergistic Corrosion Protection and Enhanced CO ₂ Capture Capacity

Functional materials represented by NO 2 − intercalated layered double hydroxides (NO 2 -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 CO 2 capture capacity, and enhance the corrosion protection performance of the cement matrix. NO 2 -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 NO 2 -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 CO 2 capture capacities of MC, LDH/ZIF-MCs, and ZIF-MCs after 15 min were 1.634, 1.913, and 2.325 cm 3 /g, respectively. The adsorption energies of the ZIF@EC system and CO 2 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 NO 2 -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.