Cerium cations orchestrated high-aspect-ratio covalent organic frameworks for synergistic corrosion and wear protection

Simultaneously enhancing the corrosion resistance and mechanical durability of epoxy (EP) coatings remains a substantial challenge for long-term safe-guarding of metallic structures in aggressive environments. Covalent organic frameworks (COFs) have emerged as promising protective nanofillers, but their applications predominantly rely on physical barrier effects, leaving the potential of their functional pore channels for metal-ion coordination largely unexploited. Herein, inspired by the intrinsic metal-ion adsorption capability of COFs, we reversely harnessed their functional pore channels to immobilize cerium cations through a pore-confinement and coordination strategy. This approach led to the construction of rare-earth functionalized COFs, namely spherical Ce@TATP and high-aspect-ratio Ce@TADM, which integrate both passive and active protection functions. The high-aspect-ratio TADM, owing to its highly ordered pore channels and abundant nitrogen/oxygen-rich coordination sites, enabled efficient cerium anchoring. The synergistic integration of the high-aspect-ratio TADM barriers and pH-responsive cerium inhibition effectively impeded the transport of corrosive species. The resulting coating exhibited a charge-transfer resistance of 1.29 × 10 7 Ω·cm 2 and a corrosion protection efficiency of 88.5% after 4 weeks of immersion in 3.5 wt% NaCl solution. More importantly, cerium coordination achieves mechanical reinforcement of the composite coating and improves its load-bearing capability and resistance to plastic deformation, as evidenced by the H 3 / E r 2 value rising by 23.3% and 43.0% compared with TADM/EP and pure EP, respectively. Combined with the layered nanoarchitecture of TADM, such coating reinforcement lowers the wear rate by 65.04% relative to pure EP. This work establishes the structure-property relationship linking COF nanoarchitectures, cerium incorporation and multifunctional protective performance, providing a novel strategy to construct advanced anti-corrosion and anti-wear coatings.