Multifunctional UV Attenuation and Radical-Chain Suppression in CeO x /TiO2@MXene–Epoxy Coatings Toward Durable Corrosion Resistance

Abstract

In practical service environments, protective coatings are required to simultaneously resist the penetration of corrosive species and mitigate ultraviolet (UV)-induced degradation of polymer matrices. In this work, a multifunctional CeOx/TiO2@MXene-reinforced epoxy coating was developed to integrate UV attenuation, radical-chain suppression, and barrier protection for enhanced corrosion resistance. A silane-functionalized CeOx/TiO2@MXene (SCTM) nanofiller was fabricated through controlled hydrothermal oxidation of MXene, followed by CeOx deposition and silane grafting. The partial oxidation of MXene generated a TiO2-passivated structure while retaining the two-dimensional layered framework, thereby improving the environmental stability of the MXene-derived nanofiller. Meanwhile, low-valence Ti species on the TiO2@MXene surface promoted the formation of Ce3+-rich CeOx nanoparticles with abundant oxygen-vacancy-related surface states, providing active sites for Ce3+/Ce4+ redox cycling and radical scavenging. The CeOx/TiO2@MXene nanocomposite displayed broadened optical absorption and enhanced UV attenuation behavior. After 100 h of xenon-lamp aging, the SCTM/EP composite coating maintained superior mechanical integrity and corrosion resistance. Electrochemical impedance spectroscopy (EIS) results revealed that, after UV aging followed by 100 d of immersion in 3.5 wt % NaCl solution, SCTM/EP maintained an impedance modulus (|Z|0.01 Hz) of 6.58 × 109 Ω·cm2, representing a two-order-of-magnitude improvement over pure epoxy (8.09 × 107 Ω·cm2). The enhanced durability is attributed to the integrated effects of UV attenuation, Ce3+/Ce4+-mediated radical scavenging, and retention of coating barrier properties, which collectively suppress UV-induced photo-oxidative degradation and delay the ingress of corrosive species. This study provides an effective strategy for enhancing the UV-aging and corrosion protection resistance of epoxy coatings through multifunctional MXene-derived nanocomposites.