Rapid synthesis of metal-complex hydrogen-bonded framework HOF-21 with excellent chloride capture capacity for corrosion protection applications

This work investigates the novel application of a metal-complex hydrogen-bonded framework HOF-21 as an intelligent, chloride-responsive material for superior corrosion protection. A cost-effective and streamlined synthesis of HOF-21 was developed using rapid stirring at ambient conditions, offering a practical alternative to conventional static interfacial method. When embedded in epoxy coatings on copper substrates, HOF-21 significantly enhances anti-corrosion performance, outperforming traditional materials like ZnAl-LDHs. The protection mechanism is tripartite: effective chloride ion capture, reinforcement of the coating’s mechanical properties, and active protection. Experimental analyses, including kinetic and isotherm model fitting, confirm the exceptional chloride adsorption capacity, best described by pseudo-second-order and Temkin models. Molecular dynamics (MD) simulations elucidate the atomic-level mechanism, revealing that a unique hydrogen-bonded cage structure facilitates chloride sequestration. Furthermore, MD simulations demonstrate strong epoxy-HOF-21 compatibility and the formation of an interlocked structure that enhances mechanical cohesion. The active protection is attributed to the ion-exchange of fluorosilicate anions with chlorides. This work establishes M-HOFs as a versatile platform for chloride capture and provides a universal strategy for designing active-intelligent anticorrosion coatings.