Functionalized metal–organic frameworks for sustainable corrosion protection of carbon steel: interfacial chemistry and mechanistic insights

Abstract

The present study investigates the corrosion inhibition performance of a Cu–metal–organic framework (Cu–MOF) functionalized with bay leaf-derived carbon dots (MOF@CDs) for Q235B steel in 1 M HCl solution. The electrochemical tests (open circuit potential, potentiodynamic polarization curves, and electrochemical impedance spectroscopy) results demonstrated that the MOF@CDs could effectively inhibit steel corrosion, characterized by shifting the corrosion potential in the negative direction and decreasing the corrosion current density with the increase of the inhibitor concentration. The MOF@CDs function as an effective mixed-type corrosion inhibitor, primarily suppressing the anodic dissolution process while also hindering cathodic hydrogen evolution. Surface characterization using Fourier transform infrared spectroscopy (FTIR) confirmed the adsorption of MOF@CDs onto the steel surface through interactions involving hydroxyl, carboxyl, and aromatic groups. UV-vis spectroscopy further confirmed the adsorption behavior of MOF@CDs on the steel surface by suggesting the complexation between the metal and inhibitor. The presence of bay leaf-derived CD components in the MOF structure enhanced its corrosion inhibition capability, as the polyphenolic and oxygen-rich constituents facilitated strong surface interactions. Additionally, atomic force microscopy (AFM) demonstrated a substantial reduction in surface roughness after inhibitor adsorption, highlighting the protective barrier formation.