Tomato leaf waste extract as corrosion inhibitor for copper–nickel alloy in H2SO4 medium

Abstract The tomato leaf waste extract (TLWE) was obtained through a decoction process and its effectiveness as a corrosion inhibitor on a copper–nickel alloy in sulfuric acid was assessed. Electrochemical measurements demonstrated that the extract functions as a mixed inhibition agent, effectively controlling both anodic and cathodic reactions, achieving an inhibition efficiency greater than 95% at 400 mg/L. Surface characterization using SEM and AFM further confirmed the protective role of the extract, revealing a markedly smoother alloy surface and substantially reduced corrosion damage compared to the uninhibited system. Additionally, integrating quantum chemical computations with molecular dynamics simulations, the study demonstrates the remarkable corrosion-inhibition efficiency exhibited by the active constituents of TLWE. The conformity of TLWE adsorption on copper surfaces to the Langmuir monolayer model, as demonstrated by adsorption isotherm model, indicates concurrent physisorption and chemisorption mechanisms.