Isoindigo derivatives as some potential corrosion inhibitors for mild steel in hydrochloric acid solution: synthesis, experimental and theoretical studies

This investigation synthesized two isoindigo derivatives (IIDBr-NBr and IIDBr-MBr). These derivatives were then applied as green corrosion inhibitors for mild steel in a 1mol·L−1 HCl aqueous solution. The study investigated the corrosion inhibition performance of IIDBr-NBr and IIDBr-MBr through electrochemical and weight loss (WL) measurements, as well as surface analysis (SEM, AFM and XPS). The results showed that both IIDBr-NBr and IIDBr-MBr exhibited excellent corrosion inhibition performance (inhibition efficiency of 96.27% for IIDBr-NBr and 96.46% for IIDBr-MBr). Quantum chemical calculations based on density functional theory (DFT) and molecular dynamics (MD) were used to reveal the adsorption mechanisms of IIDBr-NBr and IIDBr-MBr at the steel/solution interface.