Corrosion inhibition of a novel antihistamine-based compound for mild steel in hydrochloric acid solution: experimental and computational studies

Focused on the assessment of the diphenhydramine hydrochloride (DPH) capabilities as an alternative to conventional and harmful industrial corrosion inhibitors, electrochemical techniques were employed. The optimum concentration of 1000 ppm was determined by molecular simulation and validated through electrochemical experiments. The results acquired from the electrochemical impedance spectroscopy (EIS) study showed that DPH at a concentration of 1000 ppm has a corrosion efficiency of 91.43% after 6 h immersion. The DPH molecules' orientation on the surface was assessed based on EIS predicting horizontal adsorption on the surface. Molecular simulations were done to explore the adsorption mechanism of DPH. The DPH molecules' orientation on the surface was also assessed based on computational studies confirming the horizontal adsorption predicted by EIS.