Corrosion Inhibition Effect of Quinoxaline Derivative on Carbon Steel in Hydrochloric Acid: Experimental and Theoretical Investigations

The inhibitory effect of ethyl 2-(2-oxo-3-phenylquinoxalin-1(2H)-yl) acetate (PQXA) on the corrosion of carbon steel (CS35) in a 1 M HCl electrolyte was investigated using weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), surface morphology, and UV–visible spectroscopy techniques. Quantum chemical calculations were also conducted to corroborate the experimental findings. The experimental results indicate that PQXA has excellent effectiveness in inhibiting the corrosion of CS35 in 1 M HCl. The inhibition efficiency demonstrated improvement with increasing concentration, reaching a maximum of 94.7