Experimental and computational study of aromatic ring effects on corrosion inhibition in the H2S media

In this work, four quaternary ammonium salts (QAS) were synthesized and applied as corrosion inhibitors for carbon steel (CS) in the H2S media, with different concentrations at 293 and 333 K. The performance and mechanism of QAS inhibitors were studied by electrochemical techniques (OCP, PDP, EIS, and PZC), weight loss (WL), and surface topography methods (SKP, AFM, SEM/EDS, and contact angle). Moreover, computational investigations (DFT and MD) were carried out to clarify the inhibition mechanism of inhibitors. The QASs act as mixed-type inhibitors with a maximum inhibition efficiency of up to 98.5 % in 100 mg L-1. Surface analysis well supported the experimental data. Furthermore, the computational results showed that QASs have comparatively high adsorption energy on the CS, which agrees with the experimental data.