The first X-ray photoelectron spectroscopy surface analysis of 4-methyl-2-phenyl-imidazole adsorbed on copper
This article focuses on a detailed surface analytical study by X-ray photoelectron spectroscopy (XPS) of 4-methyl-2-phenyl-imidazole (MePhI) adsorbed from 3 wt% NaCl solution on a Cu surface. It is shown for the first time that MePhI is a Cu corrosion inhibitor in chloride solution after short-term (1–100 h) and long-term immersion periods (180 days), and that MePhI is an anodic-type corrosion inhibitor. Surface analysis was first performed by examination of the Cu surface layer chemical structure, followed by the analysis of the surface layer thickness according to the Tougaard method. It is shown that a very thin layer is formed. Next, a detailed angle-resolved XPS analysis was performed to study the manner of MePhI bonding on the copper surface. It is claimed that the MePhI molecule connects to the surface via C and N atoms. A flat orientation of MePhI molecules, parallel to the copper surface, is suggested.