2-Mercaptobenzimidazole as a copper corrosion inhibitor: Part II. Surface analysis using X-ray photoelectron spectroscopy

Highlights: •2-Mercaptobenzimidazole bonds to the Cu surface via N and S atoms. •No cupric species were formed on the copper surface. •Chlorine was not involved, whereas water molecules were involved in the surface layer. •The thickness of the 2-mercaptobenzimidazole surface layer is 1.9 ± 0.5 nm. •Tentative orientations of 2-mercaptobenzimidazole on Cu substrate are presented. -- Abstract: In Part I of this study, the high corrosion inhibition effectiveness of 2-mercaptobenzimidazole (MBIH) in 3 wt.% NaCl solution was unambiguously proven. In Part II, using angle-resolved X-ray photoelectron spectroscopy (XPS), the surface chemical structure and composition of adsorbed MBIH on Cu from the same solution was investigated. It was found that MBIH molecules are directed toward the Cu surface through their N and S atoms. The MBIH layer thickness is 1.9 ± 0.5 nm, as determined from a detailed analysis of the background in the XPS spectra. Tentative MBIH orientations on Cu were suggested based on the XPS measurements