New and Green Corrosion Inhibitor Based on New Imidazole Derivate for Carbon Steel in 1 M Hcl Medium: Experimental and Theoretical Analyses

In this research work, a new and green corrosion inhibitor based on new imidazole derivate (IMD) was introduced for carbon steel in 1 M HCl medium. Its inhibition properties were fully characterised by the gravimetric, electrochemical, surface and quantum chemical analyses. The experimental results confirmed that the inhibition efficiency of IMD was over 99% at 150 mg/L, forming a protective hydrophobic film on the metal surface, which maximally blocked the cathodic and anodic corrosive processes by adsorption. The electrochemical results suggested that the IMD is a mixed-type inhibitor. The adsorption behaviour of IMD was obeyed by Langmuir isotherms. The gravimetric results show that the inhibition efficiency depends on the change of concentration and temperature. The experimental tests were supported by the DFT (density functional theory) measurements, and a good relationship was found among these tests. The observed results of the surface analysis indicated that the metal surface was seriously improved with the presence of IMD.

Tailoring graphene-supported Ru nanoparticles by functionalization with pyrene-tagged N-heterocyclic carbenes

The catalytic properties of graphene-supported ruthenium nanoparticles (Ru@rGO) have been finely tuned by modifying their metal surface with pyrene-tagged N-heterocyclic-carbene ligands (pyr-IMes). The nature and interaction modes of the pyr-IMes...

Atomic Scale Insight into Corrosion Inhibition: DFT Study of 2-Mercaptobenzimidazole on Locally De-Passivated Copper Surfaces

A key factor for effective inhibition by organic molecules of the initiation of localized corrosion by pitting is their ability to form a protective organic film in locally de-passivated zones exposing the bare metal next to the oxide-covered surface. Herein, based on quantum chemical DFT calculations, we study the chemistry of the interface between 2-mercaptobenzimidazole (MBI) and a copper surface partially covered by a Cu2O passive oxide film. The results show the adaptability of the molecule to adsorb strongly on the different zones, oxide or metal, of a locally de-passivated surface. However, differences in the local adsorption configurations, involving covalent bonding with H-bonding depending on oxide or metal and on conformer, thione or thiolate, lead to the formation of an inhomogeneous organic film. Increasing order of local adsorption strength is oxide walls < metal surface < oxide surface < oxide edges for the thione species, whereas there is no significant difference of local adsorption strength for the thiolate species. Our results suggest that both species of MBI can heal the oxygen and copper low coordinated sites as well as can protect the exposed metal surface, thus enhancing the barrier properties of the passivated surface even when locally defective.