Performance and theoretical study on corrosion inhibition of 2-(4-pyridyl)-benzimidazole for mild steel in hydrochloric acid

Inhibition performance of 2-(4-pyridyl)-benzimidazole (PBI) against corrosion of mild steel in 1.0 M HCl was investigated by weight loss and electrochemical measurements. The inhibition efficiency increased with increasing inhibitor’s concentration, but decreased with the increase in temperature and concentration of the acid. The theoretical results from DFT and MD simulations reveal that adsorption of PBI depends on the formation of coordinative bonds between PBI molecule and iron surface, and the binding energy between PBI molecule and iron surface is the highest among the three studied compounds.

► Excellent inhibition efficiency of 2-(4-pyridinyl)-benzimidazole (PBI).
► Effects of temperature and concentration of acidic media.
► Active sites and capability of adsorption.
► Nearby flat orientation of PBI on iron surface and highest interaction energy.