Ab initio exploration of modified carbon nanotubes as potential corrosion inhibitors

In order to develop novel unexplored potential corrosion inhibitors, covalently modified single-walled carbon nanotubes (SWCNT) via benzoic (–PhCOOH) and aniline (–PhNH2) groups are being investigated as corrosion inhibitors for the first time. Utilizing a comprehensive approach, this study employed density functional theory (DFT), Monte Carlo (MC), and molecular dynamics simulations (MD) to assess the adsorption behavior of modified nanotubes as corrosion inhibitors on the Cu(111) surface within a simulated aqueous HCl corrosion medium. The results provided molecular information on the adsorption capability, geometry adsorption centers, and adsorption energies (Eads) of carbon nanotubes on the surface of Cu(111). The adsorption energy values unveiled robust interactions between SWCNT–PhCOOH and SWCNT–PhNH2 inhibitors and the Cu(111) surface, suggesting a highly effective corrosion protection mechanism. The calculated Eads values exhibited notable ranges, spanning from –260.82 to –308.18 kcal/mol for SWCNT–PhCOOH and –220.92 to –261.01 kcal/mol for SWCNT–PhNH2 with the maximum probability values, representing the most favorable adsorption scenarios, determined to be –292.96 and –229.39 kcal/mol, respectively. A key insight from Monte Carlo simulations underscored the inherent spontaneity of the adsorption process, corroborated by the consistently negative Eads values. These findings collectively underscore the substantial affinity of the inhibitors to the copper surface, contributing to a deeper comprehension of their corrosion inhibition capabilities.