Computational Insights Into Corrosion Inhibition Mechanism: Dissociation of Imidazole on Iron Surface.

Corrosion inhibitors are widely used to mitigate safety risks and economic losses in engineering, yet post-adsorption processes remain underexplored. In this study, we employed density functional theory calculations with a periodic model to investigate the dissociation mechanisms of imidazole on the Fe(100) surface. Imidazole was found to adsorb optimally in a parallel orientation, with an adsorption energy of -0.88 eV. We explored two dissociation pathways: CH and NH bond cleavages and found CH dissociation having a lower activation barrier of 0.46 eV. Intriguingly, an alternative indirect route CH dissociation pathway involving a tilted intermediate state was found to be competitive. Both indirect and direct CH dissociation pathways are energetically more favorable than NH cleavage. Molecular dynamics simulations reveal that indirect CH dissociation occurs rapidly. This study proposes an alternative protective mechanism involving dissociated imidazole inhibitors, offering new insights for corrosion inhibitor design.