Multiscale computational modeling of phytochemicals for iron corrosion inhibition: Bridging DFT, SCC-DFTB, and molecular dynamics for eco-friendly solutions

Investigating environmentally benign corrosion inhibitors is crucial for addressing the widespread issue of material deterioration. This research conducts a detailed computational evaluation of four phytochemicals − Taraxasterol (TTL), Chicoric acid (CHA), Tetrahydroridentin B (THR), and Caffeic acid (CFA) − for their potential in acting as sustainable inhibitors against iron surface corrosion. Utilizing Density Functional Theory (DFT) with B3LYP functional, self-consistent-charge density-functional tight-binding (SCC-DFTB), and molecular dynamics (MD) simulations, this study thoroughly examines both the global and local chemical reactivities, as well as the bonding interactions of these compounds with the Fe(1 1 0) surface. The findings reveal that CHA and CFA demonstrate remarkable adsorption properties, as demonstrated by their electronic features and bonding characteristics. Notably, Fukui function analyses identify multiple active sites in CHA and CFA, enhancing electron transfer and coordination with the metal surface. SCC-DFTB simulations show the formation of covalent linkages between these phytochemicals and iron atoms, resulting in their parallel arrangement on the Fe(1 1 0) surface, a finding supported by MD simulations. This research underscores the potential of CHA and CFA as corrosion inhibitors and provides a nuanced understanding of their molecular interactions, paving the way for further exploration and application in eco-friendly corrosion prevention.