Theoretical Design and Simulation of Thiocarbohydrazide and its Novel Derivatives as Corrosion Inhibitors for Brass Cu–40Zn(111): A DFT, MC, and MD Study

Brass corrosion in Morocco’s coastal infrastructure is intensifed by prolonged exposure to marine environments. This study presents a theoretical design and evaluation of eight novel derivatives of thiocarbohydrazide (TCH), functionalized with phenyl and carboxyl groups to enhance electronic properties and surface interaction. The goal is to pre-screen effective corrosion inhibitors for brass (Cu–40Zn) in 3% NaCl solution, simulating seawater conditions. Density Functional Theory (DFT) was used to compute electronic descriptors including HOMO-LUMO gap, ionization energy, and global reactivity parameters. Monte Carlo (MC) simulations assessed the adsorption strength and preferred orientations on the brass surface, while Molecular Dynamics (MD) simulations evaluated the stability and behavior of inhibitor–surface interactions over time. This integrated theoretical approach enables effcient and cost-effective selection of promising candidates for future experimental validation in marine corrosion protection.