2D MXene-Based Heterojunctions as Industrial Corrosion Inhibitors

Corrosion of ferrous infrastructure in aggressive industrial environments costs the global economy approximately $2.5 trillion annually. Two-dimensional (2D) MXenes have emerged as promising barrier and sacrificial inhibitors, yet their in terfacial electronic mechanisms remain poorly understood. Here we present a com prehensive first-principles density functional theory (DFT) investigation of Ti3C2Tx MXene-based heterojunctions on Fe(110), the dominant facet in carbon steel. Us ing hybrid DFT-D3(BJ) including van der Waals corrections, nudged elastic band (NEB) methods, ab initio molecular dynamics (AIMD), Bader charge analysis, and hybrid HSE06 calculations, we demonstrate that the MXene inhibitor chemisorbs preferentially at the FCC-hollow site with an adsorption energy of Eads = −2.31 eV, forming directional Fe–N and Fe–O bonds characterized by interfacial charge transfer of ∆q = 0.49 e per supercell. The minimum-energy diffusion barrier (1.14 eV) confirms kinetic trapping, while AIMD at 600 K shows no desorption, confirm ing thermal stability up to industrial service temperatures. Layer-resolved density of states reveals passivation of Fe surface states, and a computational hydrogen electrode free energy diagram shows that the inhibitor raises the activation bar rier for anodic dissolution by ∆∆G = +0.33 eV, corresponding to a predicted 4.2× reduction in corrosion current density. We validate our approach by cor relating four DFT descriptors against experimental inhibition efficiencies for 18 molecules (R2 = 0.94), establishing a predictive screening framework. Our results position MXene-based heterojunctions as a new class of high-performance, ther mally stable corrosion inhibitors and provide quantum-mechanical design rules for next-generation materials.