Nitrogen–Sulfur Codoped Ti₃C₂T_<i>x</i> MXene as a Corrosion Inhibitor for Copper in a Chloride Environment: Electrochemical and Computational Studies

Abstract

MXene (Ti3C2Tx) is a highly protective layered material, but its utilization in solution medium to prevent metal corrosion has been very difficult due to surface oxidation. Thus, it was thought worthy to investigate the role of thiourea in the surface modification of MXene for the effective corrosion mitigation of copper in a chloride solution. This was carried out by the incorporation of thiourea into the MXene matrix via thermal treatment for the effective introduction of nitrogen, sulfur, and oxygen functionalities. N,S codoped Ti3C2Tx MXene was characterized using advanced analytical methods, followed by appraising the inhibition efficiency using a combined electrochemical method. Results from the electrochemical analysis revealed that increasing the concentration of N,S codoped Ti3C2Tx MXene in the chloride solution increases the inhibition efficiency up to 91% at the maximum inhibitor concentration of 100 ppm compared to pure Ti3C2Tx MXene. To support the experimental findings, inter- and intramolecular modeling via density functional theory and molecular dynamics simulation were carried out in the gas and solvation phases. As observed from the molecular modeling, N,S codoped Ti3C2Tx MXene shows a flat adsorption orientation with a good total surface coverage. The inhibition mechanism is attributed to the heteroatom doping and formation of a barrier film against the permeation of the corrosive species. This study intends to deepen the functionalization of MXenes for the benefit of corrosion science and applications in the direct solution medium of corrosive agents.