Adsorption of the Corrosion Inhibitor Benzotriazole on Cu(111), Zn(111), ZnCu(111) and Zn3Cu(111) Nanosurfaces

• DFT study of BTA adsorption on Cu, Zn, and Zn–Cu alloy nanosurfaces • Charge transfer direction depends on surface composition and thickness • Increasing nanosurface thickness generally strengthens BTA adsorption • Higher Zn content in alloy surfaces reduces BTA–surface interaction energy • Water models significantly alter charge transfer compared to gas phase Adsorption characteristics of benzotriazole (BTA) on Cu(111), Zn(111), ZnCu(111), and Zn₃Cu(111) nanosurfaces (NSs), including charge transfer and its direction, interaction energy, and BTA orientation on the NSs, were examined via density functional theory (DFT) calculations in both gas phase and water environment. Two different schemes were considered for describing the water environment: one considering only the electrostatic field of water (COSMO model) and other considering an explicit solvent model (COSMO model+water molecules). The influence of two parameters, the NS thickness (single-layer vs. double-layer) and the metal composition in alloy NSs, on the mentioned adsorption characteristics were systematically analyzed. For single-layer Zn(111) and ZnCu(111) NSs, charge transfer occurred from the NS to the BTA, whereas the opposite behavior was observed for the other single-layer NSs in the gas phase. The direction of charge transfer was reversed in the single-layer Zn(111) and ZnCu(111) NSs as the thickness of the NS increased and a decrease was observed for the Cu(111) NS in the gas phase. The enhancement in BTA–NS interaction energy with increasing NS thickness was observed, except for the Cu(111) NS in the gas phase. Furthermore, in alloy NSs, increasing the Zn content resulted in a decrease in BTA–NS interaction energy, except for the interaction of BTA with single-layer ZnCu and Zn 3 Cu NSs in both the gas phase and the COSMO model. It was observed that considering only of electrostatic field of water leads to a substantial change in both the magnitude and direction of charge transfer compared to the gas phase.