The Effect of Surface Geometry of Copper on Dehydrogenation of Benzotriazole. Part II

Abstract

Dehydrogenation of benzotriazole (BTAH)—an outstanding corrosion inhibitor for copper—on low Miller index surfaces of copper and under-coordinated defects thereon has been characterized using density functional theory calculations. The issue of dehydrogenation is of importance, because benzotriazole bonds strongly to copper surfaces—a requirement for successful competition with corrosive species—only in dehydrogenated (or deprotonated) form. The calculated dehydrogenation activation energy of weakly chemisorbed BTAH—oriented with the molecular plane perpendicular to the surface—is about 1.1 eV on Cu(111), whereas, on more open Cu(100) and step-edges, the activation energy decreases to values closely below 1.0 eV. On the other hand, dehydrogenation activation energies of physisorbed BTAH—oriented with the molecular plane parallel to the surface—are found to be considerably smaller; the smallest calculated value is 0.73 eV. We also find that dehydrogenation barriers decrease with increasing molecular covera...