Double-layer structure, corrosion and corrosion inhibition of copper in aqueous solution

In situ STM results on the surface structure of Cu(100) electrodes in sulfuric and hydrochloric acid solution, both at potentials in the double-layer range and at the onset of anodic Cu dissolution, are presented. The Cu surface structure, morphology and dynamic behavior are found to depend strongly on the anion species and on the potential. In both electrolytes dissolution of pure Cu surfaces proceeds by a step-flow mechanism. In the presence of organic corrosion inhibitors (benzotriazole, self-assembled alkanethiolmonolayers) the otherwise dominant step-flow etching is greatly inhibited and etch pit formation is observed at more anodic potentials.