Structure and electrocompression of chloride adlayers on Cu(111)

The specific adsorption of chloride on Cu(111) from acidic aqueous electrolyte (pH 3) was investigated by in-situ surface X-ray diffraction, revealing an incommensurate hexagonal rotated adlayer. The structure and its potential dependence suggest a strong adsorbate–adsorbate interaction as compared to other halide adlayers on (111)-oriented metal electrode surfaces. The orientational epitaxy can be rationalized by the model suggested by Grey and Bohr (Europhys. Lett. 18, 171, 1992), which is based on symmetry considerations.