Transition from chemisorbed copper layers to bulk deposits on platinized platinum in sulfuric acid solution

Abstract

Thin copper films which do not yet possess the properties of bulk deposits are formed on platinized platinum in 0.5 M H 2SO 4 + 0.01 M CuSO 4 · 5H 2O within a narrow potential range of about 30 mV positive to the equilibrium potential of the net reaction Cu 2+ + 2e − = Cu and at shorter times in the potential range of about 10 mV negative to it. In the latter case the presence of this film and of a monolayer of Cu ad is still visible in anodic stripping curves at constant current. Bulk deposits are non-uniform as evidenced by the appearance of reddish patches. The behavior of bulk deposits is approached by the copper films when the ratio of the anodic stripping charge to the charge for the anodic removal of a monolayer of H ad becomes larger than 10.