Oxide layers developed on copper electrodes in Cu(II) solutions containing ligands

On the origin of the spontaneous potential oscillations observed during galvanostatic deposition of layers of Cu and Cu2O in alkaline citrate solutions

“…5a, this gives a copper deposition current efficiency of only 88%. This suggests that some Cu(I) is lost into the solution in accordance with previous ring-disk findings [24][25][26][27][28].…”

“…9 verify that the reduction of Cu 2 O gives rise to the mass loss expected for a complete reduction of the Cu 2 O deposit. The reduction of Cu 2 O, which also has been studied by Survila and co-workers [28,31], can likewise be performed galvanostatically. In the latter case, a gradual mass decrease was observed as the potential dropped from approximately À0.6 to À0.8 V, employing a current density of À1.0 mA/cm 2 .…”

“…This is most likely caused by electroless deposition of Cu 2 O due to a combination of comproportionation [27], according to reaction (4) (4) are likely to occur under the present experimental conditions. While it is well-known [24][25][26][27][28] that Cu(I) is formed as an intermediate during copper deposition from solutions containing Cu 2+ or Cu(II)-complexes (including Cu(II)-citrate complexes [24]), the stability of Cu(I) is generally low due to the fact that Cu(I) is rapidly reduced to copper at the potentials needed to reduce Cu 2+ in the absence of a ligand stabilising the Cu(I) oxidation state. In the present case, Cu 2 O is likely to be the predominating Cu(I) species in the solution since there is no evidence for the (unlikely) formation of a Cu(I)-citrate complex.…”

Kinetics of Sn(II) reduction in acid sulphate solutions containing gluconic acid

“…4, pH 5) that show a quite good reproducibility. Similar current peaks were also observed in the case of copper electrodes containing surface oxides [47]. Besides, some deviations from linearity can be distinguished in data obtained at pH 5 (Fig.…”

Effect of tartaric acid in the electrodeposition of zinc

“…The discharge of H + ions from protonated organic ligand species on metallic electrodeposited layers has been described previously [19][20][21]. The reduction peak II r is correlated with the reduction of the total bulk Zn(II) ion also via the dissociation of growth processes have also been observed and sometimes transitions from one to another have been reported.…”