New insight into the mechanism of cathodic electrodeposition of zinc oxide thin films onto vitreous carbon

N. Ait Ahmed (1) , M. Eyraud (2) , H. Hammache (3) , F. Vacandio (2) , S. Sam (3) , N. Gabouze (4) , P. Knauth (2) , K. Pelzer (2) , T. Djenizian (2)

1 LECVE - Laboratoire d'Electrochimie, Corrosion et de Valorisation Energétique [Université de Béjaïa]
2 MADIREL - Matériaux divisés, interfaces, réactivité, électrochimie
3 Université Abderrahmane Mira [Béjaïa]
4 UDTS - Unité de Développement de la Technologie du Silicium

In this study, the mechanism of zinc oxide (ZnO) electrodeposition from aqueous zinc nitrate solution at 70°C was investigated on vitreous carbon and bulk zinc electrodes using cyclic voltammetry experiments. Mechanisms are presented for the ZnO formation: the first widely accepted route corresponds to ZnO precipitation from Zn 2+ and OH-produced by NO3-reduction; the second route, which is discussed in this article, is due to Zn 2+ reduction into metallic Zn followed by its oxidation by nitrate ions. For this case, we demonstrate why Zn formation can not be observed while Zn 2+ reduction was detected. Structural and morphological of bulk deposits were investigated using X-ray diffraction and scanning electron microscopy. Well-oriented ZnO nanorods forming thin films were grown on vitreous carbon from Zn(NO3)2 solution at low cathodic potential corresponding to that of zinc metal deposition. X-ray diffraction (XRD) measurements showed that the nanorods are crystalline and preferably grown along the (002) direction.

Keywords: cyclic voltametry; ZnO deposition mechanism; nanowires; nitrate solutions

Domains: Chemical Sciences; Material chemistry

N. Ait Ahmed, M. Eyraud, H. Hammache, F. Vacandio, S. Sam, et al.. New insight into the mechanism of cathodic electrodeposition of zinc oxide thin films onto vitreous carbon. Electrochimica Acta, 2014, 94, pp.238 - 244. ⟨10.1016/j.electacta.2013.01.103⟩. ⟨hal-01465928⟩