Article ID Journal Published Year Pages File Type
187051 Electrochimica Acta 2013 7 Pages PDF
Abstract

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. The first widely accepted route corresponds to ZnO precipitation from Zn2+ and OH− produced by NO3− reduction; the second route, which is discussed in this article, is due to Zn2+ reduction into metallic Zn followed by its oxidation by nitrate ions. For this case, we demonstrate why Zn formation cannot be observed while Zn2+ reduction was detected. Structure and morphology of bulk deposits were investigated using X-ray diffraction and scanning electron microscopy. Thin films of well-oriented ZnO nanorods 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 grow along the (0 0 2) direction.

► A new mechanism for ZnO formation on vitreous carbon is proposed in nitrate medium. ► At low potential, a ZnO layer is obtained by direct oxidation of bulk zinc by nitrate ions. ► At higher cathodic potential, ZnO is obtained by two parallel mechanisms. ► The nanostructured film obtained at −1.1 V has a (0 0 2) texturation.

Related Topics
Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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