In situ quartz crystal microbalance studies of nickel hydrous oxide films in alkaline electrolytes

Yibo Mo*, Euijin Hwang, Daniel Alberto Scherson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


The microgravimetric characteristics of electrodeposited nickel and composite Ni/Co hydrous oxide films on Au electrodes in KOH electrolytes were examined in situ with a combination of quartz crystal microbalance (QCM) and voltammetric techniques. In the case of freshly prepared α-Ni(OH)2 hydrous oxide films, denoted as α-Ni(OH)2(hyd), the mass increased during oxidation and then decreased upon subsequent reduction. As the redox cycling was continued, however, this behavior gradually reversed, i.e., the mass decreased upon oxidation and then increased following further reduction. This unique effect could be correlated with a shift in the position of the oxidation peak maximum (Ep ox) in the voltammogram toward more positive potentials, which has been ascribed to the transformation of α-Ni(OH)2(hyd) into β-Ni(OH)2(hyd). Based on these findings, it can be concluded that the mechanism of ionic charge transport in these two types of lattices is markedly different. In contrast, composite Ni/Co (9:1) hydrous oxide films displayed qualitatively the same behavior as pure freshly prepared Ni(OH)2(hyd) in the same alkaline media regardless of the extent of cycling. This observation provides evidence that the incorporation of cobalt into Ni(OH)2(hyd) modifies the structural properties of the lattice during the oxidation/reduction process.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalJournal of the Electrochemical Society
Issue number1
Publication statusPublished - 1996 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry


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