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Surface Behavior of Nickel Powders in Aqueous Suspensions

2005; American Chemical Society; Volume: 109; Issue: 10 Linguagem: Inglês

10.1021/jp0448954

1520-6106

Nicolás Hernández, Rodrigo Moreno, A.J. Sánchez‐Herencia, J.L.G. Fierro,

Electrochemical Analysis and Applications

The colloidal behavior of nickel aqueous suspensions is studied and compared to that of NiO suspensions. Under acidic conditions, nickel readily dissolves, but no dissolution takes place at basic pH. Zeta potential is studied as a function of pH, showing that the isoelectric point (IEP) occurs at pH 3.5-4. Above the IEP there is a zeta potential plateau, which is associated to the predominance of NiO(OH) species. At pH 9 a new decrease in zeta potential is associated to NiO predominance. XPS studies support that suspensions prepared at pH >9 lead to NiO-enriched species, while suspensions prepared at lower pH form NiO(OH) species.