Exfoliation of α-hydroxides of nickel and cobalt in water

p-Aminobenzoate ion intercalated α-hydroxides of nickel/cobalt were synthesized by precipitation using ammonia (pH = ∼12). Aqueous colloidal suspension of α-hydroxide of nickel/cobalt was obtained on washing the precipitate as the pH was reduced to ∼7. The development of partial positive charge on the amine end of the intercalated anion causes repulsion between the layers leading to exfoliation and colloidal suspension of monolayers in water. While the layers could be restacked from the colloidal suspension in the presence of other anions in the case of α-cobalt hydroxide, the exfoliation could not be reversed easily in the case of the nickel analog.

p-Aminobenzote intercalated α-hydroxides of nickel and cobalt exfoliate in water when the pH of the medium is ∼7.Figure optionsDownload high-quality image (30 K)Download as PowerPoint slide