Delamination of surfactant-intercalated brucite-like hydroxy salts of cobalt and copper and solvothermal decomposition of the resultant colloidal dispersions

Abstract

Surfactant anion intercalated hydroxy salts of copper and cobalt of the formula M(OH)_2−x(surf)_x·mH₂O [M = Cu, Co; surf = dodecyl sulfate, dodecyl benzene sulfonate, and x = 0.5 for Cu and 0.67 for Co] delaminate readily in 1-butanol to give translucent colloidal dispersions that are stable for months. The extent of delamination and the colloidal dispersion observed in these solids is higher than what had been observed for layered double hydroxides. The dispersions yield the corresponding nanoparticulate oxides on solvothermal decomposition. While the copper hydroxy salt forms ∼300 nm dendrimer-like CuO nanostructures comprising nanorods of ∼10 nm diameter, the cobalt analogue forms ∼20 nm superparamagnetic particles of Co₃O₄.