Colloidal synthesis of CoAl2O4 nanoparticles using dodecylamine and their structural characterization

Abstract

According to the LaMer mechanism, if the concentration of the reagents in the colloidal solution is increased gradually, then this can reach the supersaturating limit. The formation of the nanoparticles was explained by the presence of the dodecylamine organic molecules within the solution, which saturated the nanocrystal surfaces that inhibited the growth of the particles generating a rapid nucleation process. A non-aqueous colloidal method was formulated using the organic compound dodecylamine as a surfactant agent. By the systematic variation of dodecylamine concentration the supersaturating limit was controlled, allowing obtain two distinct morphologies for the CoAl2O4 spinel phase. The thermal decomposition of the precursor mixture resulted in the formation of the blue CoAl2O4 spinel phase at a temperature of 800°C.