Synthesis of Colloidal Suspension of NiGa₂O₄ Nanoparticles through Gel-Sol Method using Organic Base

Abstract

Colloidal suspension of NiGa₂O₄ nanoparticles was synthesized by gel-sol method. Starting from an aqueous solution of Ni(NO₃)₂∙6H₂O, Ga(NO₃)₃∙nH₂O and a β-diketone ligand (acetylacetone), a precursory hydrogel was obtained through an epoxide-mediated alkalization. Then, a mild thermal treatment at 80 °C induces the deflocculation of the hydrogel, resulting in the formation of NiGa₂O₄ nanoparticles which is stably suspended in a solvent. The formation mechanism of the colloidal suspension was closely studied, revealing that chelation of acetylacetone to Ni cation with the formation of NiGa₂O₄ nanoparticles plays a key role to impart dispersion stability.