Hydrophilic Co–Pt Alloy Nanoparticles: Synthesis, Characterization, and Perspectives

Abstract

Hydrophilic Co–Pt alloy nanoparticles nearing the equiatomic ratio and dispersedin water-soluble sodium carboxymethyl cellulose were synthesized by the aqueous reduction of CoCl2⋅6H2O and [Pt(NH3)4]Cl2⋅H2O with NaBH4 in presence of the cellulosic derivative. The as-received Co–Pt nanoparticles in the cellulosic matrix possess a disordered fcc structure that, upon calcination under an Ar atmosphereand carbonization of the cellulosic mantle of the particles, transformed to an ordered fcc phase. Both as-synthesized and calcined samples are magnetically soft at room temperature and exhibit a strong magnetic response when a magnetic field is applied. On account of the chemical composition of the carboxymethyl cellulose, the coated Co–Pt nanoparticles are easily soluble in water in high concentrations and exhibit interesting ion-exchange properties.