Study On Controllable Preparation Of Monodisperse Magnetic Nanoparticles Using Metal Carbonate Precursor

Magnetic nanoparticles have shown appealing features in biomedical applications due to their unique physical and chemical properties.The controllable preparation of magnetic nanoparticles with high quality is the fundamental premise.Thermal decomposition in high boiling point solvents has been demonstrated to be the most effective approach.The metal precursors reported in past decades suffered from the high-price,environment unfriendly,high toxicity,or the low metal atomic efficiency in the solvent thermal decomposition.Metal carbonate precursors not only have advantages of easily available,environment-friendly,high metal efficiency,but also had been used for solid thermal decomposition.In this desert,we firstly employed ferrous carbonate as a model compound for the preparation of Fe₃O₄nanoparticles by solvent thermal decomposition and investigate the influence of reaction condition.Besides,more metal carbonate precursors such as manganese carbonate,zinc carbonate,cobalt carbonate,and basic nickel carbonate,were also employed to synthesize their ferrite nanoparticles.The detailed results are shown in the following:(1)Synthesis and characterization of ferrous carbonate crystals:Ferrous carbonate precursor was successfully prepared using co-precipitation with ferrous sulfate heptahydrate and sodium carbonate and characterized with XRD and TGA to study the crystalline and thermochemical properties.The decompose temperature between 150-330? made FeCO₃ a good candidate for thermal decomposition precursor.(2)Controllable synthesis of monodisperse Fe₃O₄ nanoparticles:The FeCO₃ precursor was firstly used to synthesize monodisperse superparamagnetic Fe₃O₄ nanoparticles,and then the reaction condition of the amount of oleic acid,aging time,aging temperature,and amount of precursor were investigated for the influence on magnetic particle size.The aging temperature and amount of precursor showed significant effect on the particle size,while the amount of oleic acid and aging time had not obviously influence.The seed growth method by still using FeCO₃ as a precursor in solvent thermal decomposition expand the scope of particle size to 20nm.(3)Characterization of different metal ion carbonates and their application in the synthesis of ferrite nanoparticles:The manganese carbonate,zinc carbonate,cobalt carbonate,and basic nickel carbonate were characterized by TGA and employed as precursors to synthesize their ferrite nanoparticles.9 nm manganese ferrite particles,15 nm zinc ferrite particles,9 nm cobalt ferrite particles,and 13 nm nickel ferrite particles were successfully prepared.It was found that the as-prepared ferrite nanoparticles had regular shapes,good crystallinity,and excellent magnetic properties.