Synthesis And Research Of Nano-flake Hydrotalcite And Magnetic Nanoparticles

In recent years,magnetic nanomaterials have attracted extensive attention.Because of the unique properties of magnetic nanomaterials,they are widely used in machinery,national defense,military industry,biomedical,public health,energy,electricity,storage and many other fields.For the application of magnetic nanomaterials,it is very important to find an efficient and convenient method to prepare magnetic nanoparticles.Because of its unique layered structure,LDHs have bright application prospects in heat stabilizer,flame retardant,adsorption,medical carrier,catalysis,magnetism,light,electricity,etc.Its unique structure allows the metal ions in the lamellae to exist in the form of a unique single ion layer.Therefore,hydrotalcite has potential in the preparation of magnetic nanomaterials.At present,there are many ways to prepare hydrotalcite,such as ion exchange method,roasting oxide recovery method,co-precipitation method,etc.These methods through in-depth study,researchers have made the optimized reaction conditions,such as can be prepared with the original structure of the same kind of hydrotalcite containing different anion,multivariate hydrotalcite or good crystallinity hydrotalcite,etc,but individual there was defect,such as complicated preparation process,need in particular temperature experiment,the products are not uniform,and so on.Solution reaction method and the water thermal response of class prepared by hydrotalcite uniform shape,with nanoscale layer structure,method is simple and quick,the synthesis class hydrotalcite nano piece of high purity,and can manipulate reaction conditions to control the morphology of the product,in the laboratory solution reaction method and the water thermal response method is the preparation of high quality class hydrotalcite nano piece of the commonly used method.In this paper,CoCl₂,FeCl₂,Ni SO₄ containing transition metal salt solution,and ammonia or urea as the reaction solution,using hydrothermal synthesis method and solution reaction method directly generated homogeneous,good crystallinity of Co-Al-LDHS,Fe-Al-LDHS and Ni-Al-LDHS nanosheets.The structure and morphology were studied.The effects of reaction time,reaction temperature,alkali concentration and alkali type on the products during the growth of hydrotalcite-like nanosheets were discussed.The results show that when ammonia is used as alkali solution,the nanosheets are interlinked and grow with each other.The shape of the nanosheets is irregular and most of the nanosheets grow almost vertically on the aluminum substrate.When urea was used as alkali solution,the nanosheets showed obvious hexagonal shape,and their thickness was significantly higher than that of the product when ammonia was used as alkali solution.The growth mechanism of hydrotalcite-like nanosheets was studied.The growth of LDHs starts from the crystal nucleus forming LDHs,and then the crystal nucleus continues to grow into hydrotalcite like nanosheets.Weak base is similar to ammonia water and urea,which is beneficial to the formation of hydrotalcite-like nanosheets with good morphology.The structure and magnetic properties of the products obtained by reducing hydrotalcite nanosheets in hydrogen atmosphere were studied.Results show that the metal cation in magnetic metal nanoparticles form is restored,resulting from the reduction of particle size at the nanometer order of magnitude,uniform size,and a magnetic,nanoparticles embedded in the precursor and did not destroy the precursor of the original sheet structure,magnetic nanoparticles is stable at room temperature,They have many new properties that will make them as catalyst materials,magnetic fluid materials and magnetic recording materials.