In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds ...In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.展开更多
以PEG4000和(NH_4)2SO_4为双水相体系、二异丙胺为沉淀剂,对共沉淀法进行改进,合成了四氧化三铁(Fe_3O_4)纳米粒子。采用XRD、TEM、VSM、FT-IR等对Fe_3O_4进行性能表征,证明所合成的Fe_3O_4粒子为具有反尖晶石结构、稳定性和分散性良好...以PEG4000和(NH_4)2SO_4为双水相体系、二异丙胺为沉淀剂,对共沉淀法进行改进,合成了四氧化三铁(Fe_3O_4)纳米粒子。采用XRD、TEM、VSM、FT-IR等对Fe_3O_4进行性能表征,证明所合成的Fe_3O_4粒子为具有反尖晶石结构、稳定性和分散性良好、尺寸均一、粒径大小为11 nm左右的球形纳米粒子,具备优异的超顺磁性和高磁化强度等特性。同时对反应温度及铁离子浓度比、PEG4000/(NH_4)2SO_4的质量浓度对双水相体系的形成进行条件探索,确定了最优工艺方案为n(Fe2+)∶n(Fe3+)=2∶3、1.0 g Fe Cl2·4H2O、1.2 g Fe Cl3、10 m L二异丙胺,PEG4000/(NH_4)2SO_4双水相体系中PEG4000的质量分数为18%、(NH_4)2SO_4的质量分数为25%,反应温度为60℃,反应时间为1 h。展开更多
文摘In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.
文摘以PEG4000和(NH_4)2SO_4为双水相体系、二异丙胺为沉淀剂,对共沉淀法进行改进,合成了四氧化三铁(Fe_3O_4)纳米粒子。采用XRD、TEM、VSM、FT-IR等对Fe_3O_4进行性能表征,证明所合成的Fe_3O_4粒子为具有反尖晶石结构、稳定性和分散性良好、尺寸均一、粒径大小为11 nm左右的球形纳米粒子,具备优异的超顺磁性和高磁化强度等特性。同时对反应温度及铁离子浓度比、PEG4000/(NH_4)2SO_4的质量浓度对双水相体系的形成进行条件探索,确定了最优工艺方案为n(Fe2+)∶n(Fe3+)=2∶3、1.0 g Fe Cl2·4H2O、1.2 g Fe Cl3、10 m L二异丙胺,PEG4000/(NH_4)2SO_4双水相体系中PEG4000的质量分数为18%、(NH_4)2SO_4的质量分数为25%,反应温度为60℃,反应时间为1 h。
