A γ-Fe2O3-SiO2 composite was prepared by sol-gel method followed by calcination at 700 ℃ for 30 min starting from tetraethoxysilane and iron nitrate.Upon further coating with SiO2 and TiO2,a TiO2/SiO2/（γ-Fe2O3）-S...A γ-Fe2O3-SiO2 composite was prepared by sol-gel method followed by calcination at 700 ℃ for 30 min starting from tetraethoxysilane and iron nitrate.Upon further coating with SiO2 and TiO2,a TiO2/SiO2/（γ-Fe2O3）-SiO2 magnetic photocatalyst was obtained.XRD results show that Fe in the composite converts to the（γ-Fe2O3） phase up to a processing temperature of 700 ℃,and further increase in temperature results in the formation of the（α-Fe2O3） phase.The TiO2/SiO2/（γ-Fe2O3）-SiO2 samples obtained are monodisperse spherical particles with 200～250 nm diameter,well coated firstly by an amorphous SiO2 layer and then by an anatase TiO2 layer.The TiO2/SiO2/（γ-Fe2O3）-SiO2 particles retain their magnetic property well and show high activity for the photocatalytic degradation of salicylhydroxamic acid.展开更多
The FeS coated Fe nanoparticles were prepared by using high temperature reactions between the commercial Fe nanoparticles and the S powders in a sealed quartz tube. The simple method developed in this work is effectiv...The FeS coated Fe nanoparticles were prepared by using high temperature reactions between the commercial Fe nanoparticles and the S powders in a sealed quartz tube. The simple method developed in this work is effective for large scale synthesis of FeS/Fe nanoparticles with tunable shell/core structures, which can be obtained by controlling the atomic ratio of Fe to S. The structural, magnetic and photocatalytic properties of the nanoparticles were investigated systematically. The good photocatalytic performance originating from the FeS shell in degradation of methylene blue under visible light and the high saturation magnetization originating from the ferromagnetic Fe core make the FeS/Fe nanoparticles a good photocatalyst that can be collected and recycled easily with a magnet. An exchange bias up to tl mT induced in Fe by FeS was observed in the Fe/FeS nanoparticles with ferro/antiferromagnetic interfaces. The enhanced coercivi- ty up to 32 mT was ascribed to the size effect of Fe core.展开更多
文摘A γ-Fe2O3-SiO2 composite was prepared by sol-gel method followed by calcination at 700 ℃ for 30 min starting from tetraethoxysilane and iron nitrate.Upon further coating with SiO2 and TiO2,a TiO2/SiO2/（γ-Fe2O3）-SiO2 magnetic photocatalyst was obtained.XRD results show that Fe in the composite converts to the（γ-Fe2O3） phase up to a processing temperature of 700 ℃,and further increase in temperature results in the formation of the（α-Fe2O3） phase.The TiO2/SiO2/（γ-Fe2O3）-SiO2 samples obtained are monodisperse spherical particles with 200～250 nm diameter,well coated firstly by an amorphous SiO2 layer and then by an anatase TiO2 layer.The TiO2/SiO2/（γ-Fe2O3）-SiO2 particles retain their magnetic property well and show high activity for the photocatalytic degradation of salicylhydroxamic acid.
文摘The FeS coated Fe nanoparticles were prepared by using high temperature reactions between the commercial Fe nanoparticles and the S powders in a sealed quartz tube. The simple method developed in this work is effective for large scale synthesis of FeS/Fe nanoparticles with tunable shell/core structures, which can be obtained by controlling the atomic ratio of Fe to S. The structural, magnetic and photocatalytic properties of the nanoparticles were investigated systematically. The good photocatalytic performance originating from the FeS shell in degradation of methylene blue under visible light and the high saturation magnetization originating from the ferromagnetic Fe core make the FeS/Fe nanoparticles a good photocatalyst that can be collected and recycled easily with a magnet. An exchange bias up to tl mT induced in Fe by FeS was observed in the Fe/FeS nanoparticles with ferro/antiferromagnetic interfaces. The enhanced coercivi- ty up to 32 mT was ascribed to the size effect of Fe core.
