Building of CoFe2/CoFe2O4/MgO architectures: Structure, magnetism and surface functionalized by TiO2

• Published in: Applied surface science Vol. 392; pp. 1078 - 1087
• Main Authors: Wang, M., Ma, Y.Q., Sun, X., Geng, B.Q., Wu, M.Z., Zheng, G.H., Dai, Z.X.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2017
• Subjects: Architecture; CoFe2/CoFe2O4/MgO architecture; Construction; Degradation; Magnesium oxide; Magnetization; Photocatalysis; Photocatalyst; Photocatalysts; Rattle-type nanostructures; Surface functionalization; TiO2; Titanium dioxide; Surface functionalization; CoFe2/CoFe2O4/MgO architecture; Photocatalyst; TiO2; Rattle-type nanostructures
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.09.076

In order to expand the applications of magnetic nanoparticles, nanostructure CoFe2/CoFe2O4/MgO was synthesized. The CoFe2 core has the highest magnetization among all binary alloys, enhancing the response of magnetic nanoparticles to the external magnetic field; The CoFe2O4 shell protects CoFe2 core from oxidation and improve the stability and biocompatibility of magnetic nanoparticles. Some magnetic nanoparticles were functionalized by TiO2. The hollow rattle-type particles were obtained without the assistance of template and etchant, which has been generally used in previous reports. The photocatalytic performance was investigated for the functionalized magnetic nanoparticles. The rattle-type particles exhibited the strong absorption to methylene blue; The highest degradation efficiency reaches 93% for CoFe2/TiO2; CoFe2/TiO2 has the high magnetization, beneficial for the recovery of catalyst after degradation.
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•CoFe2/CoFe2O4/MgO were built for expanding applications of magnetic particles.•Rattle-type photocatalysts were obtained in the absence of template and etchant.•The rattle-type particles exhibited the strong absorption to methylene blue.•The highest degradation efficiency reached 93% for CoFe2/TiO2.•CoFe2/TiO2 can be easily separated due to its high magnetization.
Well-dispersed uniform CoFe2O4 nanoparticles were prepared and then coated by MgO through thermal decomposition of a metal–organic salt in organic solvent. Then CoFe2O4/MgO were reduced in a H2/N2 mixture gas and subsequently oxidized in an ambient atmosphere in order to build CoFe2/CoFe2O4/MgO architectures with high magnetization, good chemical stability and dispersivity, which are useful in some practical applications. MgO can be dissolved by the HCl solution. The surfaces of CoFe2O4, CoFe2/MgO, CoFe2 and CoFe2/CoFe2O4 magnetic particles were functionalized by TiO2 to prepare the magnetically separable photocatalysts. The rattle-type particles were obtained without the assistance of template and etchant. The photocatalytic activity of these photocatalysts in degradation of methylene blue and the magnetic separability were investigated: The nanosheet-shaped TiO2 and rattle-type particles exhibited good photocatalytic performance; The highest degradation efficiency reaches 93% for the CoFe2/TiO2 sample which has the highest magnetization value of 42emu/g, beneficial for the recovery of catalyst after degradation.