Syntheses,Properties And Applications Of Novel Multifunctional Polyoxometalates Based Nanocomposites

Polyoxometalates（POMs）seized the attention of chemists due to their unique properties re-lated to photochemical property,redox property and catalytic property,etc.POMs are not only effective in degrading organic dyes in wastewater but also can be used as drug candidates because of their pharmaceutical properties.Nanoparticles also have a wide range of applications in bio-medicine,catalysis and magnetic resonance imaging,etc.Nanocomposites,combining POMs with nanoparticles,not only have the advantages of various component materials,but also exhibit novel features and functions.1/Fe₃O₄,2/Fe₃O₄,3/Fe₃O₄ and 4/Fe₃O₄ nanocomposites were synthesized by combining[Zn（L）₂（H₂O）₂]₂H₂[P₂Mo₅O₂₃]·2H₂O（L=pyridine-2-carboxamide）（1）,[Co（L）₂（H₂O）₂]₂[P₂Mo₅O₂₃]·2H₂O（2）,[Cu（L）₂（H₂O）]H₂[Cu（L）₂(P₂Mo₅O₂₃)]·4H₂O（3）and[Cd（L）₂（H₂O）₂]₂H₂[P₂Mo₅O₂₃]·2CH₃OH（4）with Fe₃O_4.1/Ag/Fe₃O₄,2/Ag/Fe₃O₄,3/Ag/Fe₃O₄ and4/Ag/Fe₃O₄ nanocomposites were synthesized by combining 1-4 with Fe₃O_4.The natural perfor-mances of nanocomposites were analysized by fourier transform infrared spectrometer（FT-IR）,photoluminescence spectrophotometry（PL）,X-ray diffractometer（XRD）,transmission elec-tron microscopy（TEM,including high-resolution TEM）,ultraviolet-visible light absorbance spectrometry（UV-Vis）and vibrating sample magnetometer（VSM）.The adsorption activity of the1/Fe₃O₄,2/Fe₃O₄,3/Fe₃O₄ and 4/Fe₃O₄ nanocomposites were investigated using methylene blue as the probe molecule.The adsorption and degradation activity of the 1/Ag/Fe₃O₄,2/Ag/Fe₃O₄,3/Ag/Fe₃O₄ and 4/Ag/Fe₃O₄ nanocomposites were investigated using methylene blue as the probe molecule.The subject of the work is summarized as follows:1.Syntheses,properties and applications of POM/Fe₃O₄ nanocompositesMultifunctional high-performance 1/Fe₃O₄,2/Fe₃O₄,3/Fe₃O₄ and 4/Fe₃O₄ nanocomposites were successfully synthesized by combining 1-4 with Fe₃O₄ nanoparticles.The transmission electron microscopy（TEM）analyses show 1/Fe₃O₄ and 2/Fe₃O₄ virtually uniform,spherical in shape with the narrow particle size distribution,high crystallinity.The X-ray diffractome-ter（XRD）measurements indicate the existence of Fe₃O₄ nanoparticles and POM.The fourier transform infrared spectrometer（FT-IR）studies further certify that the nanocomposites contain Fe₃O₄ nanoparticles and POM.The ultraviolet-visible light absorbance spectrometry（UV-Vis）and photoluminescence spectrophotometry（PL）results show that the nanocomposites have excellent absorption and emission abilities.The vibrating sample magnetometer（VSM）results indicate that the nanocomposites display soft ferromagnetic and/or near superparamagnetic behavior at room temperature.The adsorption activity of the 1/Fe₃O₄ nanocomposites was investigated using meth-ylene blue as the probe molecule.The results reveal that the 1/Fe₃O₄ nanocomposites have adsorp-tion behavior for organic dyes.The 1/Fe₃O₄,2/Fe₃O₄,3/Fe₃O₄ and 4/Fe₃O₄ nanocomposites are promising for adsorption,magnetic and biomedical applications.2.Syntheses,properties and applications of POM/Ag/Fe₃O₄ nanocompositesMultifunctional high-performance 1/Ag/Fe₃O₄,2/Ag/Fe₃O₄,3/Ag/Fe₃O₄ and 4/Ag/Fe₃O₄nanocomposites were successfully synthesized by combining 1-4 with Ag/Fe₃O₄ nanoparticles.The transmission electron microscopy（TEM）analyses show 3/Ag/Fe₃O₄ virtually uniform,spherical in shape with the narrow particle size distribution,high crystallinity.The X-ray diffractometer（XRD）measurements indicate the existence of Ag/Fe₃O₄ nanoparticles and 3.The fourier transform infrared spectrometer（FT-IR）studies further certify that the nanocomposites contain Ag/Fe₃O₄ nanoparticles and 3.The ultraviolet-visible light absorbance spectrometry（UV-Vis）results show that the nanocomposites have excellent absorption abilities.The vibrating sample magnetometer（VSM）results indicate that the nanocomposites display soft ferromagnetic and/or near superparamagnetic behavior at room temperature.The adsorption and degradation activity of the 3/Ag/Fe₃O₄ nanocomposites was investigated using methylene blue as the probe molecule.The results reveal that the 3/Ag/Fe₃O₄ nanocomposites have adsorption and degradation behavior for organic dyes suggesting that the nanocomposites have a promising future for wastewater purifications.