Fabrication Of Magnetic Nanomaterials And Their Applications In Analytical Chemistry And Catalysis

In recent years,people pay attention to the catalytic degradation and testing of organic pollutants as well as the analysis of health-related substances.Due to natural and human environment is complex and difficult remediation,it is greatly significant to preparate the catalysts with high cycle catalytic rate and controllable catalytic activity as well as the establishment of nondestructive and rapid detection method.With the development of nanotechnology,the magnetic responsiveness of magnetic nanomaterials has important research value in solving these problems above.In this thesis,we have synthesized Fe3O4-AuNPs and Fe3O4-AgNPs composites,which exhibited good SERS and catalytic properties.Main contents are summarized as follows:(1)We prepared two types of magnetic responsiveness nanocomposites(600 nm and 40 nm),and carried out XRD,SEM,TEM and hysteresis characterization.The composite were successfully synthesized with homogeneous particle size distribution and exhibited excellent magnetic saturation,up to 59 emug/g.(2)Then,based on the magnetic responsiveness and catalytic activity of these nanomaterials,we investigated their catalytic properties by applying them for NaBH4 catalyzed degradation of methylene blue(MB).In our experiment,the Fe3O4-13 nm-AuNPs was optimized for catalytic degradation,with a catalytic degradation rate of up to 92%in five minutes.At the same time,At the same time,the catalytic properties and morphology of the catalyst remained unchanged after 3-cycles.Moreover,after six months,the catalytic performance of the catalyst remained almost unchanged.(3)In addition,we investigated the SERS performance of Fe3O4-30 nm-AuNPs?Fe3O4-AuNIs,and Fe3O4-AgNPs.We found the SERS performances of Fe3O4-AuNIs and Fe3O4-AgNPs were better than that of Fe3O4-30 nm-AuNPs,suggesting the influence of material composition and morphology on their SERS performance.Despite their good SERS activity,the synthetic process of Fe3O4-AuNIs was complicated,and Fe3O4-AgNPs were more easily oxidized.Hence,we chose Fe3O4-30 nm-AuNPs as the SERS substrate in the following study and applied them for the SERS detection of R6G.The detection limit was as low as 10 nM.