| ?-Fe2O3 nanomaterials were widely used in many fields for their excellent physical and chemical properties.Here we successfully synthesized pseudo-cube ?-Fe2O3 nanocrystal using Fe(acac)3/PVP composite nanofibers as raw material by hydrothermal process and loaded Pt nanoparticles on the surface of Fe2O3 to explore the thermal stability of the noble metal.Besides,Fe2O3 nanocrystals were found to show the peroxidase mimetic activity.This dissertation research work is as follow:(1)In this dissertation,we first prepared Fe(acac)3/PVP composite nanofibers by electrospinning,and then the porous monodisperse pseudo-cube ?-Fe2O3 nanocrystal with average size about 30 nm is synthesized by controlling the hydrothermal temperature,time,pH of the reaction solution and the concentration of precursor.Here,we use Fe(acac)3/PVP composite nanofibers as the iron resource and PVP from the Fe(acac)3/PVP composite nanofibers as surfactant and morphology control agent.(2)The ?-Fe2O3 nanocrystalline was used as support to disperse 3-5 nm Pt particles,then Pt/?-Fe2O3 were loading on GO sheets in order to anchor Pt/?-Fe2O3 on a position.Indeed,the Pt nanoparticles kept their individual character with stability at temperatures up to 750? in N2,while the Pt/?-Fe2O3 had a reunion at 650?.It demonstrated that Pt/?-Fe2O3/GO had excellent resistance to sintering relative to Pt/?-Fe2O3 because of the corrugated GO sheets blocked the migration of the Pt.The Pt nanoparticles were still catalyzed after calcination at high temperature,as confirmed by a reaction model of hydrogenation of p-nitrophenol.(3)we used the titanium acid nanowires to support the Pt/?-Fe2O3 instead of GO.We found that Pt/?-Fe2O3/titanate nanowires system was difficult to observe the Pt particles in TEM after calcining at 750? in air.But the Pt/?-Fe2O3/titanate nanowires system still had high catalytic activity after calcining at high temperature.(4)This chapter found that under visible light irradiation ?-Fe2O3 nanocrystals can rapidly catalyze the substrate 3,3',5,5'-tetramethylbenzidine(TMB)in the presence of H2O2.It demonstrates that ?-Fe2O3 nanocrystalline has intrinsic peroxidase mimetic enzyme catalytic activity.The catalytic performace was evaluated by UV-Visible spectrophotometer of the colour reaction.The catalytic activity of ?-Fe2O3 single crystal is dependent on pH,H2O2 concentration and illumination as HRP.The results indicated that the Vmax of TMB and H2O2 are much higher than HRP,and ?-Fe2O3 nanocrystals show the higher stability than HRP. |
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