Construction And Catalytic Performance Of Platinum-Supported Nanocomposites Based On Carbon Spherical

With the development of nanotechnology,the composite materials of noble metal nanoparticles have important research significance in the field of catalysis,which can not only reduce the agglomeration of noble metal nanoparticles due to small size,high surface energy and strong van der Waals interaction between particles.The composite materials of noble metal nanoparticles are also beneficial for the effective recycling and reuse of precious metal nanoparticles.Carbon nanospheres?CNSs?,graphene and other carbon materials have unique electronic structure,chemically active surface,high electrical conductivity,high chemical stability and good biocompatibility.The combination of precious metal nanoparticles and carbon materials can effectively improve stability and catalytic activity of noble metal nanoparticles.In this paper,platinum-loaded magnetic carbon nanosphere composites and platinum-loaded molybdenum disulfide carbon sphere core-shell composites were prepared using surface-modified carbon spheres as carriers.The catalytic properties have been used by using colorimetric analysis to detect H₂O₂ and electrochemical analysis to detect H₂O₂ and dopamine?DA?.The specific research work is as follows:?1?The best solution was explored for the preparation of carbon spheres and the ferroferric oxide nanoparticles.The structure and morphology were characterized by SEM,TEM,XRD and FT-IR.The results showed that the carbon spheres with the best dispersibility prepared by adding a small amount of acetone with the glucose concentration for 0.25 mol/L,the reaction time for 4 h and the reaction temperature for180°C.The Fe₃O₄ nanoparticles prepared by pyrolysis have good dispersibility and uniform size,and the average size is 7.6 nm.?2?Platinum-loaded magnetic carbon nanosphere composites?Pt/Fe₃O₄/CNSs?were prepared in steps.The structure and morphology were characterized by SEM,TEM,FT-IR,XRD and XPS.The results show that Pt and Fe₃O₄ nanoparticles are uniformly dispersed on the surface of the carbon nanosphere.The Pt/Fe₃O₄/CNSs complex has good peroxidase activity and can catalyze the color reaction of H₂O₂oxidativetheperoxidasesubstrateTMB?3,3',5,5'-Tetramethylbenzidine?.Pt/Fe₃O₄/CNSs,as a peroxidase mimic enzyme,provides a colorimetric detection for H₂O₂ with high sensitivity,wide linear detection range?0.5¹50 mol/L?and low detection limit?0.15 mol/L?.In addition,the Fe₃O₄/Pt/CNSs modified electrode exhibits excellent electrocatalytic activity for H₂O₂,with fast ampere response time?1s?,high sensitivity,wide linear detection range?0.1⁴.6 mmol/L?,and detection limit?0.32?mol/L?.?3?A platinum-loaded molybdenum disulfide carbon sphere core-shell nanocomposite?Pt-MoS₂@CNSs?was prepared in steps.The structure and morphology were characterized by SEM,TEM,Raman,XRD and XPS.The results show that the MoS₂ nanosheets are closely attached to the surface of the carbon sphere as a component for constructing the layered shell,and the Pt nanoparticles are also supported on the carbon nanosphere surface.Based on the catalysis of Pt-MoS₂@CNSs,the peroxidase substrate TMB was oxidized by H₂O₂ to form blue oxTMB,and a convenient and sensitive H₂O₂ colorimetric sensor was constructed.The linear detection range is 0¹50?M and the detection limit is 0.18?mol/L.At the same time,cyclic voltammetry?CV?and Chronoamperometric measurements has used to study the electrocatalytic performance of Pt-MoS₂@CNSs for DA with low concentration detection,fast ampere response time?2 s?,wide linear response range?0.04³.4mmol/L?.In addition,the Pt-MoS₂@CNSs nanomaterial modified electrode also has good stability,reproducibility and selectivity.