The Preparation And Application Of Several New Carbon Based Noble Metal Nanomaterials

Owing to the advantages of good conductivity,biocompatibility,catalytic activity and optical properties,noble metal nanoparticles have been widly applied in catalysis,electrochemistry and analytical chemistry areas.Carbon nanomaterials such as graphene and multi-walled carbon nanotubes have attracted considerable interest because of their high surface area,chemical stability,high electrical conductivity and fast electron transfer rate.In addition,C-dots are quasi-spherical nanoparticles and have good properties such as desirable biocompatibility,nontoxicity,reducibility.Owing to the special properties of carbon dots,it may be used as the reductant and stabilizer to prepare noble metal nanoparticles.The combination of noble metal nanoparticles and carbon nanomaterials not only keep their own excellent properties,but also possess new characteristics because of the synergistic effect.Therefore,carbon-based noble metal nanocomposites have broad application prospects in catalysis,fuel cells and chemical biosensors.Based on the recent research progress of noble metal nanomaterials and carbon materials,several carbon-based noble metal nanocomposites have been prepared and their application were studied in this paper.The main contents are as follows:1.A new nanomaterial of thiol functional ferrocene derivative?Fc-SH?stabilized Au NPs/carbon dots nanocomposite?Au/C NC?coupling with graphene modified glassy carbon electrode?Fc-S-Au/C NC/graphene/GCE?was fabricated to serve as a quadruplet detection platform for ultrasensitive and simultaneous determination ofascorbic acid?AA?,dopamine?DA?,uric acid?UA?and acetaminophen?AC?.The Au/C NC was synthesized by adding HAuCl₄ into carbon nanodots solution without using any additional reductant and stabilizing agent.Then the Fc-SH was utilized as the protective and capping agent to modify the Au/C NC.Transmission electron microscopy?TEM?,UV-Vis,Fourier-transform infrared?FT-IR?,scanning electron microscopy?SEM?,cyclic voltammetry?CV?,electrochemical impedance spectroscopy?EIS?were adopted to characterize the morphology and electrochemical properties of the materials and the electrodes.The Fc-S-Au/C NC/graphene/GCE exhibits synergistic catalytic and amplification effects towards oxidation of AA,DA,UA and AC owing to the existence of the nanomaterial and electron mediator.When simultaneous detection of AA,DA,UA and AC,the oxidation peak potentials of the four compounds on the electrode can be well separated and the peak currents were linearly dependent on their concentrations.The quadruplet detection platform shows excellent linear range and ultrasensitive response to the four components,the detection limits were estimated to be as low as 1.00,0.05,0.12 and 0.10?M?S/N=3?,and the modified electrode exhibits excellent stability and reproducibility.The proposed electrode has been successfully applied to detect of these four analytes in real samples with satisfactory results.2.Carbon-based AuPd bimetallic nanocomposite?AuPd/C NC?was synthesized using carbon dots?C-dots?as the reducing agent and stabilizer by a simple green sequential reduction strategy,without adding other agents.The as synthesized AuPd/C NC showed good catalytic activity and peroxidase-like property.The structure and morphology of these nanoparticles were clearly characterized by UV-vis spectroscopy,X-ray photoelectron spectroscopy?XPS?and transmission electron microscopy?TEM?.The AuPd/C NC catalyst exhibits noticeably higher catalytic activity than Pd and Au nanoparticles in catalysis reduction of4-nitrophenol?4-NP?.Moreover,based on the high peroxidase-like property of AuPd/C NC,a new colorimetric detection method for hydrogen peroxide?H₂O₂?has been designed using3,3',5,5'-tetramethyl-benzidine?TMB?as the substrate,which provides a simple and sensitive means to detect H₂O₂ in wide linear range of 5mM-500 mM and 500 mM-4 mM with low detection limit of 1.6 mM?S/N=3?.Therefore,the facile synthesis strategy for bimetallic nanoparticles by the mild reductant of carbon dot will provide some new thoughts for preparing of carbon-based metal nanomatials and expand their application in catalysis and analytical chemistry areas.3.A facile one-pot method for preparingAuPd bimetallic incorporated carboxylic multi-walled carbon nanotubes?MWCNT-PDDA-AuPd?was developed and the effect of the trace palladium on the catalytic properties of MWCNT-PDDA-AuPd was investigated.The nanomaterials are mainly characterized by transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?.Results showed that trace palladium has great influence on the catalytic effect of the methanol oxidation reduction?MOR?and oxygen reduction reaction?ORR?in alkaline media.The as-prepared MWCNT-PDDA-AuPd shows enhanced electrocatalytic performance toward ORR which is mainly predominated by a four-electron pathway,and displays improved catalytic activity and high stability for MOR.At the same time,the catalytic effect of the bimetallic based nanomaterial is better than those of homologous monometallic counterparts and the commercial Pd/C.Compared with free-palladium and different amount of palladium in the composites of MWCNT-PDDA-AuPd,the catalytic effect of MWCNT-PDDA-Au₇Pd₃ and the MWCNT-PDDA-Au₈Pd₂ were the best for MOR and ORR.These results demonstrate that the MWCNT-PDDA-AuPd nanocomposite may be an attractive and advanced electrode material with potential applications in fuel cells.