Preparation Of Nable Metal Nanoparticles Supported On Carbon And Their Applications In Electroanalytical Chemistry

Noble metal nanoparticles (NMNPs) supported on carbon is a kind of very promising functional nanomaterial, which combines the respective advantages. It is widely used in various fields of electrochemistry. In this thesis, the author prepared several kinds of NMNPs supported on carbon nanotubes (CNTs) and graphene through facile spontaneous redox methods, and their applications were studied in electrocatalysis and electroanalysis. This thesis is divided into four chapters, including:In chapter I, the development of nanomaterials, the preparation and applications of noble metal nanoparticles supported on carbon materials, and the preparation of modified electrodes have been introduced.In chapter II, PdNPs were deposited on the surfaces of multi-walled carbon nanotubes (MWCNTs) spontaneously. Then, the composite nanomaterials were used as electrode modified material for electrochemical catalytic study and analytical applications. After a series of characterization, the growth mechanism was investegated. MWCNTs were dispersed in aqueous solution by cetyl trimethyl ammonium bromide (CTAB). Due to the difference between PdCl42- reduction potential and CNTs oxidation potential, PdNPs with fine size were generated on the MWCNTs by direct spontaneous reduction of the metallic precursor. In addition, due to the highly conducting network of MWCNTs with intact structure and the well-dispersion of ultrafine PdNPs, the as-prepared PdNPs-CNTs exhibited extraordinary electrochemical catalytic behavior toward the oxidation of ethanol and glucose, based on which, a non-enzymatic electrochemical method was developed for glucose detection.In chapter Ⅲ, RGO was used to load PtPd nanodendrites (PtPdND). Then the composite nanomaterials were applied in electrocatalysis of methanol, which is expected as catalyst for methanol fuel cells. After a series of characterization, the growth mechanism was investegated. The specifical preparation process is simple and green. PdNPs monodispersed on RGO surfaces were successfully prepared using the in-situ spontaneous redox reaction between PdCl42- and RGO, which were used as seeds for the subsequent growth of Pt with a porous 3D dendrite-like structure. The as-prepared RGO/PtPdNDs hybrids exhibited higher electrocatalytic activity and better tolerance to pure Pt nanoparticles supported on graphene and commercial Pt/C in the methanol oxidation reaction, due to the synergetic effect of the two metallic components and the graphene.In chapter Ⅳ, ultrafine PdNPs were homogeneously modified on graphene nanosheets through a facile spontaneous redox reaction. Based on the voltammetric and amperometric results, the PdNP-RGO demonstrated direct responses to H2O2 at a low potential. The analytical performances of the PdNP-RGO toward H2O2 reduction was evaluated in the linear response range from 0.1 μM to 1.0 mM, with a detection limit (S/N=3) of 0.05μM. The PdNP-RGO showed excellent resistance toward poisoning from such interfering species as ascorbic acid, dopamine and glucose. Furthermore, the electrochemical sensor presented good characteristics in terms of stability and reproducibility, promising the applicability of this sensor in practical analysis.