![]() The main conclusions are as follows: sodium citrate - acetone - ethanol system restore photochemical reduction or continuous reduction of Au (III), Pt (IV) ions can be synthesized particles uniformly good monodispersed Au core the Pt shell composite nanoparticles average particle size of 5.1 nm ~ 10.2 nm. ![]() That the dissimilar metal may wish to check the role of the Pt shell is prepared as the main catalyst a high activity. Simple explore the mechanism of the high activity of the composite catalyst. After the cyclic voltammetry (CV) and time - the current (I-T) test, indicating that the two types of catalyst has high catalytic activity and better stability of electro-catalytic oxidation of methanol. The synthesis of Pd-core Pt shell composite nanoparticles as catalytic materials, composite nanoparticles load on the XC-72 carbon black carrier preparation of Pd core Pt shell / C catalyst. According to the experimental phenomena and characterization results of the fine structure of the composite nanoparticles, the growth mechanism of the composite particles. The main contents of the photochemical reduction respectively, in the PEG-acetone system, sodium citrate - acetone - ethanol system Synthesis of Pd nuclear Pt shell and Au core Pt shell composite nano-particles, and the synthesis of nanoparticles tablets diameter, morphology, structure, a more detailed characterization. Improve Pt utilization while the two metals to produce a synergistic effect, greatly improving the electrocatalytic activity of the double precious metal composite nanoparticles. The present Thesis design a relatively inexpensive dissimilar noble metal (relative to Pt purposes) for the nuclear, Pt shell composite nano particles. On the theoretical basis of the original Pt catalyst to new ideas to develop a new type of low-cost, high-performance electro-catalyst is the inevitable trend of low temperature fuel cell technology development, but also double-precious metal composite structure of nano-materials applied research, one of the main directions of. DMFC catalysts, especially the anode catalyst, within a fairly long period of time will also depend on the noble metal. ![]() On the other hand, non-platinum catalyst is still in the exploratory stage, to achieve practical application, there is still a long way to go in the preparation process, stability and catalytic properties. Pt resource scarcity, Pt-based catalysts will be more and more expensive, low Pt loading catalyst technology has almost reached the limits of low load. Judging from the current situation, the Pt-based catalysts are still the main body in the field of low-temperature fuel cell. Direct methanol fuel cell anode catalyst because of its large amount of presence of Pt catalyst the easy poisoning and other issues become the focus of current research. The fuel cell is one of the most important energy power in the 21st century, the direct methanol fuel cell (DMFC), proton exchange membrane fuel cell (PEMFC) give priority to the development of the type of fuel cell. ![]() The Au(core)-Pd(shell) bimetallic nanoparticle system stabilised with citrate was the most successful of the three bimetallic systems studied, producing core-shell particles of approximately 5 nm in diameter.In recent years, double-precious metal composite nanoparticles because of its unique structure and optical, electrical, catalytic properties have been widely used in the field of energy, the environment, biomedical, and become the focus of the scientific community. The second technique studied was the use of galvanic replacement technique for producing bimetallic core-shell nanoparticles, which provides a novel and rapid technique for coating gold nanoparticle seeds with platinum. The thiol-stabilised gold nanoparticles had a better morphology, but the thiol-stabilisation meant that it was difficult to coat the gold nanoparticles. The citrate-stabilised gold nanoparticle seeds provided a better starting material for the bimetallic core-shell nanoparticles, however this route had problems with aggregation and morphology. The gold nanoparticle seeds and the bimetallic core-shell nanoparticles were characterised using UV-vis spectroscopy, HAADF imaging, AFM imaging and with cyclic voltammetry. The gold nanoparticles were stabilised with either citrate or thiol-based stabilisers and the effects of the different stabilisers were studied. Gold nanoparticle seeds were produced using published methods. The transition metals used were platinum, palladium and rhodium. The first technique is the chemical deposition of transition metal salts onto gold nanoparticle seeds. This work reports two novel techniques for synthesising bimetallic core-shell nanoparticles. New fields of research in chemistry and physics require improved synthetic techniques for colloidal metal particles.
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