Study Of Rapid And Controllable Method To Large-scale Pt-based Catalyst

Platinum nanoparticle have been widely used in the petroleum cracking and restructuring, fuel cells, nano instrument, fine chemical engineering and chemical and pharmaceutical due to their unique ability to both the redox reactions. Formation of nanocomposite material not only collect the performance of a single platinum material, but also have unique properties after assembly of various materials as the bimetallic synergetic effect. Consequently, platinum-based nanocomposite catalysts own infinite potential for direct applications. Although platinum-based nanocomposite catalysts have made a lot of progress in the liquid-phase synthesis, there is still a space in the actual commercial applications. This paper foucs on searching for new method of controllable synthesizing macroscopic platinum nanoparticles and controllable and compositions of platinum-based catalysts proceeds analysis.The main results and progresses are summarized as follows:(1) The small size Pt nanoparticles were synthesized in high concentration by polyalcohol reduction method, which dispersed in water showed high quality colloidal solution. Platinum nanoparticles of various sizes ranging from 2-9 nm were rationally produced by tuning the proportion of ethylene glycol and water in the reaction precursor. The influence factors including reaction temperature, concentration of precursors and surfactant, the types of alcohol for formation of small size platinum nanoparticles were systematically investigated.Compared with commercial Pt/C catalyst the as prepared platinum nanoparticles exhibited excellent catalytic activities toward hydrolysis of ammonia borane.(2) We report an one-step method for synthesising Pt-Pd cage-like nanoparticles with uniform size, porous shell and hollow interior structure. The influence factors including reaction temperature, surfactant, concentration of precursors for formation of Pt-Pd metallic nanocages were systematically investigated. Pt-Pd metallic nanocages of various sizes and compositions were rationally produced by tuning the experimental parameters. It has revealed that the electrocatalytic activity of Pt-Pd metallic nanocages toward methanol oxidation(MOR) is higher than that of monometallic Pt NPs and Pd NPs about 3.3 times catalytic activity of the existing carbon platinum catalysts.(3) Gold octaher(Au NPs) were used as suspended nanoscale substrates for the deposition of Pt and Ag atoms in the tip of the Au NPs, gold@silver platinum nanoparticles(Au@AgPt NPs) with concave structure were successfully prepared in the glycol system through seeded growth methodwith uniform size. The success of our approach relies on the relatively high reduction rate at a sufficiently high temperature to limit Pt and Ag atoms to spread across the entire surface of a Au seed from the initially deposited sites to generate concave Au@AgPt NPs. Prepared Au@Ag Pt NPs were showed superior stability in the water and ethylene glycol, Products were stored for long periods and were unlikely to occur agglomeration or distortion at ambient temperature. What's more, Au@Pt core-shell NPs and Au@Ag nanosphere were rationally produced by tuning the experimental parameters. It has revealed that the catalytic activity of concave Au@AgPt NPs toward reaction of p-nitrophenol is higher than that of monometallic Au NPs.