نتایج جستجو برای: pt nanoparticles
تعداد نتایج: 151395 فیلتر نتایج به سال:
A high-temperature and high-pressure flow-reactor system was applied to the synthesis of monometallic ruthenium (Ru) nanoparticles and platinum/ruthenium (Pt/Ru) bimetallic nanoparticles using the thermal reduction of ruthenium ion (Ru(III)) and the mixture of platinum (Pt(IV)) and ruthenium ions in water and ethanol mixture in the presence of poly(N-vinyl-2-pyrrolidone). Monometallic Ru nanopa...
Electrocatalysis of oxygen reduction using Pt nanoparticles supported on functionalized graphene sheets (FGSs) was studied. FGSs were prepared by thermal expansion of graphite oxide. Pt nanoparticles with average diameter of 2 nm were uniformly loaded on FGSs by impregnation methods. Pt-FGS showed a higher electrochemical surface area and oxygen reduction activity with improved stability as com...
The nucleation of noble metal nanoparticles on oxide surfaces can lead to dramatic enhancements in catalytic activity that are related to the atomic-scale formation of the nanoparticles and interfaces. For the case of submonolayer Pt deposited on the 2×1 SrTiO(3)(001) surface atomic-force microscopy shows the formation of nanoparticles. We use X-ray standing wave (XSW) atomic imaging to show th...
Due to its special electronic and ballistic transport properties, graphene has attracted much interest from researchers. In this study, platinum (Pt) nanoparticles were deposited on oxidized graphene sheets (cG). The graphene sheets were applied to overcome the corrosion problems of carbon black at operating conditions of proton exchange membrane fuel cells. To enhance the interfacial interacti...
A new method for the preparation of Pt-Ru and similar bimetallic electrocatalysts is reported. It involves a spontaneous deposition of Pt submonolayers on metallic Ru nanoparticles, which yields electrocatalysts with a considerably lower Pt loading and higher CO tolerance than the commercial Pt-Ru alloy electrocatalysts. The method offers a unique possibility to place the Pt atoms onto the surf...
We report Pt-Pd nanoparticles synthesized by means of a polyol process with glycerol as a reducing agent. The Pt-Pd nanoparticles exhibit dominantly exposed {111} facets in octahedral shape with complete alloy formation between Pt and Pd. Furthermore, the octahedral Pt-Pd alloy catalysts show improved catalytic activity and stability in methanol electrooxidation.
the silica supported platinum nanoparticles was synthesized by using the sol-gel method. the possibility of using diamminedinitro platinum (ii) as pt precursor and effect of metal precursor concentration on the final pt nanoparticle size was investigated. a stable silica sol was prepared via hydrolysis of tetraethyl orthosilicate (teos) as a metal alcoxide and condensation reaction. subsequentl...
With an eye toward using surface morphology to enhance heterogeneous catalysis, Pt nanoparticles are grown by atomic layer deposition (ALD) on the surfaces of SrTiO(3) nanocubes. The size, dispersion, and chemical state of the Pt nanoparticles are controlled by the number of ALD growth cycles. The SrTiO(3) nanocubes average 60 nm on a side with {001} faces. The Pt loading increases linearly wit...
This paper discusses the mechanisms of surface area loss of supported platinum (Pt) electrocatalysts in lowtemperature fuel cells. It is argued that submonolayer dissolution of Pt nanoparticles governs the surface area loss at high voltages by increasing the loss of Pt from carbon and coarsening of Pt nanoparticles on carbon.
Precisely tailoring the structure and fully making use of the components of nanoparticles are effective to enhance their catalytic performance for a given reaction. We herein demonstrate the design of cage-bell structured Pt-Pd nanoparticles, where a Pd shell is deliberately selected to enhance the catalytic property and methanol tolerance of Pt for oxygen reduction reaction. This strategy star...
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