نتایج جستجو برای: pt nanoparticles
تعداد نتایج: 151395 فیلتر نتایج به سال:
The study of the adsorption and growth of metals on ceramics is a rapidly growing area, as these interactions are key to understanding many materials and processes used in modern technology. In particular, oxide-supported catalysts have been extensively studied, due to their widespread industrial applications. Knowledge of the role played by the underlying metal oxide in the reactivity of the m...
Background So far, most of studies on nanometer-sized metal particles have focused on biological safety and potential hazards. However, anti-oxidative activity of noble metal nanoparticles (NPs) attracts much attention, recently. Platinum nanoparticles (Pt NPs) are one of the most important noble metals in nanotechnology because Pt NPs have negative surface potential from negative charges and a...
Experimental results of a smooth composition gradient within Pt/Pd alloy nanoparticles with Pt enrichment at the corners are reported. We find that the Pt concentration gradually increases toward the outermost surface, and it appears different from the thermodynamically most stable configuration. We demonstrate that it is the result of reaction kinetics of both the reduction of precursors and g...
Tungsten carbide (WC) is a widely used engineering material which is usually prepared at high temperature. A new mechanism for synthesizing nanoscaled WC at ultralow temperature has been discovered. This discovery opens a novel route to synthesize valuable WC and other carbides at a cost-efficient way. The novel formation mechanism is based on an ion-exchange resin as carbon source to locally a...
Mastery over the structure of nanomaterials enables control of their properties to enhance their performance for a given application. Herein we demonstrate the design and fabrication of Pt-based nanomaterials with enhanced catalytic activity and superior selectivity toward the reactions in direct methanol fuel cells (DMFCs) upon the deep understanding of the mechanisms of these electrochemical ...
In this study, the electrocatalytic activity of the Co@Pt core-shell nanoparticles toward the ethanol oxidation reaction has been investigated by cyclic voltammetry and chronoamperometry in acidic and alkaline media in details. The physicochemical data obtained in alkaline solution are compared to those in acidic solution. The obtained results demonstrate that while in the both media Co@Pt core...
Here we report on the effect of the mass transfer rate (k(t)) on the oxygen reduction reaction (ORR) catalyzed by Pt dendrimer-encapsulated nanoparticles (DENs) comprised of 147 and 55 atoms (Pt(147) and Pt(55)). The experiments were carried out using a dual-electrode microelectrochemical device, which enables the study of the ORR under high k(t) conditions with simultaneous detection of H(2)O(...
fept nanoparticles with thermally stable room-temperature ferromagnetism are investigated. the monodisperse nanoparticles are prepared by chemical synthesis and a salt-matrix annealing technique. structural and magnetic characterizations confirm the phase transition from the disordered face-centered cubic structure. in this paper, 3 nm fept nanoparticles are first synthesized by superhydride re...
The effects of particle composition on heterogeneous catalysis were studied using dendrimer-encapsulated nanoparticles (DENs) as precursors to supported Pt-Cu catalysts. Bimetallic Pt-Cu DENs with varying Pt/Cu ratios were prepared in an anaerobic aqueous solution and deposited onto a high-purity commercial alumina support. The dendrimer template was then thermally removed to yield supported na...
Theoretical/computational methods have been extensively applied to screen possible nano-structures attempting to maximize catalytic and stability properties for applications in electrochemical devices. This work shows that the method used to model core@shell structures is of fundamental importance in order to truly represent the physicochemical changes arising from the formation of a core-shell...
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