When more Ni atoms entered into the Pd lattice, it can result in the decrease of the lattice parameter and the Pd—Pd interatomic distance because the radius of the Ni atom was smaller than that of the Pd atom [ 27 ].
The lattice distances were found to be 0. This method revealed that the binding energy of Pd 0 3d The results, given as percentages of total intensity, are presented in Table 1.
Results and Discussion 3. This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Introduction Although proton exchange membrane fuel cells PEMFCs are recognized as a promising form of technology to meet the global energy crisis and address various associated environmental problems, many technical and economic challenges prevent their large-scale commercialization, one of which is the high cost of platinum [ 1 ].
In this study, we prepared a Pt monolayer core-shell catalyst with a ternary PdIrNi alloy nanoparticle as the core using an underpotential deposition UPD method.
What is more, a clear negative shift of ca.
However, most current core-shell catalysts still use precious metals such as Pd [ 2122 ] as the cores, and this makes it difficult to reduce the cost of catalysts effectively. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst.
This prepared electrode bearing the core-shell structured catalyst was used for the subsequent electrochemical performance measurements without further treatment.
Abstract We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. The binding energy was calibrated by means of the C 1s peak energy of A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core.
To address this problem, some studies have introduced nonprecious metals into the alloy nanoparticles, yielding cores such as PdCo, PdNi, and PdFe [ 23 — 25 ]. There may be two reasons: Palladium chloride, iridium chloride, and nickel chloride in an atomic ratio of 1: Results of fitting the XPS spectra; values given in percentage of total intensity.
Clearly, the diffraction peak for the catalysts shifted positively as the Ni content increased, and the lattice parameters decreased obviously with the increase of the content of nickel. In recent years, the emergence of core-shell catalysts [ 8 — 12 ], especially those with a Pt monolayer [ 13 — 20 ], has brought PEMFC commercialization closer to becoming a reality, because the mass activity of Pt in a core-shell catalyst can be enhanced by several times.
The diameters of both nanoparticles increased by ca. It can be observed that all of the nanoparticles were well dispersed on the carbon support without apparent aggregation either before or after the Pt deposition.
To further understand this excellent mass activity enhancement and the role of Ni, we measured the real composition of all the catalysts, as shown in Table 2. The decrease of interplanar spacing was caused by the force between the core and the Pt shell. The atomic radii of Pd, Ir, and Ni atoms are 1.
The negative shift of the Pt 4f binding energy implied that the Pt nanoparticles can get electrons from the alloy core, leading to a weakened interaction between intermediate oxide species and Pt atoms that the ORR was improved [ 28 ].
Next, a Cu monolayer was deposited on the surface of the PdIrNi nanoparticles in a 0.
The first peak, located at about However, catalyst stability has remained a problem.The Fe Ni invar alloy with its negligible thermal expansion coefficient is thus a natural choice for this application.
Here, we use density functional theory as implemented through the Korringa-Kohn-Rostoker method within the coherent-potential approximation, to design new alloys with the large magnetization desired for smart.
The beta phase of alloys lying on the low titanium side of a tie line between 7% chromium and 4% iron is retained upon water quenching from the beta space.
EFFECT OF CHEMICAL COMPOSITION OF SECONDARY Al-Si CAST ALLOY ON INTERMETALLIC PHASES. Ing. Hurtalová L. 1PhD The mechanical properties of Al-Si alloys depend, besides the Si, Cu, Mg and Fe-content, more on the distribution and alloys can often be used directly in new cast products for mechanical engineering, in.
姓名：李博 性别：男. 出生年份： 职称：教授. 首次聘任导师时间： 现聘任导师一级学科名称：物理学. 现聘任导师二级学科名称：等离子体物理. Preparation and Characterization of New Ternary Fe-Ni-Cu Invar alloys S Ahmada, A B Ziya, a, A Ibrahimb, S Atiqb, N Ahmada and F Bashirc. Structure and Performance of SelectiveHydrogenation Catalysts • Ternary systems: Cu Ni Fe 2 and Ni 3 Sn alloy phases were foundto.Download