Rapid Atomic Ordering Transformation toward Intermetallic Nanoparticles

<div> The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi2 to ordered intermetallic Pd3Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi2 corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd3Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions. </div>

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Site preference and atomic ordering in the ternary Rh5Ga2As: first-principles calculations

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2021-2019 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Nilanjan Roy ◽

Sucharita Giri ◽

Harshit ◽

Partha P. Jana

Keyword(s):

Total Energy ◽

First Principles ◽

Density Functional ◽

Structure Type ◽

Site Preference ◽

X Ray Diffraction ◽

Atomic Ordering ◽

Functional Theory ◽

The Stability ◽

Bonding Characteristics

Abstract The site preference and atomic ordering of the ternary Rh5Ga2As have been investigated using first-principles density functional theory (DFT). An interesting atomic ordering of two neighboring elements Ga and As reported in the structure of Rh5Ga2As by X-ray diffraction data only is confirmed by first-principles total-energy calculations. The previously reported experimental model with Ga/As ordering is indeed the most stable in the structure of Rh5Ga2As. The calculation detected that there is an obvious trend concerning the influence of the heteroatomic Rh–Ga/As contacts on the calculated total energy. Interestingly, the orderly distribution of As and Ga that is found in the binary GaAs (Zinc-blende structure type), retained to ternary Rh5Ga2As. The density of states (DOS) and Crystal Orbital Hamiltonian Population (COHP) are calculated to enlighten the stability and bonding characteristics in the structure of Rh5Ga2As. The bonding analysis also confirms that Rh–Ga/As short contacts are the major driving force towards the overall stability of the compound.

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EXAFS-spectroscopy and thermal neutron diffraction study of the effect of deformation by high pressure torsion on the atomic ordering and magnetic properties of the FeCo alloy

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.159021 ◽

2021 ◽

Vol 866 ◽

pp. 159021

Author(s):

A.M. Glezer ◽

L.F. Muradimova ◽

P.A. Borisova ◽

A.A. Veligzhanin ◽

O.V. Chernysheva ◽

...

Keyword(s):

High Pressure ◽

Magnetic Properties ◽

Neutron Diffraction ◽

Thermal Neutron ◽

Diffraction Study ◽

High Pressure Torsion ◽

Neutron Diffraction Study ◽

Exafs Spectroscopy ◽

Feco Alloy ◽

Atomic Ordering

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Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in α,β-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites

Catalysis Science & Technology ◽

10.1039/d0cy02082f ◽

2021 ◽

Author(s):

Muhammad Zahid ◽

Jiang Li ◽

Ahmed Ismail ◽

Francisco Zaera ◽

Yujun Zhu

Keyword(s):

Synergistic Effect ◽

Reduction Method ◽

Synergistic Effects ◽

Acid Sites ◽

Lewis Acid Sites ◽

Unsaturated Aldehydes ◽

Uniform Dispersion ◽

Carbonyl Bond ◽

Method Show ◽

Intermetallic Nanoparticles

PtCo/MIL-101(Cr) with high uniform dispersion Pt–Co IMNs synthesized by a polyol reduction method show higher activity for selective catalytic hydrogenation of α,β-unsaturated aldehydes due to the synergistic effect of PtCo and MIL-101(Cr) support.

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