Gold–copper (Au–Cu) phases were employed already by pre-Columbian civilizations, essentially in decorative arts, whereas nowadays, they emerge nanotechnology as an important catalyst. The knowledge of the phase diagram is critical to understanding performance a material. However, experimental determination nanophase diagrams rare because calorimetry remains quite challenging at nanoscale; theoretical investigations, therefore, are welcomed. Using nanothermodynamics, this paper presents...

Nanoscience and nanotechnology are among the most widely used terms in modern scientific technological literature. The idea of appeared for first time famous talk “There is plenty room at bottom” given by physicist Richard Feynman American Physical Society meeting Caltech on December 29, 1959. described a process which ability to manipulate individual atoms molecules might be developed, using one set precise tools to build operate another proportionally smaller so down the needed...

Gold/Palladium nanoparticles were fabricated by inert-gas condensation on a sputtering reactor. With this method, controlling both the atmosphere chamber and magnetron power, it was possible to produce with high degree of monodispersity in size. The structure size Au/Pd determined mass spectroscopy, confirmed atomic force microscopy electron transmission measurements. chemical composition analyzed X-ray microanalysis. From these measurements we that technique are able particles 1, 3, 5 nm...

Surprisingly oxidation resistant icosahedral FePt nanoparticles showing hard-magnetic properties have been fabricated by an inert-gas condensation method with in-flight annealing. High-resolution transmission electron microscopy (HRTEM) images sub-Angstrom resolution of the nanoparticle obtained focal series reconstruction, revealing noncrystalline nature nanoparticle. Digital dark-field combined structure reconstruction as well HRTEM simulations reveal that these shell periodicity....

The packing of spheres is a subject that has drawn the attention mathematicians and philosophers for centuries currently attracts interest scientific community in several fields. At nanoscale, atoms affects chemical structural properties material and, hence, its potential applications. This report describes experimental formation 5-fold nanostructures by interpenetrated icosahedral decahedral units. These nanowires, formed reaction mixture metal salts (Au Ag) presence oleylamine, are...

The thermal stability of bimetallic nanoparticles plays a crucial role in their performance applications catalysis, biotechnology, and materials science. In this study, we employ molecular dynamics simulations to investigate the melting behavior Au-Pd with cuboctahedral, icosahedral, decahedral geometries. Using tight-binding potential, systematically explore effects particle size composition on transition. Our analysis, based caloric curves, Lindemann coefficients, orientational order...

We performed a study on bimetallic Au/Pd nanoparticles using aberration corrected electron microscopy along with molecular dynamics simulations to investigate the features of specific atomic sites at surface, which can be related high catalytic activity properties particles. The calculations mimic growth through cooling process from molten solid crystalline structure room temperature. found that final for alloy particles is neither cuboctahedral nor an icosahedral, but complex has very rough...

The study of nanomaterials can be greatly improved with the use aberration-corrected transmission electron microscopy (TEM), which provides image resolutions at level 1 Å and lower. Sub-Ångström resolution yield a new understanding behavior matter nanoscale. For example, bimetallic nanoparticles are extremely important in catalysis applications; addition second metal many cases produces much-improved catalysts. In this paper, we structure morphology Au/Pd particles using primarily high-angle...

Several series of molecular dynamics runs were performed to simulate the melting transition bimetallic cuboctahedral nanoparticles gold−palladium at different relative concentrations study their structural properties before, in, and after transition. The simulations made in canonical ensemble, each covering a range temperatures from 300 980 K, using Rafii−Tabar version Sutton Chen interatomic potential for metallic alloys. We found that temperature has strong dependence on atomic species....

Silver tetrahedral nanoparticles (NP) were synthesized using the inert gas condensation technique. We performed morphological and optical characterization of (NPs) atomic force microscopy (AFM), mass spectroscopy (MS), UV−visible spectroscopy. The Ag NPs produced by modified magnetron sputtering, followed thermalization in a high pressure zone. Along synthesis process, size was controlled through handling flow (Ar He), power, length aggregation optimized parameters to obtain peak on...

We report the formation of Au/Co nanoparticles and their characterization by aberration (Cs) corrected scanning transmission electron microscopy (STEM). The were synthesized inert gas condensation, forming initially core-shell bimetallic crystals. However, after thermal treatment at normal atmospheric conditions, Co changed morphology into a fine layer perfect interface with gold. ordering zone rich in presents fcc arrangement matching gold lattice. atomic analysis on comparison STEM images...

We report the synthesis, structural characterization, and atomistic simulations of AgPd–Pt trimetallic (TM) nanoparticles. Two types structure were synthesized using a relatively facile chemical method: multiply twinned core–shell, hollow particles. The nanoparticles small in size, with an average diameter 11 nm narrow distribution, their characterization by aberration corrected scanning transmission electron microscopy allowed us to probe particles at level. In some nanoparticles, formation...

Silver nanoparticles were synthesized using the inert gas aggregation technique. We found optimal experimental conditions to synthesize at different sizes: 1.3 ± 0.2, 1.7 0.3, 2.5 0.4, 3.7 4.5 0.9, and 5.5 0.3 nm. able investigate dependence of size on synthesis parameters. Our data suggest that clusters (dimers, trimer, etc.) into active zone nanocluster source is predominant physical mechanism for formation nanoparticles. experiments carried out in kept density low, larges by coalescence...

Aberration-corrected electron microscopy (STEM-HAADF) has been used for the first time to understand capping, nature and structure of MoS2 nanotubes. The nanotubes that have obtained various unusual faceted caps presumably arising from presence topological defects. A detailed study capping nanotubes, along with identification are zigzag type carried out using both experimental simulated STEM images. 3R-rhombohedral stacking identified.

Bimetallic nanoparticles of AuPd were synthesized using the inert gas condensation technique, where material is sputtered from a target and particles are formed in an zone. Throughout synthesis process jointly with control atmosphere conditions, region after chamber was kept at fixed temperature, several experimental runs performed 700 1000 °C. The conditions set to produce 5 nm diameter, almost all resulting icosahedral shape small deviations mean size. We analyzed by high-angle annular...

We study the assembling of small gold clusters subject to collisions and close contact coalescence by using molecular dynamics simulations simulate events that occur typically in sputtering process synthesis. Our results support notion kinetics processes strongly determine geometry structure final particle. While impact velocities, relative orientations, initial shape interacting particles are unlikely strictly structural details newly formed particle, we found high temperatures and/or...

Au-core, Au3Cu-alloyed shell nanoparticles passivated with CuS2 were fabricated by the polyol method, and characterized Cs-corrected scanning transmission electron microscopy. The analysis of high-resolution micrographs reveals that these have decahedral structure periodicity, each particles is composed Au core Au3Cu alloyed surrounded surface layer. X-ray diffraction measurements results from numerical simulations confirm findings. From atomic resolution micrographs, we identified edge...

The role that protecting molecules have on the way palladium atoms arrange themselves in nanoparticles prepared at room temperature was studied by analysis of aberration-corrected scanning transmission electron microscopy images and atomistic Langevin dynamics simulations. It found arrangement Pd is less ordered thiolate-protected than amine-protected ones. experimental theoretical data showed disorder ∼3 nm particles promoted strong S–Pd bond sulfide layer surrounds nanoparticles.

The defect structure of bimetallic nanoparticles differs from that particles made a single atomic species. Using high resolution TEM imaging along with molecular dynamics simulations, it is possible to investigate the nature and features these defects. definition local order parameter allows one locate regions different kinds stacking on simulated thus make direct comparison experimental observations.

Bimetallic nanoparticles constitute a promising type of catalysts, mainly because their physical and chemical properties may be tuned by varying composition, atomic ordering, size. Today, the design novel nanocatalysts is possible through combination virtual lab simulations on massive parallel computing modern electron microscopy with picometre resolution one hand, capability analysis at scale other. In this work we show how theoretical calculations characterization can solve some paradoxes...

The thermal characteristics of bimetallic Pt-Pd nanoparticles, both free and graphite-supported, were investigated through molecular dynamics simulations using quantum Sutton-Chen many-body potentials for the metal-metal interactions. graphite substrate was represented as layers fixed carbons sites modeled with Lennard-Jones potential model. melting temperatures nanoparticles estimated based on variations in thermodynamic properties such energy heat capacity. Melting found to be considerably...