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The goal of this work is to understand how the phase diagram of the platinum-palladium (Pt-Pd) alloy changes with size and shape and how it correlates with catalytic properties. By using nano-thermodynamics, the size and shape effects on the phase diagram of Pt-Pd nanoparticles were determined theoretically. The phase diagram of some nanoparticles (sphere, tetrahedron, octahedron, decahedron, cube, cuboctahedron and rhombic dodecahedron) exhibits a congruent melting point that becomes more and more pronounced when the size decreases. At the right of the congruent melting point i.e. close to the Pt-rich side, the coexistence region exhibits a contraction while an expansion is noticed at larger palladium concentrations. From the Gibbs free energy analysis, the stability of all the considered shapes has been determined versus temperature and composition. Furthermore, the surface segregation was also calculated and it is shown that the surface segregation is reversed at very small sizes. Indeed, below a critical size, Pd does not segregate anymore at the surface like it normally does for larger nanoparticles; but Pt does. The critical size range has been determined for each considered shape; and within this range Pt and Pd co-exist at the surface. Finally, the most catalytically active shapes are predicted to be the tetrahedron and the cube in agreement with the available experimental data and other theoretical results.
This article was published in the following journal.
Bimetallic nanocatalysts are key enablers of current chemical technologies, including car exhaust converters and fuel cells, and play a crucial role in industry to promote a wide range of chemical rea...
Increasing the catalyst's stability and activity are one of the main quests in catalysis. Tailoring crystal surfaces to a specific reaction has demonstrated to be a very effective way in increasing th...
The reduction of bromate to bromide was successfully achieved by bimetallic catalysts with NZVI support in continuous-flow reactors. The stability of NZVI-supported bimetallic catalysts was enhanced b...
Most of nanomaterials composed of hyaluronic acid (HA) used for drug targeting are spherical. In this investigation, we suggest that the morphology of HA nanomaterials could be considered as a new par...
In this work, nano-bimetallic Co/Fe oxides with different stoichiometric Co/Fe ratios were prepared using a novel one-step solution combustion method. The nano-bimetallic Co/Fe oxides were used for su...
This prospective, open label, muti-center study evaluates the use of Nano-Pulse Stimulation (NPS) in the treatment of Sebaceous Hyperplasia (SH) lesions less than 2.5mm in size.
This study is an open-label, prospective pharmacokinetic study investigating two antiretroviral agents in parallel and employing an adaptive design with two stages, whereby the results obt...
This study will investigate the effectiveness of nanohydroxyapatite (nano-HAP)-containing toothpastes and cream to relieve dentin hypersensitivity, comparing it with those of a commercial ...
The primary purpose of this trial is to evaluate Nano-Pulse Stimulation (NPS) to clear or remove Seborrheic Keratosis (SK) lesions from off-facial areas of healthy adult subjects.
The aim of this study was to evaluate the effect of nanohydroxyapatite associated with low potency laser therapy in eliminating or reducing dentin hypersensitivity in a randomized placebo-...
The series of changes to the shape, size, components, and functions of an individual organism that occur over time as the organism progresses from its initial form to full size and maturity.
A condition in which the ocular image of an object as seen by one eye differs in size and shape from that seen by the other.
The scientific study of variations in size, shape, and proportion of the cranium.
Alterations or deviations from normal shape or size which result in a disfigurement of the foot.
Alterations or deviations from normal shape or size which result in a disfigurement of the hand.
Collaborations in biotechnology
Commercial and academic collaborations are used throughout the biotechnology and pharmaceutical sector to enhance research and product development. Collaborations can take the form of research and evaluation agreements, licensing, partnerships etc. ...