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Metal nanoparticles (NPs) dispersed on a high surface-area support are normally used as heterogeneous catalysts. The recent introduction of Gas Cell systems has enabled experimental demonstration of the way structure reconstruction of the NPs occurs in real catalysis. However, the role played by supports in these processes is still unclear. Supports can be very important in real catalysis because of the new active sites at the perimeter interface between nanoparticles and supports.
In this contribution, the DENSsolutions Climate Gas&Heating solution, owing to its unsurpassed experimental flexibility and stability under any condition, has been used to exploit the full power of in situ aberration corrected electron microscopy. Coupled with multiscale model, the experiment clearly shows that the interaction between the support and the gas environment greatly changes the contact surface area between the metal and support, which further leads to the critical change in the perimeter interface.
The dynamic changes of the interface in reactive environments can thus be predicted and be included in the rational design of next-gen supported metal nanocatalysts. In particular, the multiscale model shows quantitative agreement with experimental observations: this enables the understanding of atomic scale structures and, therefore, provides insights beyond the experimental limits.
This time we showcase a very interesting paper that highlights once more the need for extremely stable imaging conditions when performing in situ heating. In this contribution, the authors have imaged octahedral faceted nanoparticles at different temperatures. These particles are highly attractive fuel cell catalysts as a result of their activity for the oxygen reduction reaction (ORR). However, their surface compositional and morphological stability currently limits their long-term performance in real membrane electrode assemblies (MEAs). Specifically, they authors have performed in situ heating of compositionally segregated PtNi1.5 octahedral nanoparticles inside a transmission electron microscope, in order to study their compositional and morphological changes.
“The authors clearly gave a lot of thought to the issues that could be of interest for a potential user during an in situ TEM experiment before starting the redesign of their system” and “I think it is very good that the company is actively engaging with the scientific community by sharing their views and information on the design of their products by submitting a paper to this journal.”
With these words from the reviewers, we are happy to announce that our own contribution to the scientific community, featuring all you need to know about our advanced heating chips, has been published on Ultramicroscopy.
You can download it for free until the 13th of July.
At DENSsolutions we are proud to sponsor the Irvine Materials Research Institute and the International Symposium on Advanced Electron Microscopy and Spectroscopy. The symposium will run from the 6th until the 8th of June.
If you are going to attend do not miss the chance to attend our presentation focused on the latest developments in the field of in situ EM.
“Irvine Materials Research Institute (IMRI) is a newly established interdisciplinary organization under the Office of Research of the University of California, Irvine (UCI). It serves as the cross-campus nexus for materials research at UCI. IMRI operates a wide range of state-of-the-art, open-access user facilities for the characterization of materials, biological samples, and devices from sub-Å to macroscopic length scales – available to all university, industry, and non-profit researchers. It offers advanced techniques and services supported with professional staff.
Following the completion of a major renovation and the establishment of a premier Transmission Electron Microscopy (TEM) facility, the IMRI is now open to serve all university, industry and nonprofit researchers. Poised to become one of the world’s preeminent centers of excellence for the interdisciplinary research, discovery and development of engineered and natural materials, systems and devices, IMRI is home to several of the highest performance Transmission Electron Microscopes (TEM) available in the world today. We are honored to invite you to join us at the grand opening and the International Symposium on Advanced Electron Microscopy and Spectroscopy (SAEMS) and share with you our accomplishments.
The two day symposium will bring together the scientific community working on various aspects of research and development in TEM to encourage the exchange of ideas for the advancement and challenges in atomic scale imaging and spectroscopy. There will be over 50 internationally renowned TEM experts and scientists participating in this event.”
DENSsolutions B.V. is pleased to announce a change in its distribution network. Effective 1st April 2018, we are covering the following territories directly: North America, Japan and India, previously covered by Gatan, Inc.
It is our intention to further consolidate and strengthen our presence in those territories and be even closer to the end users of our systems. .
Should you need more information, please feel free to get in touch with us via firstname.lastname@example.org.
Experimental determination of the energy difference between competing isomers of deposited, size-selected gold nanoclusters
In situ TEM proves once more its key role in understanding properties of real samples. We show the latest publication using a Wildfire in situ TEM heating system, published on Nature Communications, by the group of Prof. Richard Palmer.
The structure and dynamics of nano-systems are controlled by the multi-dimensional potential energy surface (PES), which describes its free energy as a function of configuration. There have been considerable theoretical efforts to determine the ground-state structures and energy differences between competing isomers of nanosytems in general and of nano clusters in particular. Gold clusters have received much theoretical attention due to the role of structure in the catalytic performance. What is needed now is an experimental handle on key parameters of the PES. Understanding the energy difference between structural isomers is important not only for the design of well-defined materials but also for understanding how these materials will work in situ. For example, if a particular structural isomer is unstable, exposure to high temperatures is likely to drive it towards the ground state (i.e. annealing), altering (for better or worse) the characteristics of the system. Such behavior is likely to be relevant to the applications of nanoparticles, which include catalysis, drug delivery and chemical sensing.
The authors have obtained the energy difference between the most abundant structural isomers of magic number Au561 clusters, the decahedron and face-centred-cubic (fcc) structures, from the equilibrium proportions of the isomers. These are measured by atomic-resolution scanning transmission electron microscopy, with an ultra-stable heating stage, as a function of temperature (125–500 °C). The publication shows clearly the benefits of DENSsolutions heating technology which provides not only ultra high mechanical and thermal stability but also across temperature control across the entire temperature range.