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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.
Prof. Giuseppe Battaglia and his group at University College in London have performed high resolution imaging of Ferritin proteins in liquid using a DENSsolutions Ocean In situ liquid system and a Gatan K2-IS. We are looking at objects as small as 10 nm imaged at a resolution close to 1 nm. These preliminary results highlight once more the importance of Liquid Phase Electron Microscopy (LP EM) and the need for a stable and reliable liquid cell solution
Researchers at Zhejiang University, using a DENSsolutions Climate S3+, have performed an atomic scale TEM observation of shape evolution of Pd nanocrystals under oxygen and hydrogen environments at atmospheric pressure. By combining imaging with multi-scale structure reconstruction model calculations, they have been able to fully understand the reshaping mechanism. The work has deserved the back cover page of the Chemical Communications journal.
On the way towards more accurate understanding of the dynamics under gas atmosphere, Ernst Ruska-Center for Microscopy and Spectroscopy with Electrons has launched a Master Student Project that will deal with the challenges of beam effects on catalyst nanoparticles under gas environment. More specifically, in this project a systematic study on the effect of electron dose on the DENSsolutions Climate Nano-Reactor will be carried out as well as on the catalyst nanoparticles, with the aim of determining the optimum dose level in the trade-off between damage and signal. Characterizing the effect of the electron beam will result in a greater understanding of in-situ experiments in the electron microscope in order to bridge the ‘pressure-gap’. Towards the end of the project the optimized dose will be used to look at Pt/carbon catalysts for hydrogen fuel-cell applications.
Are you interested? Download the full job description
In-situ electron energy loss spectroscopy (EELS) is of immense value when studying the chemical structure of functional materials at the atomic scale1. This webinar will introduce the types of information you can obtain using in-situ EELS. Practical examples will be shown by reviewing published in-situ EELS work as well as unpublished in-situ EELS videos obtained using the GIF Quantum® K2 IS system from Gatan.
In the second part of this webinar, we will look more closely at the accuracy of the in-situ heating that is required for each of the experiments presented. MEMS-based heating will be specifically discussed since these holders are now widely used to improve stability at elevated temperatures. We will discuss the technology behind DENSsolutions heating solutions as well as methods, including one EELS-based technique, used to confirm the temperature accuracy of the sample.