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Introducing our newest team member

You can only be innovative and successful in a high tech field like in-situ TEM if you have a great team. At DENSsolutions we constantly look out for new talent to increase our application expertise. That is why we are very happy that Dr. Dan Zhou, who did her PhD study and second postdoctoral research at the Stuttgart Center for Electron Microscopy (StEM) in Max-Planck Institute for Solid State Research in Stuttgart, Germany, decided to join us.

We interviewed her to learn more about her history, her drive and passion for electron microscopy, and her choice of DENSsolutions.

When did you fall in love with TEM (transmission electron microscopy)?

It started from the last year of my undergraduate study when I was working with SEM (scanning electron microscopy). At that time, the more profound information with much higher spatial resolution from TEM gradually attracted more and more of my interest.

How did you get to know more about TEM?

I started my graduate studies with the basics of electron optics and general TEM techniques at Trinity College Dublin in Ireland. I did some research on different nanomaterials with the basic TEM techniques I had learned, and there I realized I wanted to pursue more in-depth TEM techniques with a specific target/direction.

So, my next decision was to go to the Stuttgart Center for Electron Microscopy (StEM) in Germany to work on quantitative TEM imaging and spectroscopy. And there, my passion in quantification with better accuracy, precision and efficiency drove me to join Prof. Paul Voyles’ group at the University of Wisconsin-Madison to work on a project that had collaborations with researchers from different professional backgrounds. And so on.

What exactly do you mean when you say that you wanted quantitative and profound knowledge?

We say quantitative in comparison to qualitative. For example, in a HAADF STEM image, if we see a higher intensity at one atom column position than the others, we know qualitatively that there are more atoms or heavier elements there. But quantitatively, how many more? Which heavier elements? We need to learn and develop techniques to answer with ultimate accuracy and precision.

Besides, modern TEM instruments have enabled the integration of various TEM techniques, and synchronized material processes. They provide the possibility of providing profound information, including structure, chemical bonding, chemical or physical processes, properties and so on, which is far beyond former possibilities.

What drives you to achieve accuracy and precision?

Well, accuracy and precision are very important in scientific research. They directly determine the reliability of our scientific data. Meanwhile, personally, I’m a person with strong curiosity and am easily self-motivated by challenges. The target of knowing quantitative information from TEM data is not as easy as it might seem. It has a lot of challenges. To complete it, I need to learn from, and collaborate with, a lot of scientists from different backgrounds, such as data scientists, material scientists etc, and, of course, professional microscopists.

Why do you think collaboration between scientists from different fields is so important?

I think it brings us opportunities now and then. We can’t be experts in all areas. Technology advances so fast. If we work together, then other experts could solve the problem you stumbled upon without striking a blow. Beyond that, you can also see more possibilities through the collaborations. Such collaborative research challenges, helps and inspires me from time to time.

When did you first come into contact with DENSsolutions?

It was during an in-situ workshop in Hamburg in 2014 where I met the VP of Business Development, Dr. Qiang Xu. He introduced me to the Wildfire heating system and DENSsolutions’ visions and ambitions in the in-situ world. I read a lot of literature about in-situ TEM starting from my master time and had done some heating/cooling experiments using the old traditional copper grids before I met Qiang. So, the low drift and precise control of  DENSsolutions’ Wildfire system really blew me away at that time. It was a very impressive and inspiring discussion. .

How did you decide to switch from academia to a company and why did you choose DENSsolutions?

I actually wanted to step further into in-situ for some years. This feeling grows as my expertise in quantitative TEM improves. This might sound weird because a lot of people will tell you it is difficult/impossible to be precise/quantitative in in-situ worlds. But I really got depressed when coming to collaborators with quantitative TEM data and being told it was difficult to correlate it with their interests. I know it is not easy for the lab world to replicate the real world, which makes direct correlation between these two worlds less convincing or just impossible.

So I believe any effort in narrowing these two worlds makes sense for lab work to really contribute to real-world science and, eventually, applications. I want to see how these points improve as technology advances. In short, I want to bridge the lab world and real world with the pursuit of accuracy, precision and, ideally, also quantifications to make my devotion to scientific research more meaningful to human society.

For me, the visions and expectations of DENSsolutions’ vacant position in in-situ science attracted me to DENSsolutions, and then the switch from academia to industry happened as it came.  DENSsolutions has impressed me a lot in the past few years. It’s not only because of the overall capability of their products, but more importantly, the detailed features, parameters, and high level of scientific support to customers they keep pursuing. From my talks with people inside and outside the company, I got the idea that DENSsolutions has an excellent grasp of its area. The solutions they provide really touch the key concerns of scientific researchers. In short, the consensus in in-situ science with DENSsolutions and the belief in my own scientific curiosities and pursuits led me to join DENSsolutions.

I believe that by working at DENSsolutions I can benefit in seeing more possibilities of my former expertise and extend my scientific vision and possibilities. I would also be happy to communicate with the wider community to share each other’s knowledge, experiences and expertise.

You can only be innovative and successful in a high tech field like in-situ TEM if you have a great team. At DENSsolutions we constantly look out for new talent to increase our application expertise. That is why we are very happy that Dr. Dan Zhou, who did her PhD study and second postdoctoral research at the Stuttgart Center for Electron Microscopy (StEM) in Max-Planck Institute for Solid State Research in Stuttgart, Germany, decided to join us.

We interviewed her to learn more about her history, her drive and passion for electron microscopy, and her choice of DENSsolutions.

When did you fall in love with TEM (transmission electron microscopy)?

It started from the last year of my undergraduate study when I was working with SEM (scanning electron microscopy). At that time, the more profound information with much higher spatial resolution from TEM gradually attracted more and more of my interest.

How did you get to know more about TEM?

I started my graduate studies with the basics of electron optics and general TEM techniques at Trinity College Dublin in Ireland. I did some research on different nanomaterials with the basic TEM techniques I had learned, and there I realized I wanted to pursue more in-depth TEM techniques with a specific target/direction.

So, my next decision was to go to the Stuttgart Center for Electron Microscopy (StEM) in Germany to work on quantitative TEM imaging and spectroscopy. And there, my passion in quantification with better accuracy, precision and efficiency drove me to join Prof. Paul Voyles’ group at the University of Wisconsin-Madison to work on a project that had collaborations with researchers from different professional backgrounds. And so on.

What exactly do you mean when you say that you wanted quantitative and profound knowledge?

We say quantitative in comparison to qualitative. For example, in a HAADF STEM image, if we see a higher intensity at one atom column position than the others, we know qualitatively that there are more atoms or heavier elements there. But quantitatively, how many more? Which heavier elements? We need to learn and develop techniques to answer with ultimate accuracy and precision.

Besides, modern TEM instruments have enabled the integration of various TEM techniques, and synchronized material processes. They provide the possibility of providing profound information, including structure, chemical bonding, chemical or physical processes, properties and so on, which is far beyond former possibilities.

What drives you to achieve accuracy and precision?

Well, accuracy and precision are very important in scientific research. They directly determine the reliability of our scientific data. Meanwhile, personally, I’m a person with strong curiosity and am easily self-motivated by challenges. The target of knowing quantitative information from TEM data is not as easy as it might seem. It has a lot of challenges. To complete it, I need to learn from, and collaborate with, a lot of scientists from different backgrounds, such as data scientists, material scientists etc, and, of course, professional microscopists.

Why do you think collaboration between scientists from different fields is so important?

I think it brings us opportunities now and then. We can’t be experts in all areas. Technology advances so fast. If we work together, then other experts could solve the problem you stumbled upon without striking a blow. Beyond that, you can also see more possibilities through the collaborations. Such collaborative research challenges, helps and inspires me from time to time.

When did you first come into contact with DENSsolutions?

It was during an in-situ workshop in Hamburg in 2014 where I met the VP of Business Development, Dr. Qiang Xu. He introduced me to the Wildfire heating system and DENSsolutions’ visions and ambitions in the in-situ world. I read a lot of literature about in-situ TEM starting from my master time and had done some heating/cooling experiments using the old traditional copper grids before I met Qiang. So, the low drift and precise control of  DENSsolutions’ Wildfire system really blew me away at that time. It was a very impressive and inspiring discussion. .

How did you decide to switch from academia to a company and why did you choose DENSsolutions?

I actually wanted to step further into in-situ for some years. This feeling grows as my expertise in quantitative TEM improves. This might sound weird because a lot of people will tell you it is difficult/impossible to be precise/quantitative in in-situ worlds. But I really got depressed when coming to collaborators with quantitative TEM data and being told it was difficult to correlate it with their interests. I know it is not easy for the lab world to replicate the real world, which makes direct correlation between these two worlds less convincing or just impossible.

So I believe any effort in narrowing these two worlds makes sense for lab work to really contribute to real-world science and, eventually, applications. I want to see how these points improve as technology advances. In short, I want to bridge the lab world and real world with the pursuit of accuracy, precision and, ideally, also quantifications to make my devotion to scientific research more meaningful to human society.

For me, the visions and expectations of DENSsolutions’ vacant position in in-situ science attracted me to DENSsolutions, and then the switch from academia to industry happened as it came.  DENSsolutions has impressed me a lot in the past few years. It’s not only because of the overall capability of their products, but more importantly, the detailed features, parameters, and high level of scientific support to customers they keep pursuing. From my talks with people inside and outside the company, I got the idea that DENSsolutions has an excellent grasp of its area. The solutions they provide really touch the key concerns of scientific researchers. In short, the consensus in in-situ science with DENSsolutions and the belief in my own scientific curiosities and pursuits led me to join DENSsolutions.

I believe that by working at DENSsolutions I can benefit in seeing more possibilities of my former expertise and extend my scientific vision and possibilities. I would also be happy to communicate with the wider community to share each other’s knowledge, experiences and expertise.

New Catalyst Climate Publication – ‘Capturing the Intermediate’

Intermetallics with controlled microstructure and chemical composition afford unique catalytic properties, and thus are greatly desirable for heterogeneous catalysis. Identifying the key elementary steps of intermetallic process is a key step towards mechanistic understanding and clarification.

Through the using of ideal materials, e.g., single crystalline, or reaction conditions, e.g., ultrahigh vacuum, substantial progress has been made to understand the intermetallic details, nevertheless, such material or chemical environment gap hinders insightful understanding of the real intermetallic process.

Taking the advantages of real-world pressure, gas and heating environment provided by the Climate in situ gas&heating solution, Prof. Bingsen Zhang and Prof. Dangsheng Su from Institute of Metal Research, Chinese Academy of Sciences, Prof. Wei Zhang from Jilin University and Dr. Xi Liu from Synfuels China Technology Co., Ltd., studied the details about nanoscale/atomic scale microstructure- and composition-evolution of PdZn intermetallic nanoparticles under H2 atmosphere and at elevated temperatures. They revealed the sequence of the phase transitions from Pd to PdZn via the intermediate PdHx under hydrogen atmosphere. The ability of capturing the intermediate state during the reaction condition not only discloses the microstructural information in reference to the catalyst activation in details, but also sheds light on rational design and optimum synthesis of intermetallic compound catalysts.

Related results have been accepted for publication in Angewandte Chemie International Edition.

https://onlinelibrary.wiley.com/doi/10.1002/anie.201812292

Calcination Leads to Atomic Dispersion: New Climate publication in Nature Communications

Substrate-supported noble metal single-atom catalysts (SACs) are widely used in many important chemical reactions for their high activity and selectivity. However, the fabrication of high concentration of single-atom catalysts (SACs) with long-term stability remains a challenge. For example, at the working conditions, usually calcination at a high temperature, the supported SACs migrate and coarsen (a process named Ostwald ripening), resulting in a decreased catalytic performance. Writing in Nature Communications, researchers from Dalian Institute of Chemical Physics (Chinese Academy of Sciences) and Tianjin University of Technology, found that the high- temperature calcination of Pt nanoparticles on reductive Fe 2 O 3 substrate in air is favorable for the formation of high concentrations of thermally stable Pt SACs, which is different from the traditional Ostwald ripening. By employing the Climate in situ gas & heating solution and HAADF-STEM imaging, they directly observed the disintegration of Pt nanoparticles at 800 °C under a flow of 1 bar O 2 . During the in- situ reaction process, they found particle disappearance occurs in the absence coalescence, implying the genesis of atomically-dispersed Pt entities. The in-situ results are in good agreement with the ex-situ characterizations and theoretical calculations. The new findings provide a new route to fabricate high-metal-loading and thermal stable SACs for a wide range of industrially important catalytic reactions.

Happy Holidays

Our home-grown dendritic decorations wish you happy holidays and a prosperous 2019

Counting atoms in operando conditions

The efficiency of a catalyst relies on the capability of promoting reactions directly on its surface. Thus, there have been many attempts to accurately determine the atomic structure at the surface when gasses are flown on the catalytic sample.

Obviously, in situ electron microscopy is the best candidate to provide that answer, due to the possibility of recording ultra high resolution information while flowing gasses on the sample at high temperature. However, due to the nature of the imaging process, only 2D projections can be captured, severely limiting our understanding of the catalytic process.

Researchers at EMAT, Antwerp, have combined the high stability of the Climate in situ gas&heating solution with their multi-year experience on developing algorithms to accurately retrieve 3D structures down to atomic resolution. Platinum nanoparticles were cyclically exposed to reducing and oxidizing gas mixtures to promote and study surface re-faceting; after each step, high resolution STEM images were acquired and they were analyzed by means of a novel methodology based on deep convolutional neural networks (CNN) and molecular dynamics simulations.

 

The results show that it is now possible to obtain very accurate 3D atomic models that enable researchers to “see and count” atoms which are sitting on the surface. These new findings will allow a much deeper characterization and understanding of the processes behind catalytic reactions.

Does fluidic control matter?

In situ liquid experiment featuring Copper deposition

It can be seen that high flow rates (1200 nl/min) promote plating of the electrode. However, when switching to lower flow rate values (50 nl/min) the growth mechanism changes and dendrites appear.

The pressure-based liquid pump, the absence of dead volumes and the defined liquid channel all contribute to a very responsive system that allows to accurately vary experimental conditions within seconds.