DENSsolutions has installed yet another Stream system in Germany at Forschungszentrum Jülich

DENSsolutions has installed yet another Stream system in Germany at Forschungszentrum Jülich

DENSsolutions Installing South Korea's second Stream system at Seoul National University

From left to right: Andreas Körner and Dr. Andreas Hutzler

We are proud to announce that DENSsolutions has installed yet another Stream system in Germany at the esteemed Forschungszentrum Jülich, one of the largest interdisciplinary research centres in Europe. In this article, we interview Dr. Andreas Hutzler, the new head of the TEM lab in the Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN) at Forschungszentrum Jülich, to learn more about their advanced microscopy facility, its research direction, as well as how our Stream system is advancing their research.

Can you tell me more about the microscopy facility at HI ERN?

“The Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN) is part of the Forschungszentrum Jülich. It specializes in providing crucial research on technologies needed to utilize renewable energies in the decades to come. Our research is centered around fuel cells, electrolyzers and hydrogen storage. The institute was founded in 2013 and has been growing ever since. In 2021, its new research building was inaugurated, hosting the space for a new transmission electron microscope, the Talos F200i from Thermo Fisher Scientific. This tool provides in-house structural analysis on the nanoscale for catalysts, support systems and membranes.”

What type of applications are the users at HI ERN using the Stream system for?

“Our goal is to study electrochemical processes taking place on electrode and catalyst surfaces within electrolyzers and fuel cells down to the atomic scale. We aim to understand which reactions take place, and which conditions enhance the performance of the cells or disintegrate the structures involved.

In order to understand this, we consider beam-induced effects onto the solution chemistry we investigate. For this, we utilize a comprehensive radiolysis model for unraveling the influence of electron irradiation onto the sample and compare the results to non-biased experimental observations. Once this is understood, we continue with analyzing dynamic processes at the nanoscale to gain insights into reaction pathways and degradation mechanisms in P2X and X2P applications.”

What particular features of the DENSsolutions Stream solution attracted you to the system?

“In order to understand observable processes and their correlated chemistry, it is necessary to accurately tune experimental conditions while operating the system. The ability of the Stream system to flexibly adjust pressure, flux, temperature and potential allows to run a manifold of experiments in a wide parameter space. This is needed in order to verify the stability of our reaction kinetic models and for testing electrolysis at borderline conditions. Before, the structures could only be studied after the reaction has taken place. But the ability to directly observe dynamic processes on-site in real time gives valuable insights in the chemistry at hand.”

Can you tell me about the grant that was won to acquire the system?

“One of our key research interests is the development of new methods for characterizing fundamental and applied processes in electrocatalysis relevant to electrochemical energy conversion. After establishing identical-location TEM (IL-TEM) for energy applications and with the start of my team, a new transmission electron microscope as well as equipment needed for in situ liquid-phase TEM was funded by and installed at HI ERN. This particular toolbox will be a great asset for the nanoanalysis of electrochemical processes in my team which will enable unique insights in energy research.”

In your experience so far, how have you found the Stream system?

“The modular architecture of the Stream system enables a very versatile applicability without risking leakage or cross-contaminations. The performance of LP-TEM is considerably enhanced due to the controllability of liquid flow, the ever-present window bulging via the utilization of a novel chip design as well as a differential pumping system as a standard. Moreover, DENSsolutions came forward with providing non-standard solutions in order to provide compatibility with other setups at our institute.”

DENSsolutions Prof. Jungwon Park
Dr. Andreas Hutzler
Head of the Transmission Electron Microscopy lab| HI ERN, Forschungszentrum Jülich

Dr. Andreas Hutzler is the new head of the Transmission Electron Microscopy lab at HI ERN, PI of multiple projects at HI ERN and university and is currently setting up a team for nanoanalysis of electrochemical processes. His research interests mainly focus on methodological aspects of LP-TEM and its application in electrochemical energy conversion.

Discover Dr. Andreas Hutzler’s publications:

Learn more about Stream:

Discover publications made possible by Stream:

Subscribe to our newsletter to stay up-to-date with the latest in situ microscopy news.

Climate helps uncover phase coexistence and structural dynamics of redox metal catalysts

Climate helps uncover phase coexistence and structural dynamics of redox metal catalysts

Using our Climate system, scientists are able to interrelate the atomic-scale structural dynamics of redox metal catalysts to their activity.

Original article by Xing Huang, Travis Jones, Alexey Fedorov, Ramzi Farra, Christophe Copéret, Robert Schlögl, and Marc-Georg Willinger

Marc Willinger TOC 1200x628

Metal catalysts have been extensively studied due to their critical role in industrial redox reactions. However, many gaps in research still remain, hampering the optimization of their design. Specifically, the behavior of metal catalysts under operating conditions and the relationship between structural dynamics and catalytic activity are still not fully understood. Indeed, an atomistic comprehension of the structure–activity relationship of working catalysts is essential for the optimization of their design. 

In their recently published paper, Dr. Marc-Georg Willinger from ETH Zurich, Dr. Xing Huang from Fuzhou University and fellow collaborators from the Fritz-Haber Institute of Max-Planck Society and the Max Planck Institute for Chemical Energy Conversion explore the phase coexistence and structural dynamics of redox metal catalysts. Using our Climate system, the researchers are able to achieve controlled gas-flow and imaging, obtaining atomic-level insights into the correlation between the structural and chemical dynamics and catalytic function. In light of today’s environmental challenges, the development of improved catalysts for more resource-efficient processes is becoming increasingly critical. Importantly, developing improved catalysts requires their direct observation during operating conditions. In this work, the authors have obtained atomic-scale insights into catalyst dynamics in various relevant redox reactions.

Redox reactions

Copper is a popular transition metal used as an active component in redox catalysts for many reactions, including CO₂ reduction and water gas shift reaction (WGSR). However, an atomistic description of the state of copper under redox conditions in these catalysts remains unrealized. In this publication, Dr. Willinger and his fellow collaborators present a detailed, high-resolution study of copper during the hydrogen oxidation reaction (HOR), revealing fundamentals of catalyst dynamics under reactive conditions. Beyond the elementary hydrogen oxidation reaction, the researchers extend the observed dynamic behavior to more relevant redox reactions and other metal catalysts. Specifically, they explore the redox dynamics of copper and palladium in the active state during methanol oxidation and methane oxidation reactions, respectively.

Hydrogen oxidation reaction on copper

Studying HOR offers the opportunity to obtain detailed atomistic insights into the reaction between the catalyst and the gas phase. HOR was chosen because it is the most elementary redox reaction and yields only water as a product, thereby reducing the complexity related to potential electron-beam-induced processes. In this study, the researchers systematically assess the effects of temperature and gas-phase conditions. Moreover, they explore how the chemical potential of the gas phase defines the phase, size, and shape of catalyst particles, driving the system into a nonequilibrium dynamic state during catalysis. Due to the simultaneous detection of catalytic conversion, they are able to relate directly the observed dynamics and surface structures to catalytic activity. 

1) Redox dynamics and structural analysis of Cu

Copper nanoparticles of 50–200 nm were first loaded in the Climate Nano-Reactor. In situ TEM images of the copper nanoparticles were then recorded. It was found that the particles exhibit rich structural dynamics, which are associated with reconstruction and random motion, as well as particle sintering and red-ox induced splitting. The figure (A–L) and movie below depict these structural dynamics. Shown in M) is the integrated SAED pattern and corresponding radial intensity profile. The in situ SAED revealed dynamically appearing and disappearing diffraction spots, and confirmed the presence of metallic copper and Cu₂O as the sole oxide phase. The constant competition between oxide growth and reduction are reflected in the in situ SAED and the observed structural dynamics. Indeed, the structural dynamics are a consequence of chemical dynamics, characterized by phase coexistence and continuous interconversion between Cu⁰ and Cu₂O. The high-resolution imaging in Figure 1N) confirms this, showing a metallic head coherently interfacing with an oxide tail.

Figure 2: Marc Willinger

Figure 1: The redox dynamics and structural analysis of Cu. A–L) show the in situ TEM observations of catalyst reshaping (A–D), sintering (E–H), and splitting (I–L). In M) the integrated SAED pattern and corresponding radial intensity profile are shown. N) shows the HRTEM image of a nanoparticle containing a metallic head coherently interfacing with an oxide tail.

Movie 1: The redox dynamics of copper showing catalyst reshaping, sintering and splitting.

2) Effects of temperature and gas-phase composition

The authors then sought out to explore the effect of temperature on the observed redox dynamics. First, the temperature was decreased from 500 to 300°C, while maintaining a H₂/O₂ ratio of 10/1. During the temperature decrease, the researchers observed the growth of oxide dendrites, which reflects the increasing oxidation potential. Simultaneously, due to the slower kinetics of the redox reaction at lower temperatures, a reduction of the structural dynamics was observed. During heating from 300 to 750 °C, the system passes through a regime of increased dynamics (550 °C) that are characterized by translational motion and restructuring due to oxide growth and reduction, until it finally reaches a state that is less dynamic and dominated by metallic copper at 750°C. This is shown in the figure below (A–D). The reconstructed HRTEM images taken at 300 and 750°C are shown in 2E) and 2F), respectively. Next, integral SAED (Figure 2G,H) was performed to investigate phase analysis, revealing the relation between phase composition and temperature. It has been previously demonstrated that the trend in the oxide content reflects the decreasing chemical potential of oxygen with increasing temperature. However, the authors observe a notable exception of this general trend at around 550 °C, which is mostly due to the effect of water that is produced at substantial rate and contributes to the redox dynamics.

Figure 2: Marc Willinger

Figure 2: Chemical potential versus structural dynamics of Cu. A–D) In situ TEM observation of dynamics at 300–750 °C and a H₂/O₂ ratio of 10/1. E,F) show the reconstructed HRTEM images taken at 300 and 750 °C. G) and H) show the normalized radial profiles extracted from the integrated SAED patterns and subsequent radial intensity profile, respectively. I–L) In situ observation of copper dynamics during decreasing H₂/O₂ ratio from 10/1 to 5/1 at 500 °C.

Next, the researchers explored the influence of gas-phase composition on the structural dynamics, gradually decreasing the H₂/O₂ ratio from 10/1 to 5/1 at 500 °C. It was found that the relative increase of the oxygen partial pressure leads to a transformation of initially spherical nanoparticles into elongated particles with a head–tail structure. This is depicted in Figure 2I–L above. At the same time, the average particle size declines due to an increased rate of particle splitting, until a new size regime and dynamic equilibrium is established. Conclusively, the real-time observations under varying gas-phase composition and temperature show a clear effect of the gas-phase chemical potential on the average particle size. The in situ observations show clearly that redox dynamics make particles mobile, thereby considerably increasing the rate of sintering as compared to thermal sintering; yet the sintering under redox conditions is balanced by particle splitting, such that a certain size distribution is established as a function of reaction conditions.

“Controlled gas-flow and imaging – coupled with on-line mass spectroscopic analysis of the gas-phase composition as enabled by the Climate system – is essential for studies on the behavior of active catalyst and allows us to correlate observed structural and chemical dynamics to catalytic function.” – Dr. Marc-Georg Willinger, ETH Zurich

3) Relation between structural dynamics and catalytic activity

After investigating the gas-phase and temperature-induced dynamic processes, the researchers then sought out to explore the relationship between the observed structural dynamics and catalytic activity. The MS data is presented in Figure 3A) below, showing the formation of water and simultaneous consumption of oxygen. This ultimately confirms the catalytic activity of copper. A notable increase in water production and oxygen consumption is observed between 500 and 600°C, which is also the same range in which the intense structural dynamics occurred. In Figure 3B–D), the sequential HRTEM images of particle reshaping/restructuring at 550°C is presented (H₂/O₂ ratio of 10/1). This is also shown in the movie below. Although challenging, the researchers were still able to capture the thin oxide monolayer existing on the surface of the metallic portion of the particles (see Figure 3E,F). Interestingly, the surface oxide layer is observed even at 750°C. The structural features of the monolayer oxide imaged on various facets can be observed in Figure 3G,H).

Figure 3: Marc Willinger

Figure 3: Relation between structural dynamics of Cu and catalytic activity. A) shows the MS data collected at varied temperatures. B–D) show the sequential HRTEM images of particle reshaping/restructuring at 550°C. E,F) show the enlarged HRTEM images of the areas indicated by dashed rectangles in (B) and (D). G) shows an HRTEM image, and in H) an enlarged HRTEM image of the area indicated by the dotted rectangle in (G).

Movie 2: HRTEM movie showing particle reshaping and restructuring at 550°C

Methanol oxidation reaction on copper

After investigating the particle dynamics for hydrogen oxidation on copper, the researchers then set out to assess the generality of the phenomena described above. They first investigated the state of copper under conditions of methanol oxidation, a catalytic reaction that is relevant to industrial synthesis of formaldehyde. The figure below shows in situ TEM images of copper nanoparticles recorded at 600 and 500°C (Figure 4A–C and 4E–G), respectively. The dynamic behavior observed involves reshaping, sintering, and splitting of particles, similar to what was observed in the case of hydrogen oxidation. A shift to a more oxidized state with decreasing temperature was observed and verified by in situ SAED (Figure 4D,H). The redox dynamics are most pronounced at around 500°C under the chosen 1:1 ratio of MeOH and O₂.

Figure 4: Marc Willinger

Figure 4: Structural dynamics of Cu in methanol oxidation reaction. A–H) show TEM images and SAED patterns of Cu recorded in situ during methanol oxidation at 600 °C (A–D) and at 500 °C (E–H), respectively.

Methane oxidation reaction on palladium

Next, they investigated methane oxidation on palladium, a transition metal that is much harder to oxidize than copper. In the figure below, the structural dynamics related to catalytic activity in methane oxidation on palladium is presented. As in the case of copper, structural dynamics evolve when palladium is driven toward the Pd/PdO phase boundary. In an ~2:1 ratio of CH₄ and O₂, the catalyst remains relatively static at 350°C and shows coexistence of Pd and PdO as evinced by the in situ SAED. The system evolves to a highly dynamic state at 550°C. The MS data recorded simultaneously with TEM observation reveal a pronounced formation of CO₂ and consumption of CH₄ and O₂ under these conditions (see Figure 5I).

Figure 4: Marc Willinger

Figure 5: Structural dynamics related to catalytic activity in methane oxidation on Pd. A–H) In situ TEM images and SAED patterns of Pd recorded during methane oxidation at 350°C (A–D) and 550°C (E–H), respectively. I) shows the MS data recorded during in situ TEM observation of Pd in methane oxidation.

Conclusion

Via the above in situ studies of copper and palladium catalysts using our Climate system, the researchers show that catalytic activity goes hand-in-hand with redox processes of the metal catalyst. This paper evinces that the associated dynamics sensitively depend on reaction temperature and gas-phase composition. Importantly, only direct observation could reveal the interplay between metal and oxide phases and relate it to the onset of catalytic activity. This is precisely where our advanced in situ solutions come into play, enabling the direct observation of phenomena while it occurs. We are proud of the role that our Climate system has played in making this research possible and strive to continue enabling groundbreaking research in the future.

Hanglong Wu portrait

“The DENSsolutions Climate System allows us to reveal the so-far unseen: Looking at not only how the gas-phase is changed in the presence of a catalyst, but also studying how the interaction between gas-phase and catalyst leads to the emergence of catalytic function. Direct real-space observation is essential for our understanding of working catalysts and the development of new processes that are urgently needed in view of climate change and limited natural resources.”

Dr. Marc-Georg Willinger
Group Leader |  ETH Zurich

Original article:

Discover our Climate solution:

Discover more publications made possible by Climate:

DENSsolutions Climate system takes home the microscopy today 2021 innovation award

DENSsolutions’ Climate system takes home the Microscopy Today 2021 Innovation Award

DENSsolutions becomes a consecutive two-time winner of the Microscopy Today Innovation Awards. This year, our Climate system is recognized as one of the 10 most game-changing microscopy innovations of 2021.

Subscribe to our newsletter to stay up-to-date with the latest in situ microscopy news.

DENSsolutions’ Climate system takes home the Microscopy Today 2021 Innovation Award

DENSsolutions’ Climate system takes home the Microscopy Today 2021 Innovation Award

DENSsolutions becomes a consecutive two-time winner of the Microscopy Today Innovation Awards. This year, our Climate system is recognized as one of the 10 most game-changing microscopy innovations of 2021.

Just last year, our Stream system was awarded the Microscopy Today Innovation Award for its unique contribution to the field of liquid phase electron microscopy. We are honored to be taking home the same award for a second year in a row but this time for the remarkable innovation that is our Climate system. Climate is recognized as one of the 10 most game-changing microscopy innovations in 2021 by Microscopy Society of America‘s esteemed magazine, Microscopy Today. We interviewed our Chief Technology Officer Dr. Hugo Pérez-Garza, who led the development of the Climate system, to learn all about the unique benefits that made it earn such an esteemed award, as well as the development process and Climate’s current and envisioned applications. The transcript of the interview is provided below.

What was your reaction when you first heard the news?

It was pretty exciting. As you can imagine, the entire team was very happy when we first heard the news. At the end of the day, I think that this is just another consequence of the amazing teamwork that prevails in this company. And of course, to be accredited by the MSA is a big honor, especially as this is a highly esteemed award within the community. So it really means a lot to us. We really feel confident that our technology, and particularly our Climate system, will help scientists explore all sorts of new research possibilities.

What unique aspects of the system do you think made it earn such an esteemed award?

Over the last months, we have been exerting a lot of effort into making sure that we can improve the Climate system from various different angles. So that means that we have been doing a lot of work to ensure that we can optimize the different components that make up this plug-and-play system. Specifically, we have been trying to boost our MEMS capabilities (the Nano-Reactor). Moreover, we have been trying to continuously improve our hardware components, including the Gas Supply System, the Vaporizer, the Mass Spectrometer, etc. And of course, making sure that we can have new solutions as well for the software platform. Now when you put all these together, what we ended up realizing was that this new optimized Climate system brings all sort of real unique aspects to one’s research.

1) Live gas mixing

Firstly, Climate offers the possibility of performing live gas mixing (i.e. making sure that you can achieve any desired gas composition instantaneously). It ensures that users won’t have to wait for their gas mixtures to be prepared. We see this big added value in our customers’ experiments, for example in redox reactions, where the intrinsic nature of the experiment demands the possibility to quickly go from an oxidizing environment to a reducing environment. Often times people have to do this back-and-forth and in a fast and repetitive way. 

2) Start a new experiment (from a dry to wet environment or vice versa) within minutes

Furthermore, for these experiments a lot of researchers would be interested in humidifying the gas composition. This is precisely where the Vaporizer comes in. Now what happens here is that when you are humidifying the gas, often people are afraid of the contamination that the water molecules would represent for the gas lines. And that is why systems have to baked or have to undergo lengthy pumping times. But that wouldn’t be the case with the Vaporizer, as we have designed it in such a way that the introduction of the water vapor to the gas mixture is the last thing before entering the holder. So that ensures that your Gas Supply System will remain clean, and that you don’t have to perform these baking procedures or keep it pumping over night. This ultimately means you can go from a dry environment to a wet environment, or vice versa, in just a few minutes. So it opens up a lot of possibilities because it gives users this flexibility. 

3) Safely work with explosive mixtures and independently control gas parameters

The fact that we’re dealing with extremely low volumes of gas also means that we can safely handle explosive mixtures even if you plan to do this under extreme conditions such as high temperatures (above 1000°C) in combination with high pressures (i.e. 2 bars) and high relative humidity (i.e. 100%). Not only can you safely handle these explosive mixtures, but you can also control the relative humidity independently from other parameters such as temperature, pressure, gas composition and flow rate. So having this independent control also brings a lot of flexibility to users. 

4) Perform real nano-calorimetry and calibrate for time delay

The Nano-Reactor is also something very unique as we have been heavily optimizing the design such that, for example, the microheater allows for real nano-calorimetry. And this is really unique because it means that you can start quantifying and measuring the tiniest changes in temperature dissipation to understand if you’re observing an exothermic or endothermic reaction. And this is also really beneficial because you can calibrate for time delay, which is an issue that systems usually suffer from due to the unavoidable delay from the Gas Supply System to the MEMS device and to the Mass Spectrometer. Now, we can calibrate for that. 

5)  Prevent bypasses and achieve a desirable SNR

Moreover, the unique design of the Nano-Reactor itself, for which we have a patent, ensures that we can have an on-chip inlet and outlet. In other words, we can ensure that the gas will flow from the inlet to the outlet via the region of interest in a uni-directional way. And that means we can prevent bypasses and therefore improve the signal-to-noise ratio and the sensitivity of the Gas Analyzer. So the combination of these offerings (for example that our MEMS device can go to these high pressures like 2 bar, or allow you to perform EDS experiments well above 900 degrees at high pressures) ends up bringing a very unique value proposition for the user. 

What unique aspects of the system do you think made it earn such an esteemed award?

Over the last months, we have been exerting a lot of effort into making sure that we can improve the Climate system from various different angles. So that means that we have been doing a lot of work to ensure that we can optimize the different components that make up this plug-and-play system. Specifically, we have been trying to boost our MEMS capabilities (the Nano-Reactor). Moreover, we have been trying to continuously improve our hardware components, including the Gas Supply System, the Vaporizer, the Mass Spectrometer, etc. And of course, making sure that we can have new solutions as well for the software platform. Now when you put all these together, what we ended up realizing was that this new optimized Climate system brings all sort of real unique aspects to one’s research.

1) Live gas mixing

Firstly, Climate offers the possibility of performing live gas mixing (i.e. making sure that you can achieve any desired gas composition instantaneously). It ensures that users won’t have to wait for their gas mixtures to be prepared. We see this big added value in our customers’ experiments, for example in redox reactions, where the intrinsic nature of the experiment demands the possibility to quickly go from an oxidizing environment to a reducing environment. Often times people have to do this back-and-forth and in a fast and repetitive way. 

2) Start a new experiment (from a dry to wet environment or vice versa) within minutes

Furthermore, for these experiments a lot of researchers would be interested in humidifying the gas composition. This is precisely where the Vaporizer comes in. Now what happens here is that when you are humidifying the gas, often people are afraid of the contamination that the water molecules would represent for the gas lines. And that is why systems have to baked or have to undergo lengthy pumping times. But that wouldn’t be the case with the Vaporizer, as we have designed it in such a way that the introduction of the water vapor to the gas mixture is the last thing before entering the holder. So that ensures that your Gas Supply System will remain clean, and that you don’t have to perform these baking procedures or keep it pumping over night. This ultimately means you can go from a dry environment to a wet environment, or vice versa, in just a few minutes. So it opens up a lot of possibilities because it gives users this flexibility. 

3) Safely work with explosive mixtures and independently control gas parameters

The fact that we’re dealing with extremely low volumes of gas also means that we can safely handle explosive mixtures even if you plan to do this under extreme conditions such as high temperatures (above 1000°C) in combination with high pressures (i.e. 2 bars) and high relative humidity (i.e. 100%). Not only can you safely handle these explosive mixtures, but you can also control the relative humidity independently from other parameters such as temperature, pressure, gas composition and flow rate. So having this independent control also brings a lot of flexibility to users. 

4) Perform real nano-calorimetry and calibrate for time delay

The Nano-Reactor is also something very unique as we have been heavily optimizing the design such that, for example, the microheater allows for real nano-calorimetry. And this is really unique because it means that you can start quantifying and measuring the tiniest changes in temperature dissipation to understand if you’re observing an exothermic or endothermic reaction. And this is also really beneficial because you can calibrate for time delay, which is an issue that systems usually suffer from due to the unavoidable delay from the Gas Supply System to the MEMS device and to the Mass Spectrometer. Now, we can calibrate for that. 

5)  Prevent bypasses and achieve a desirable SNR

Moreover, the unique design of the Nano-Reactor itself, for which we have a patent, ensures that we can have an on-chip inlet and outlet. In other words, we can ensure that the gas will flow from the inlet to the outlet via the region of interest in a uni-directional way. And that means we can prevent bypasses and therefore improve the signal-to-noise ratio and the sensitivity of the Gas Analyzer. So the combination of these offerings (for example that our MEMS device can go to these high pressures like 2 bar, or allow you to perform EDS experiments well above 900 degrees at high pressures) ends up bringing a very unique value proposition for the user. 

What inspired you and the entire team to develop Climate in the first place?

Certainly understanding the importance and the impact that environmental studies can have on our global society was a big source of inspiration for the entire team. Having said that, understanding the solid-gas interactions at the nanoscale is what sets the foundation such that scientists can really start understanding how to optimize and synthesize future catalytic nanoparticles, which will end up playing a crucial role in applications such as carbon capture, energy storage and conversion as well as food production. So it is really this profound information that we can get from in situ TEM that gives this understanding. Because when you can start correlating particle size with composition, crystal orientation, or with the atomic or the electronic structure, it really gives a deep level of understanding for all these kinds of experiments. 

Can you walk us through the development process of Climate?

It has been 5 or 6 years since we launched our first product line for in situ gas analysis. Ever since, what we have been doing is trying to make sure that we can stay as close as we can to our customers as well as prospects. Now the intention of doing that is when you start gathering the feedback and the vision that both groups have, you start understanding the pain points a little bit more. You start becoming more empathic to their experimental needs. And that helps us identify the product profile that we should have in place. And when you are aware of this product profile, then automatically you know what technologies must be developed, which is part of your roadmap. And subsequently when you have that in place, then you also know what people and processes must be involved. So, it’s a matter of doing that so that when we gather these market requirements, we can follow a defined product creation process that will allow us to develop a technology that will match these market requirements. 

What future applications do you envision for Climate?

Certainly everything related to green technologies. As I mentioned earlier, that is a big goal and motivation that we all have at this company. So these kinds of experiments and topics I was referring to like carbon capture, energy conversion and storage, and all sort of environmental protection kind of studies, that’s really where everything will head towards. 

Thank you for reading. To learn more about our Climate system please follow the links below.

Download the Climate brochure: 

See a customer publication:

Receive a quotation:

Receive a demo:

Subscribe to our newsletter to stay up-to-date with the latest in situ microscopy news.

Scientists develop a powerful distributed electron microscopy technique to study complex reactions in solution

Scientists develop a powerful distributed electron microscopy technique to study complex reactions in solution

Using our Ocean system, scientists demonstrate the power of combining multiple electron microscopy methods, showing for the first time how the desilication mechanism of zeolite crystals proceeds in 3D on the single particle level.

Original article by Hanglong Wu, Teng Li, Sai P. Maddala, Zafeiris J. Khalil, Rick R. M. Joosten, Brahim Mezari, Emiel J. M. Hensen, Gijsbertus de With, Heiner Friedrich, Jeroen A. van Bokhoven and Joseph P. Patterson
Thomas article feature image
Liquid phase electron microscopy (LPEM) possesses the potential to revolutionize materials science by providing direct evidence of processes occurring in solution at the nanoscale. However, the use of high-energy electrons can be problematic as it can significantly change the solution chemistry and the liquid sample being imaged. Therefore, a primary challenge in LPEM is understanding the role the electron beam plays in the observed mechanism. As such, researchers find themselves stuck on the same question: “Which features of the native process are being captured?”

Dr. Hanglong Wu and his colleagues from the Eindhoven University of Technology, ETH Zurich and University of California, Irvine provide a robust answer to this pressing question by developing a novel approach for studying complex reactions in solution. This concept, which they term a “distributed electron microscopy (EM) method” combines information from multiple EM methods, including LPEM, cryogenic EM and cryo-electron tomography. To demonstrate this powerful method, Dr. Wu and his colleagues use our dedicated LPEM solution to study the desilication mechanism of zeolite crystals. They show for the first time with an exceptional level of confidence how the reaction proceeds in 3D on the single particle level. Moreover, they show how LPEM can be combined with cryo-EM to study a complete reaction which is essential to rule out beam-induced effects in LPEM experiments. 

The desilication study

Dr. Wu and his colleagues employ a distributed electron microscopy method to study the desilication process in zeolite crystals, showing how the reaction proceeds in 3D and what controls the desilication kinetics. This distributed approach enables them to explore and understand the native mechanism at hand, exploiting the power of each imaging modality – LPEM, cryogenic EM (cryo-EM) and cryo-electron tomography (cryo-ET). The researchers use Al-zoned ZSM-5 zeolites, which have an aluminum-rich rim and an aluminum-poor core, as a model system, to study the desilication process. The reason this is an ideal model system is that ZSM-5 crystals have a complex 3D morphology and are also considerably beam-sensitive.

The two videos below respectively show the automated sample loading process assisted by a liquid handling machine called SciTEM, and how the desilication process was initiated via the manual flowing of an NaOH solution into the cell.

Movie 1: Movie showing the SciTEM-assisted sample loading process, where a tiny droplet (~ 300 pL) containing zeolite crystals was deposited on the centre of the viewing window area.

Movie 2: Movie showing that the liquid cell is gradually filled with 0.6 M NaOH

Using LPTEM to observe the desilication process

Using LPTEM, Dr. Wu and his colleagues monitored the desilication process of individual parent zeolite crystals in multiple areas of a single cell. In the movie below, the desilication process of three pre-etched zeolite crystals can be observed over a 3-hour period. In contrast, for the crystals without the pre-etching treatment, the researchers find that the zeolites were only partially desilicated after 30 h in the liquid cell.

Movie 3: Movie showing the desilication process of three pre-etched zeolite crystals. On the left is the raw data movie and on the right a 30-frame-averaged data movie

The LPTEM data collected by the researchers provide evidence that desilication propagates along the c-axis beginning either at the Al-rich/Si-rich interface or in the crystal center. Moreover, it is observed that for the intergrowth structures, the process begins at the intergrown interface. Importantly, the LPEM experiments show that the confinement in the liquid cell slows down the desilication kinetics and that the electron beam does in fact influence the morphological evolution. This then raises the question that Dr. Wu and his colleagues sought out to answer: which features of the native desilication process are actually being captured?

LPTEM vs. LPSTEM

The LPSTEM results (Figure 1) observed by the researchers were significantly different from the LPEM observations. Dr. Wu and his colleagues believe that the differences mainly originate from contrast formation mechanisms and the localized electron distribution of each imaging mode. On one hand, LPTEM enables the quick control of the localized low electron flux homogeneously across the field of view. However, the appearance of diffraction contrast from the defects can be problematic for quantitative contrast interpretations. On the other hand, LPSTEM enables the better understanding of sample contrast evolution due to being less affected by diffraction effects. Simultaneously, however, the focused high flux electron probe might bring localized structural changes caused by radiolysis of the sample itself and water.

Figure 1 Hanglong article11

Figure 1: Desilication process of Al-zoned ZSM-5 crystals imaged by pulsed LP-STEM. Scale bars: 200 nm.

The LPSTEM results provide evidence that desilication proceeds by a sequential two-step process. Because the STEM probe scanning accelerates the etching process, this enabled the desilication process to be visualized with apparently “native” kinetics, thereby overcoming the confinement effects in the liquid cell. However, as beam effects were observed at all applied electron doses, the question remains: which features of the native desilication process are being captured?

Using cryo-EM and cryo-ET to observe the desilication process

Monitoring the desilication process using cryo-EM was the next step for Dr. Wu and his colleagues. Unlike LPEM, cryo-EM enabled the researchers to monitor the process in the absence of confinement and electron beam effects. In practice, cryo-TEM is generally performed prior to an in situ study, as it provides key information on what intermediate structures are present and, most importantly, how they evolve statistically over time. The figure below shows the cryo-EM results presented for crystals at different time points, where the stages of desilication are in agreement with the collective LPEM data and the general sample evolution observed by cryo-EM.

Figure 2 Hanglong article

Figure 2: Desilication process of ZSM-5 zeolites monitored by cryo-TEM (a) and cryo-STEM (b). Scale bars: 200 nm.

To verify the 3D interpretation of the desilication process, cryo-ET was performed on four crystals at an intermediate state of desilication. The movie below shows the cryo-ET reconstruction of a 12-hour desilicated zeolite crystal and Figure 3 shows the corresponding segmented surface rendering of the crystal.
Figure 3 Hanglong article

Figure 3: Segmented surface rendering of the 12 h desilicated zeolite crystal.

Movie 4: Movie showing the cryo-electron tomography 3D reconstruction of a 12 h desilicated zeolite crystal

Collectively, with the cryo-EM results, Dr. Wu and his colleagues were finally able to distinguish which information provided by LPEM observations represents the native desilication and which is an artifact. The cryo-EM data supported the hypothesis from both LPTEM and LPSTEM that desilication propagates along the c-axis. Moreover, it confirmed that it should occur in a two-step process, where both processes begin at the Al-rich/Si-rich interface and propagate toward the center of the crystal. This suggests that the LPTEM data either represents an artifact caused by the electron beam, confinement within the liquid cell, the sample preparation, or that the intermediates of this process are too transient to be captured by the cryo-EM data.

Novelty in findings

This study is a major step forward in understanding the role that the electron beam plays in LPEM experiments. Ultimately the collective results reveal that the desilication mechanism of zeolite crystals occurs via a two-step anisotropic etching process. This complex mechanism was only discovered due to the novel distributed approach that Dr. Wu and his colleagues employed. Particularly, the combination of LPEM and cryo-EM was essential to rule out the effects of the electron beam in the LPEM experiments.

Considering the strength of this distributed method, Dr. Wu and his colleagues anticipate that the combination of LPEM and cryo-EM will become a standard approach for understanding reaction mechanisms in aqueous solutions and could even be extended to non-aqueous solutions. Moreover this method will enable scientists to draw robust conclusions on the 3D reaction mechanisms of other important beam-sensitive material systems, such as biomaterials and proteins, whereby some grand challenges in materials science and life sciences could be potentially solved.

Hanglong Wu portrait
“DENSsolutions offers a simple but reliable solution for us to look into materials processes in liquid at the nanoscale. Currently, it is still difficult to observe the same phenomena in different liquid cells. That’s why people always joke that each LPEM experiment is “unique”. However, using the Ocean system, we have almost made every single “unique” LPEM experiment reproducible.”
Dr. Hanglong Wu
Postdoctoral Researcher |  Eindhoven University of Technology

Original article:

Discover our LPEM solutions:

Discover more publications made possible by our LPEM solutions:

Thomas article feature image

Scientists present novel approaches to map and control liquid thickness in LPEM experiments

Using our Ocean system, scientists present new approaches to overcome the limitations in LPEM experiments by quantitatively mapping and controlling liquid layer thickness.

Subscribe to our newsletter to stay up-to-date with the latest in situ microscopy news.

Scientists present novel approaches to map and control liquid thickness in LPEM experiments

Scientists present novel approaches to map and control liquid thickness in LPEM experiments

Using our Ocean system, scientists present new approaches to overcome the limitations in LPEM experiments by quantitatively mapping and controlling liquid layer thickness.

Original article by Hanglong Wu, Hao Su, Rick R. M. Joosten, Arthur D. A. Keizer, Laura S. van Hazendonk, Maarten J. M. Wirix, Joseph P. Patterson, Jozua Laven, Gijsbertus de With, Heiner Friedrich

Thomas article feature image

Liquid phase electron microscopy (LPEM) presents itself as a fundamental technique in the monitoring of nanoscale material processes in real-time. However, there are many challenges faced by the LPEM community with regard to quantifying and controlling liquid layer thickness to achieve laboratory-scale solution conditions and high-resolution imaging.

Using our dedicated LPEM solution, Ocean, Dr. Heiner Friedrich and his team at the Eindhoven University of Technology have paved the way for the better design of LPEM experiments and improved control of solution chemistry. Specifically, they present a simple low-dose method to quantitatively map the liquid layer thickness throughout the entire viewing area of any liquid cell with minimal beam effects even during repeated measurements. Moreover, they show how you can dynamically modulate liquid thickness by tuning the internal pressure in your liquid cell. Ultimately, this paper is a major step forward in the realization of LPEM experiment designs where bulk laboratory-scale solution conditions can be achieved yet at high resolutions. 

Mapping liquid layer thickness

Mapping the liquid layer thickness throughout the entire viewing area is crucial to avoid changes to the chemical environment but still provide the necessary information to 1) estimate which resolution can be reliably achieved, 2) model beam effects and 3) control the liquid thickness throughout the experiment.

Dr. Friedrich and his team use a simple low-dose method to map the liquid layer thickness throughout the entire viewing area. They did so by first acquiring two low-magnification, low-dose TEM images: one flat field image with no electron flux information, and another image with information on the number of electrons locally transmitting the viewing area. This information, combined with the silicon nitride (SiNₓ) membrane thickness, was then used to approximate the liquid layer thickness across the sample. The figure below shows in d) the intensity map of the viewing window area in a water-filled cell, and in e) the liquid layer thickness map calculated from the intensity map using the developed method. Shown in f) is the absolute liquid thickness map obtained from the same liquid cell in (d,e) using well-established STEM-EELS measurements.

Figure 1 - Schematic overview and mapping

Figure 1: a) to c) show the schematic overviews of the liquid cell. d) to f) show the resulting original intensity map, the calculated thickness map using the developed method and the absolute liquid thickness map obtained from the same liquid cell using STEM-EELS measurements, respectively.

The advantages of this method are that it can be adapted to any liquid and microscope which makes it a versatile tool for different experiments. This can be done by approximating the corresponding elastic mean free path (EMFP) from the chemical composition of the liquid and the acceleration voltage of the employed microscope.

Preparing the liquid cell

To prepare the liquid cell, the researchers employed a rather rare machine called the SciTEM (Scienion AG, a CELLINK company, Germany), which automates the liquid handling. The SciTEM is capable of patterning picoliter droplets of solutions onto the chip surface with a predefined array, and automatically loading the top chip to close the liquid cell. Ultimately, this means that accurate liquid volume control and reproducible liquid cell assembly can be achieved. The video below shows this process.

Movie 1: the automated preparation of the liquid cell

Controlling liquid thickness via internal pressure modulation

Because a pressure difference exists between the liquid and the microscope vacuum, the bending of the SiNₓ membrane windows typically occurs. This results in a spatially varying liquid layer thickness that makes it challenging to interpret LPEM results due to a locally varying achievable resolution and diffusion limitations. Therefore, to improve LPEM methodology, one needs to be able to accurately and dynamically control the liquid layer thickness, which has to be achieved by modulating the pressure inside the liquid cell.

Dr. Friedrich and his team show that with reproducible inward bulging of the window membranes, an ultra-thin liquid layer in the central window area for high-resolution imaging can indeed be realized. This is depicted very well in the figure below, showing the evolution of the meniscus in a liquid cell during evaporation. When evaporation occurs (2b), the flat gas-liquid interface gradually becomes curved, and the corresponding radius of curvature becomes smaller. At the same time, outward bulging is being reduced. Finally, as shown in 2d) and 2e), the inward bulging of the membrane is expected.

Figure 2 - Meniscus evolution with evaporation

Figure 2: Evolution of the meniscus in a liquid cell during evaporation

As shown in the in situ LPTEM video below, the liquid cell experienced outward bulging at the very beginning and within 3 minutes, nearly no bulging at all. Shortly after, you can see that an inward-bulged cell was obtained, entirely consistent with the model shown in Figure 2 above. Figure 3 demonstrates this, along with the corresponding intensity profile changes of the diagonal line across the window.

Movie 2: LPEM video showing outward to inward bulging in liquid cell

Figure 3 - Outward to inward bulging

Figure 3: Reversible transformation of a liquid cell containing water from outward to inward bulging via slow evaporation. Below are the intensity and thickness profiles of the bulging transition.

Rapid and dynamic control of liquid thickness

In addition, Dr. Friedrich and his team show that one can dynamically alter liquid thickness in a programmed fashion. They do this by independently controlling the inlet and outlet pressure on the fly via pressure pumps, and therefore the internal pressure inside the cell. Specifically, they show how pressure cycling gives rise to rapid dynamic control over liquid thickness, thus providing an additional adjustable parameter for experiment design. This dynamic control over the liquid layer thickness is depicted in the video below, where liquid thickness was continually mapped during the pressure cycling.

Movie 3: Rapid dynamic control of liquid layer thickness during external pressure cycles. The corresponding intensity and thickness maps are also shown.

Rapid dynamic control over liquid thickness is of key importance, in particular in bypass liquid cell systems, as it can help to overcome confinement problems such as diffusion limitations. In this way, the path can be paved towards achieving bulk solution conditions.

Novelty in findings

This paper contributes on two important fronts. Namely, it provides promising approaches to map and control liquid layer thickness in LPEM experiments with high accuracy and reliability. Using the above approaches, novel LPEM experimental designs with liquid thickness tailored to the requirement of the imaged process become imaginable. We are proud of the role that our LPEM solutions have played in making this research possible and strive to continue enabling groundbreaking research now and in the future.

Dr. Heiner Friedrich
“With this work on measuring and controlling liquid layer thickness using the Ocean system we hope to enable better science in the art of liquid phase electron microscopy.”
Dr. Heiner Friedrich
Assistant Professor |  Eindhoven University of Technology

Original article:

Discover our LPEM solutions:

Discover more publications made possible by our LPEM solutions:

Thomas article feature image

New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

In collaboration with Utrecht University, we develop a novel technique to measure temperature at the nanoscale, showing the remarkable temperature accuracy and homogeneity of our Wildfire Nanochip

Do you want to receive great articles like this in your mailbox? Subscribe to our newsletter.

New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

In collaboration with Utrecht University, we develop a novel technique to measure temperature at the nanoscale, showing the remarkable temperature accuracy and homogeneity of our Wildfire Nanochip

Original article by Thomas P. van Swieten, Tijn van Omme, Dave J. van den Heuvel, Sander J.W. Vonk, Ronald G. Spruit, Florian Meirer, Hugo Pérez Garza , Bert M. Weckhuysen, Andries Meijerink, Freddy T. Rabouw and Robin G. Geitenbeek
Thomas article feature image

The temperature-sensitive luminescence of nanoparticles enables their application as remote thermometers. In fact, the size of these nanothermometers makes them ideal to map temperatures with a high spatial resolution. Yet, conducting high spatial resolution mapping of temperatures that exceed 100°C poses some challenges.

In collaboration with Thomas van Swieten and his fellow colleagues at Utrecht University, we were able to jointly develop a new technique to measure temperature at the nanoscale. In fact, we tested this novel technique on our Wildfire Nanochip and were able to further confirm the Nanochip’s unparalleled temperature accuracy and homogeneity. These experiments also proved how well our models work to predict the temperature distribution across the microheater. Importantly, this particular technique will improve the accuracy of nanothermometry as a whole, not only in micro- and nano-electronics but also in other fields with photonically inhomogeneous substrates.  

The technique: Luminescence nanothermometry

Thermometry on the microscopic scale is an essential characterization tool for the development of nano- and microelectronic devices. However, conventional thermometers like thermocouples are often unable to reliably measure the temperature on this length scale due to their size. This is precisely where remote temperature sensing via optical thermometry techniques comes into play. Thermometry based on luminescence is particularly interesting since it is easily implemented, requiring only the deposition of a luminescent material in or on a sample of interest and the detection of its luminescence. For this reason, luminescence nanothermometry is currently developing into the method of choice for temperature measurements in microscopy.

Homogeneous heat distribution

Our Wildfire Nanochip was specifically designed to enable users a homogeneous heat distribution across the microheater where a sample is positioned. It is particularly due to the unique geometry of the metal spiral, where the windows are placed right at the center, that users are able to enjoy such a remarkable temperature homogeneity. In fact, our Wildfire Nanochip has a temperature uniformity of 98% across the window area and 99.5% across the two central windows. The figure on the right below is a perfect illustration of the chip’s exceptional temperature homogeneity, showing the temperature profile across the membrane and the microheater for a center temperature of 523 K simulated with a finite element model.

The high temperature homogeneity of our Wildfire Nanochips is also owed to the fact that the metal heating spiral is embedded in a silicon nitride membrane. Silicon nitride has many advantages including being chemically inert, mechanically robust and can withstand harsh chemical and temperature environments. 

Tijn article - figure 2 wildfire nanochip homogeneous distribution

On the left: The Wildfire Nanochip, where the metal spiral is represented in orange and the silicon nitride membrane in blue. On the right: Finite element model simulation showing the remarkable temperature homogeneity of the Wildfire Nanochip

Reliable temperature mapping

In this work, the luminescent particles that were used are NaYF₄ nanoparticles doped with Er³⁺ and Yb³⁺. These particles exhibit a strong upconversion when excited with an infrared laser. In other words, they emit photons with a shorter wavelength than the excitation photons. As shown in the figure below, we found that the spectrum of the emitted (green) photons is quite sensitive to temperature.

Tijn article - Figure 1 Intensity vs Wavelength

Green upconversion luminescence of the nanoparticles upon excitation at various temperatures ranging from 303 K (dark red) to 573 K (yellow)

By scanning the laser across a layer of deposited nanoparticles in the confocal microscope, we were able to capture an array of emission spectra. We then converted this emission spectra into a temperature map using the luminescence intensity ratio of the 2 peaks at each pixel. After a number of correction steps, the technique showed a remarkable precision of 1-4 K with a spatial resolution of ∼1 micrometer. It is noteworthy to mention that most other techniques are unable to achieve such a high accuracy like this.

Tijn article - Figure 3 DESKTOP reliable temperature mapping

In a) we scanned the laser across the microheater with the deposited luminescent nanoparticles to generate a map of intensity ratios. b) shows the spectrum at each pixel converted into a temperature to provide a temperature map of the microheater.

Simulation and model accuracy

Using the fully corrected temperature maps, we were able to analyze in depth the temperature homogeneity of the microheater. The figure below shows the horizontal traces through the center of these maps. The simulated temperature profiles (lines) show an excellent match with the experimental traces (dots).This confirms both the reliability of the finite element model as a design tool and the strength of our temperature mapping technique as a characterization tool, achieving a high accuracy and a spatial resolution of ∼1 μm.

Tijn article - temperature mapping in graph

A graph showing the mapping of elevated temperatures. The lines represent the simulated temperature profiles and the experimental traces represent the dots.

We determine the standard deviation of the temperature in the center to quantify the accuracy of this thermometry method and find values of 1 K at 323 K increasing to only 4 K at 513 K. Conclusively, this makes nanothermometry using confocal luminescence spectroscopy a promising method to map temperature profiles not only for microheaters but also in other fields such as biology and catalysis where temperature variations are important but hard to monitor with conventional methods.
Tijn portrait image
“Thanks to the exceptionally good spatial and temperature resolution of this method, we were able to obtain an accurate temperature map of our microheater spiral. This confirmed the excellent temperature homogeneity which was predicted by our finite element models.”
Tijn van Omme
Microsystems Engineer |  DENSsolutions

Original article:

Discover our Wildfire solution:

Discover more publications made possible by Wildfire:

Markus article feature image

The first in situ observation of layered metastable heterostructure formation

Using our Wildfire system, scientists are able to thoroughly investigate the formation of heterostructures from starting materials with vastly different properties

Do you want to receive great articles like this in your mailbox? Subscribe to our newsletter.