Better superconductors with palladium

A Goldilocks material that might be just right: the precious metal palladium could be used to make superconductors that remain superconducting even at relatively high temperatures, show calculations by TU Wien.

Peer-Reviewed Publication

VIENNA UNIVERSITY OF TECHNOLOGY

It is one of the most exciting races in modern physics: How can we produce the best superconductors that remain superconducting even at the highest possible temperatures and ambient pressure? In recent years, a new era of superconductivity has begun with the discovery of nickelates. These superconductors are based on nickel, which is why many scientists speak of the “nickel age of superconductivity research”. In many respects, nickelates are similar to cuprates, which are based on copper and were discovered in the 1980s.

But now a new class of materials is coming into play: In a cooperation between TU Wien and universities in Japan, it was possible to simulate the behaviour of various materials more precisely on the computer than before. There is a "Goldilocks zone" in which superconductivity works particularly well. And this zone is reached neither with nickel nor with copper, but with palladium. This could usher in a new “age of palladates" in superconductivity research. The results have now been published in the scientific journal Physical Review Letters.

The search for higher transition temperatures

At high temperatures, superconductors behave very similar to other conducting materials. But when they are cooled below a certain "critical temperature", they change dramatically: their electrical resistance disappears completely and suddenly they can conduct electricity without any loss. This limit, at which a material changes between a superconducting and a normally conducting state, is called the "critical temperature".

"We have now been able to calculate this  "critical temperature" for a whole range of materials. With our  modelling on high-performance computers, we were able to predict the phase diagram of nickelate superconductivity with a high degree of accuracy, as the experiments then showed later," says Prof. Karsten Held from the Institute of Solid State Physics at TU Wien.

Many materials become superconducting only just above absolute zero (-273.15°C), while others retain their superconducting properties even at much higher temperatures. A superconductor that still remains superconducting at normal room temperature and normal atmospheric pressure would fundamentally revolutionise the way we generate, transport and use electricity. However, such a material has not yet been discovered. Nevertheless, high-temperature superconductors, including those from the cuprate class, play an important role in technology - for example, in the transmission of large currents or in the production of extremely strong magnetic fields.

Copper? Nickel? Or Palladium?

The search for the best possible superconducting materials is difficult: there are many different chemical elements that come into question. You can put them together in different structures, you can add tiny traces of other elements to optimise superconductivity. "To find suitable candidates, you have to understand on a quantum-physical level how the electrons interact with each other in the material," says Prof. Karsten Held.

This showed that there is an optimum for the interaction strength of the electrons. The interaction must be strong, but also not too strong. There is a “golden zone” in between that makes it possible to achieve the highest transition temperatures.

Palladates as the optimal solution

This golden zone of medium interaction can be reached neither with cuprates nor with nickelates - but one can hit the bull's eye with a new type of material: so-called palladates. "Palladium is directly one line below nickel in the periodic table. The properties are similar, but the electrons there are on average somewhat further away from the atomic nucleus and each other, so the electronic interaction is weaker," says Karsten Held.

The model calculations show how to achieve optimal transition temperatures for palladium data. "The computational results are very promising," says Karsten Held. "We hope that we can now use them to initiate experimental research. If we have a whole new, additional class of materials available with palladates to better understand superconductivity and to create even better superconductors, this could bring the entire research field forward."

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JOURNAL

Physical Review Letters

DOI

10.1103/PhysRevLett.130.166002 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Optimizing Superconductivity: From Cuprates via Nickelates to Palladates

Algae in Swedish lakes provide insights to how complex life on Earth developed

Peer-Reviewed Publication

LUND UNIVERSITY

By studying green algae in Swedish lakes, a research team, led by Lund University in Sweden, has succeeded in identifying which environmental conditions promote multicellularity. The results give us new clues to the amazing paths of evolution.

The evolution of multicellular life has played a pivotal role in shaping biological diversity. However, we have up until now known surprisingly little about the natural environmental conditions that favour the formation of multicellular groups.

The cooperation between cells within multicellular organisms has enabled eyes, wings and leaves to evolve. The predominant explanation for why multicellularity evolves is that being in a group enables species to better cope with environmental challenges – where being in a large group can, for instance, protect cells against being eaten.

"Our results challenge this idea, showing that multicellular groups form, not because they are inherently beneficial, but rather as a by-product of single-celled strategies to reduce environmental stress. In particular, cells produce a range of substances to protect themselves from the environment and these substances appear to prevent daughter cells from dispersing away from their mother cell", says Charlie Cornwallis, biology researcher at Lund University.

To understand how and why single-celled organisms evolve to be multicellular, the scientists experimented on green algae where some species are always single-celled, some are single-celled but become multicellular under certain conditions, while others are always multicellular containing thousands of cells. They could then identify the environmental conditions that promote multicellularity and find out the benefits and costs for organisms. The researchers then combined data with information on the environments that single-celled and multicellular green algae are adapted to across the whole of Sweden.

"I was surprised that there were no benefits or costs to living in multicellular groups. The conditions that individual cells experience can be extremely different when swimming around on their own, to being stuck to other cells and having to coordinate activities. Imagine you were physically tied to your family members, I think it would have quite an effect on you", says Charlie Cornwallis.

The study was conducted in Swedish lakes, and it not only provides information on which green algae occur where, and why – it also helps us understand the origins of biological diversity that shape the world around us.

"The results of this study contribute to our understanding of how complex life on Earth has evolved. They also provide information on how a key group of species – green algae that generate fuel for ecosystems – are able to reproduce and survive under different environmental conditions. The next time you walk along the shores of a lake rich in nitrogen just imagine that this fosters the evolution of multicellular life", says Charlie Cornwallis.

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JOURNAL

Nature Ecology & Evolution

DOI

10.1038/s41559-023-02044-6 

ARTICLE TITLE

Single-cell adaptations shape evolutionary transitions to multicellularity in green algae

120-year-old storm’s secrets key to understanding weather risks

Peer-Reviewed Publication

UNIVERSITY OF READING

A severe windstorm that battered the UK more than a century ago produced some of the strongest winds[OS1]  that Britain has ever seen, a team of scientists have found after recovering old weather records. 

Old weather measurements, first recorded on paper after Storm Ulysses hit the UK in February 1903, have shed new light on what was one of the most severe storms to have hit the British Isles.

By turning hand-written weather data into digital records, the research team has laid the way to better understand other historical storms, floods and heatwaves. These observations from the past can help experts to understand the risks of extreme weather now and in the future. 

Professor Ed Hawkins, a climate scientist at the University of Reading and the National Centre for Atmospheric Science, led the research. He said: “We knew the storm we analysed was a big one, but we didn’t know our rescued data would show that it is among the top four storms for strongest winds across England and Wales. 

“This study is a great example of how rescuing old paper records can help us to better understand storms from decades gone by. Unlocking these secrets from the past could transform our understanding of extreme weather and the risks they pose to us today.”

Into the archives

Published today (Monday, 24 April) in Natural Hazards and Earth System Sciences, the research indicates that many storms that occurred before 1950 are left unstudied as billions of pieces of data exist only on paper, stored in archives around the world.

But a team of scientists led by Professor Hawkins delved into the archives to convert hand-written observations relating to Storm Ulysses from paper to digital. The cyclone caused multiple deaths and heavily damaged infrastructure and ships when it passed across Ireland and the UK between 26 and 27 February 1903. 

Using the new digital data, the research team was able to use techniques similar to modern weather forecasting to simulate the storm and accurately assess the strength of Storm Ulysses' winds. Comparisons with independent weather observations, such as rainfall data, as well as photographs and written accounts from 1903 that outlined the devastation caused by the cyclone, helped to provide credibility for the reconstruction.

The reanalysis is beneficial for understanding the risks of extreme weather events as it showed that the winds experienced in some locations during Storm Ulysses would be rarer than once in 100 years. Having information about such a rare event provides valuable insight into the potential damage a similar storm could cause now in the future.

The 1903 storm is named Storm Ulysses because the damage to thousands of trees in Dublin is mentioned in the novel Ulysses by James Joyce, the events of which are set the year after the storm.

Rescuing the weather

The rescuing of atmospheric observations related to Storm Ulysses is not the first time Professor Ed Hawkins has led weather record recovery. National rainfall data from as far back as 1836 became available in 2022 after the University’s Department of Meteorology and 16,000 volunteers helped to restore 5.2 million observations. 

The Rainfall Rescue project provided more context around recent changes in rainfall due to human-caused climate change.

 

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JOURNAL

Natural Hazards and Earth System Sciences

DOI

10.5194/nhess-23-1465-2023 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Rescuing historical weather observations improves quantification of severe windstorm risks

ARTICLE PUBLICATION DATE

24-Apr-2023

Massive iceberg discharges during the last ice age had no impact on nearby Greenland, raising new questions about climate dynamics

Peer-Reviewed Publication

OREGON STATE UNIVERSITY

 

IMAGE: THE GRAPHIC DEPICTS THE IMPACTS OF HEINRICH EVENTS GLOBALLY. view more 

CREDIT: OLIVER DAY, OREGON STATE UNIVERSITY

CORVALLIS, Ore. – During the last ice age, massive icebergs periodically broke off from an ice sheet covering a large swath of North America and discharged rapidly melting ice into the North Atlantic Ocean around Greenland, triggering abrupt climate change impacts across the globe.

These sudden episodes, called Heinrich Events, occurred between 16,000 and 60,000 years ago. They altered the circulation of the world’s oceans, spurring cooling in the North Atlantic and impacting monsoon rainfall around the world.

But little was known about the events’ effect on nearby Greenland, which is thought to be very sensitive to events in the North Atlantic. A new study from Oregon State University researchers, just published in the journal Nature, provides a definitive answer.

“It turns out, nothing happened in Greenland. The temperature just stayed the same,” said the study’s lead author, Kaden Martin, a fourth-year doctoral candidate in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “They had front-row seats to this action but didn’t see the show.”

Instead, the researchers found that these Heinrich events caused rapid warming in Antarctica, at the other end of the globe.

The researchers anticipated Greenland, in close proximity to the ice sheet, would have experienced some kind of cooling. To find that these Heinrich Events had no discernible impact on temperatures in Greenland is surprising and could have repercussions for scientists’ understanding of past climate dynamics, said study co-author Christo Buizert, an assistant professor in the College of Earth, Ocean, and Atmospheric Sciences.

“If anything, our findings raise more questions than answers,” said Buizert, a climate change specialist who uses ice cores from Greenland and Antarctica to reconstruct and understand the Earth’s climate history. “This really changes how we look at these massive events in the North Atlantic. It’s puzzling that far-flung Antarctica responds more strongly than nearby Greenland.”

Scientists drill and preserve ice cores to study past climate history through analysis of the dust and tiny air bubbles that have been trapped in the ice over time. Ice cores from Greenland and Antarctica provide important records of Earth’s atmospheric changes over hundreds of thousands of years.

Records from ice cores from those regions have served as pillars for scientists’ understanding of past climate events, with ice collected from both locations often telling similar stories, Martin said.

The impact of Heinrich Events on Greenland and Antarctica was not well understood, spurring Martin and Buizert to try to find out more about what was happening in those parts of the world.

The core used for the latest study was collected in 1992 from the highest point of Greenland, where the ice sheet is around 2 miles thick. Since then, the core has been in storage in the National Science Foundation Ice Core Facility in Denver.

Advancement in scientific tools and measurements over the last few decades gave Martin, Buizert and their colleagues the opportunity to re-examine the core using new methods.

The analysis shows that no changes in temperatures occurred in Greenland during Heinrich Events. But it also provides a very clear connection between Heinrich Events and the Antarctic response.

“When these big iceberg discharges happen in the Arctic, we now know that Antarctica responds right away,” Buizert said. “What happens in one part of the world has an effect on the rest of the world. This inter-hemispheric connection is likely caused by change in global wind patterns.”

The finding challenges the current understanding of global climate dynamics during these massive events and raises new questions for researchers, Buizert said. The researchers’ next step is to take the new information and run it through climate models to see if the models can replicate what occurred.

“There has to be a story that fits all of the evidence, something that connects all the dots,” he said. “Our discovery adds two new dots; it’s not the full story, and it may not be the main story. It is possible that the Pacific Ocean plays an important role that we haven’t figured out yet.”

The ultimate goal is to better understand how the climate system is connected and how the components all interact, the researchers said.

“While Heinrich Events are not going to happen in the future, abrupt changes in the globally interconnected climate system will happen again,” Martin said. “Understanding the global dynamics of the climate system can help us better project future impacts and inform how we respond and adapt.”

Additional co-authors are Ed Brook, Jon Edwards, Michael Kalk and Ben Riddell-Young of OSU; Ross Beaudette and Jeffrey Severinghaus of the Scripps Institution of Oceanography; and Todd Sowers of Pennsylvania State University.

The research was supported by the National Science Foundation, the Global Climate Change Foundation and the Gary Comer Science and Education Foundation.

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JOURNAL

Nature

DOI

10.1038/s41586-023-05875-2 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

'Bipolar impact and phasing of Heinrich-type climate variability

ARTICLE PUBLICATION DATE

24-Apr-2023

One old tree is worth 400 saplings – Dresden forestry expert Andreas Roloff calls for more respect for trees

Business Announcement

TECHNISCHE UNIVERSITÄT DRESDEN

 

IMAGE: THE COLLM LINDEN, SPRING 2023 view more 

CREDIT: MATTHIAS GOEDE

It’s an extraordinarily huge sum. For this reason, Prof. Andreas Roloff, forestry scientist with a wealth of expertise in old trees, did the math several times over, always using different methods. But the results remained the same. In order to match the environmental benefits that an old tree with a crown circumference of 20 meters provides – such as air filtration, shade, cooling and carbon storage – you need about 400 saplings.

“The magnitude of this ratio also came as a surprise to me,” says Andreas Roloff. “But it emphasizes how much more we need to respect and care for the old trees in our environment and how the decision to cut them down, for instance to make way for construction projects, should not be made lightly.” Felled trees are required by law to be replaced by one to three saplings. At best, this serves as a pretext only.  

Andreas Roloff, former Director of the Institute of Forest Botany and Forest Zoology as well as the Forest Park Tharandt, is now a Senior Professor at TU Dresden. For many years, he has been researching topics such as tree aging, tree species and tree care, as well as their reactions and adaptations to drought stress, especially in residential areas. Along with being the topic of his research, the protection and conservation of old trees is a topic close to his heart. Roloff has penned many texts including a publication on heritage trees and how to conserve them.

For his lecture during this year’s Dresdner StadtBaumtage (Dresden City Tree Days), organized since 2007 by the Chair of Forest Botany and the Office of Urban Green Spaces and Waste Management in Dresden and Tharandt, Andreas Roloff investigated the conditions and factors trees need to live for 1,000 years, to become “Methuselah trees.” He stumbled across this astonishing statistic almost by accident.

“Now, we can define eleven biological properties specific to trees which impact their life expectancy. The more of these a tree species can combine, the older it can theoretically become – if conditions, location and tree care are right and, above all, the tree is not cut down before its time,” explains Roloff. 

If you’re thinking more in human lifetimes than Methuselah years and would like to plant a tree in your garden, Dresden’s forestry scientists have developed criteria for choosing the best site using a wide range of categories. Two databases are available for this purpose: In KLimaArtenMatrix, 250 tree and shrub species are listed according to their drought stress resistance. And Citree uses a ranking based on 65 categories or properties to select the best trees from about 400 species and varieties for a specific site.   

Even the best of databases can’t help if trees are not properly cared for, especially in residential areas and parks. For this reason, forestry graduates and professionals in Dresden can also learn tree inspection and care from scratch in certification courses from the Deutsches Baum-Institut (German Tree Institute). “We now have very exact provisions to ensure high quality. It is not uncommon for the seemingly cheapest methods, such as tree topping, to turn out to be the most expensive in the long run due to the tree damage and follow-up costs they result in,” explains Andreas Roloff. With regard to the costs of planting new trees and the immense environmental benefits of old trees, it would be fair to ask what will end up costing you more paper.

At the end of March, Andreas Roloff was able to witness an extremely unusual tree rescue thanks to professional care. The Collm Linden, estimated to be 800 years old, is the oldest tree in Saxony and has been listed as a national heritage tree since October 2022. Earlier this year, it was in danger of collapsing when its leaves started sprouting. Armed with hand saws, eight arborists carefully pruned the ancient tree branch by branch in order to save it. “This is of course an exceptional situation and often unaffordable for regional municipalities,” said Andreas Roloff. “But for me, it was an incredibly awe-inspiring and moving experience. Thanks to this work, the Collm Linden is now secured and equipped for the next decades of its life.

 

Background:
This year’s Dresdner StadtBaumtage (Dresden City Tree Days) took place on March 9 and 10 and focused on pertinent questions of tree care and use, the protection of historical monuments, nature conservation, tree-lined avenues and old tree species. Major discussion topics included the more effective use of rainwater for garden maintenance in cities, using Dresden as an example, as well as the in part immense consequences and challenges that have arisen in Saxony’s gardens and parks due to climate change. The German-language conference transcript is available at www.deutsches-bauminstitut.de.

Nationalerbe-Bäume – Konzeption und Ziele, Umsetzung und Realisierung zum Schutz alter Bäume in Deutschland: die ersten 16 Kandidaten in allen Bundesländern. (National Heritage Trees – Conception and Objectives, Execution and Implementation for the Protection of Old Trees in Germany: The First 16 Candidates in All German States.) Verlag Forstbotanik TU Dresden, Tharandt 2022 (ISBN 978-3-86780-704-3). Available to download at https://nationalerbe-baeume.de/2022/05/01/buch-neuerscheinung-zur-initiative/

Andreas Roloff (2023): Methusalembäume - Wie und warum können manche Baumarten 1000 Jahre alt werden? Ursachen, Prozesse, Wirkungen, Nebenwirkungen und Konsequenzen. (Methuselah Trees - How and Why Can Some Tree Species Reach 1,000 Years of Age? Causes, Processes, Impact, Secondary Effects and Consequences.) Forstwiss. Beitr. Tharandt Beih. 24: 159-179

Andreas Roloff (2023): Inspiration Natur im Jahreslauf. Mentale Stärkung und Motivation durch bewusstes Erleben. (Inspiring Nature Throughout the Year. Drawing Mental Strength and Motivation from Conscious Experience.) Verlag Quelle & Meyer

Andreas Roloff (2017): Der Charakter unserer Bäume. Ihre Eigenschaften und Besonderheiten Beschreibung. (The Character of Our Trees. Their Properties and Distinctive Features.) Verlag Ulmer Eugen Verlag

Study: Mountain quail may benefit from high severity wildfire

Findings from acoustic monitoring in the Sierra Nevada

Peer-Reviewed Publication

CORNELL UNIVERSITY

 

IMAGE: MOUNTAIN QUAIL. view more 

CREDIT: KRISTIN M. BRUNK, CORNELL LAB OF ORNITHOLOGY.

Ithaca, NY--Mountain Quail are an under-studied but recreationally-valued management indicator species in California's Sierra Nevada. They are notoriously difficult to study due to their penchant for impenetrable, dense, shrubby habitats, high elevations, and steep slopes. In this study, researchers used 1,636 autonomous recording units across about 22,000 square kilometers to conduct the first ever systematic and comprehensive study of Mountain Quail habitat associations and fire ecology in the Sierra Nevada.

Researchers from the Cornell Lab of Ornithology, the University of Minnesota, Univesity of Wisconsin-Madison, and the University of Montana conducted this research.

The scientists found that Mountain Quail were more common than previously thought (mean occupancy was about 50% across study sites). They also found positive associations between Mountain Quail occupancy and high severity fire. Mountain Quail were most positively associated with areas that had burned at high severity in the past 6-10 years, but found positive associations ranging between 1 and 35 years after high-severity fire.

Future fire regimes in the Sierra Nevada are expected to include more frequent and larger high-severity fires, which are predicted to negatively impact many iconic Sierra Nevada species. Our results suggest that Mountain Quail may be "winners" in the face of altered fire regimes in the Sierra Nevada. This work is a reminder that there will be both winners and losers as the dynamics of wildfire are altered in the era of climate change. 

Reference:
Brunk, K.M., Gutiérrez, R.J., Peery, M.Z. et al. Quail on fire: changing fire regimes may benefit mountain quail in fire-adapted forests. fire ecol 19, 19 (2023). https://doi.org/10.1186/s42408-023-00180-9

  

Acoustic monitoring unit in a burned forest in the Sierra Nevada.

Acoustic monitoring unit in a Sierra Nevada forest.

CREDIT

Kristin M. Brunk, Cornell Lab of Ornithology.

JOURNAL

Fire Ecology

DOI

10.1186/s42408-023-00180-9 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Quail on fire: changing fire regimes may benefit mountain quail in fire-adapted forests

Fear not the deadlines, new research finds

First-of-its-kind study suggest researchers’ stress levels stay the same with or without deadlines

Peer-Reviewed Publication

UNIVERSITY OF HOUSTON

 

IMAGE: IOANNIS PAVLIDIS, PROFESSOR OF COMPUTER SCIENCE AND DIRECTOR OF THE AFFECTIVE AND DATA COMPUTING LABORATORY AT THE UNIVERSITY OF HOUSTON view more 

CREDIT: UNIVERSITY OF HOUSTON

Deadlines are part and parcel of modern knowledge work. Journalists must serve their weekly columns, managers must turn in their monthly reports, and researchers must submit their papers and proposals on time. Despite their ubiquity, deadlines conjure up negative feelings and are perceived as challenging events. Accordingly, there has been a trend to do away with deadlines, where possible. For instance, the National Science Foundation (NSF) in the United States introduced no-deadline submissions in some of its funding programs. Critics, however, have been arguing that although deadlines may be painful, they are necessary, because they motivate people to act.

Researchers from the University of Houston, Texas A&M, and the Polytechnic of Milano set out to address the question at the heart of the matter: “Does knowledge work near deadlines incur higher sympathetic load than knowledge work away from deadlines?” Sympathetic activation is the state of physiological arousal that indicates how much people are “on the tips of their toes,” and often leads to stress. This is why its intensity and duration should be kept in check, according to the researchers.

The first-of-its-kind study published in the Proceedings of the ACM Human Factors in Computing, was led by Ioannis Pavlidis, professor of computer science and director of the Affective and Data Computing Laboratory at UH.

Per an institutionally approved ethical protocol, 10 consenting researchers were monitored as they worked at the office in the two days leading to a critical deadline, and two other days without an impeding deadline. Miniature cameras were placed at the researchers’ university office to unobtrusively record their facial physiology and expressions, as well as their movements throughout the working day. The participants’ sympathetic activation was measured every second through quantification of their imaged perinasal perspiration levels.

Applying advanced data modeling on hundreds of hours of data recordings, the team found that researchers experience high sympathetic activation while working, which speaks to the challenging nature of the research profession. Surprisingly, this high sympathetic activation remains about the same with or without deadlines.

“Research is tough every day,” said Pavlidis. “Using a metaphor, if you are under heavy rain all the time, if one day the rain is a little heavier, it would not make much difference to you because you are already wet to the bone. This is what our models show with respect to the effect of deadlines on researchers.”

The only factors found to exacerbate sympathetic activation were extensive smartphone use and prolific reading/writing. The first factor is a manifestation of the gadget-based addiction trends that have altered human behaviors across the board. The second factor is integral to research work, and thus unavoidable. Thankfully, however, researchers appear to auto-regulate increases in their sympathetic activation by instinctively adjusting the frequency of physical breaks. It was observed that on average, researchers take one physical break every two hours. From this baseline, data analysis showed that for every 50% increase in sympathetic activation, the break frequency nearly doubles, revealing the limits of cognitive work under increasing stress.

“Our naturalistic study not only brings fresh insights into researchers’ behaviors but also challenges some prevailing views about deadlines”, Pavlidis said. “With the recent advances in affective computing, I expect such naturalistic studies to proliferate across domains, challenging misconceptions we hold about a lot of things,” added Pavlidis.

The study was funded by a grant from the National Science Foundation.

Four face illustrations conveying the plight of knowledge workers during research pursuits near and afar from deadlines. The facial expressions and postures were taken from actual observational data during the naturalistic study. The individual characteristics of the researchers were altered to preserve anonymity.

CREDIT

University of Houston

DOI

10.1145/3544549.3585585 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Sympathetic Activation in Deadlines of Deskbound Research - A Study in the Wild

ARTICLE PUBLICATION DATE

19-Apr-2023

FREELANCER

Researchers team up with national lab for innovative look at copper reactions

A better understanding of oxide catalysts could inspire solutions for clean energy

Peer-Reviewed Publication

BINGHAMTON UNIVERSITY

 

IMAGE: GUANGWEN ZHOU IS A PROFESSOR OF MECHANICAL ENGINEERING AT THE WATSON COLLEGE OF ENGINEERING AND APPLIED SCIENCE AT BINGHAMTON UNIVERSITY, STATE UNIVERSITY OF NEW YORK. view more 

CREDIT: BINGHAMTON UNIVERSITY, STATE UNIVERSITY OF NEW YORK

BINGHAMTON, N.Y. -- Researchers at Binghamton University partnered with the Center for Functional Nanomaterials (CFN) — a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory — to get a better look at how peroxides on the surface of copper oxide promote the oxidation of hydrogen but inhibit the oxidation of carbon monoxide, allowing them to steer oxidation reactions.

They were able to observe these quick changes with two complimentary spectroscopy methods that have not been used in this way. The results of this work have been published in the journal Proceedings of the National Academy of Sciences.

“A nice feature of CFN lies not only in its state-of-the-art facilities for science, but also the opportunities it provides to train young researchers,” said Guangwen Zhou, a professor at the Thomas J. Watson College of Engineering and Applied Science’s Department of Mechanical Engineering and the Materials Science and Engineering program at Binghamton. ”Each of the students involved has benefited from extensive, hands-on experience in the microscopy and spectroscopy tools available at CFN.”

This work was accomplished with the contributions of four PhD students in Zhou’s group: Yaguang Zhu and Jianyu Wang, the first co-authors of this paper, and Shyam Patel and Chaoran Li. All these students are early in their career, having just earned their PhDs in 2022.

“Copper is one of the most studied and relevant surfaces, both in catalysis and in corrosion science,” said Anibal Boscoboinik, materials scientist at CFN. “So many mechanical parts that are used in industry are made of copper, so trying to understand this element of the corrosion processes is very important.”

“I’ve always liked looking at copper systems,” said Ashley Head, also a materials scientist at CFN. “They have such interesting properties and reactions, some of which are really striking.”

Gaining a better understanding of oxide catalysts gives researchers more control of the chemical reactions they produce, including solutions for clean energy. Copper, for example, can catalytically form and convert methanol into valuable fuels, so being able to control the amount of oxygen and number of electrons on copper is a key step to efficient chemical reactions.

Peroxide as a proxy

Peroxides are chemical compounds that contain two oxygen atoms linked by shared electrons. The bond in peroxides is fairly weak, allowing other chemicals to alter its structure, which makes them very reactive. In this experiment, scientists were able to alter the redox steps of catalytic oxidation reactions on an oxidized copper surface (CuO) by identifying the makeup of peroxide species formed with different gases: O2 (oxygen), H2 (hydrogen) and CO (carbon monoxide).

Redox is a combination of reduction and oxidation. In this process, the oxidizing agent gains an electron and the reducing agent loses an electron. When comparing these different peroxide species and how these steps played out, researchers found that a surface layer of peroxide significantly enhanced CuO reducibility in favor of H2 oxidation. They also found that, on the other hand, it acted as an inhibitor to suppress CuO reduction against CO (carbon monoxide) oxidation. They found that this opposite effect of the peroxide on the two oxidation reactions stems from the modification of the surface sites where the reaction takes place.

By finding these bonding sites and learning how they promote or inhibit oxidation, scientists can use these gases to gain more control of how these reactions play out. To tune these reactions, though, scientists had to get a clear look at what was happening.

The right tools for the job

Studying this reaction in situ was important to the team, since peroxides are very reactive and these changes happen fast. Without the right tools or environment, it’s hard to catch such a limited moment on the surface.

Peroxide species on copper surfaces were never observed using in-situ infrared (IR) spectroscopy in the past. With this technique, researchers use infrared radiation to get a better understanding of a material’s chemical properties by looking at the way the radiation is absorbed or reflected under reaction conditions. In this experiment, scientists were able to differentiate “species” of peroxide, with very slight variations in the oxygen they were carrying, which would have otherwise been very hard to identify on a metal oxide surface.

“I got really excited when I was looking up the infrared spectra of these peroxide species on a surface and seeing that there weren’t many publications. It was exciting that we could see these differences using a technique that’s not widely applied to these kind of species,” Head said.

IR spectroscopy on its own wasn’t enough to be sure though, which is why the team also used another spectroscopy technique called ambient pressure X-ray Photoelectron Spectroscopy (XPS). XPS uses lower energy X-rays to kick electrons out of the sample. The energy of these electrons gives scientists clues about the chemical properties of atoms in the sample. Having both techniques available through the CFN User Program was key to making this research possible.

“One of the things that we pride ourselves in is the instruments that we have and modified here,” Boscoboinik said. “Our instruments are connected, so users can move the sample in a controlled environment between these two techniques and study them in situ to get complementary information. In most other circumstances, a user would have to take the sample out to go to a different instrument, and that change of environment could alter its surface.”

Future findings

The results of this study may apply to other types of reactions and other catalysts besides copper. These findings and the processes and techniques that led scientists there could find their ways into related research. Metal oxides are widely used as catalysts themselves or components in catalysts. Tuning peroxide formation on other oxides could be a way to block or enhance surface reactions during other catalytic processes.

“I’m involved in some other projects related to copper and copper oxides, including transforming carbon dioxide to methanol to use as a fuel for clean energy,” Head said. “Looking at these peroxides on the same surface that I use has the potential to make an impact on other projects using copper and other metal oxides.”

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2215189120 

ARTICLE TITLE

Tuning the surface reactivity of oxides by peroxide species