From ETH Zürich: “Measuring ethanol’s deadly twin”

From ETH Zürich

16.09.2019
Fabio Bergamin

ETH researchers have developed an inexpensive, handheld measuring device that can distinguish between methanol and potable alcohol. It offers a simple, quick method of detecting adulterated or contaminated alcoholic beverages and is able to diagnose methanol poisoning in exhaled breath.

Women in India sell home-brewed alcohol, which may contain toxic amounts of methanol. (Photograph: Shutterstock / Steve Estvanik)

Methanol is sometimes referred to as ethanol’s deadly twin. While the latter is the intoxicating ingredient in wine, beer and schnapps, the former is a chemical that becomes highly toxic when metabolised by the human body. Even a relatively small amount of methanol can cause blindness or even prove fatal if left untreated.

Cases of poisoning from the consumption of alcoholic beverages tainted with methanol occur time and again, particularly in developing and emerging countries, because alcoholic fermentation also produces small quantities of methanol. Whenever alcohol is unprofessionally distilled in backyard operations, relevant amounts of methanol may end up in the liquor. Beverages that have been adulterated with windscreen washer fluid or other liquids containing methanol are another potential cause of poisoning.

Beverage analyses and the breath test

Until now, methanol could be distinguished from ethanol only in a chemical analysis laboratory. Even hospitals require relatively large, expensive equipment in order to diagnose methanol poisoning. “These appliances are rarely available in emerging and developing countries, where outbreaks of methanol poisoning are most prevalent,” says Andreas Güntner, a research group leader at the Particle Technology Laboratory of ETH Professor Sotiris Pratsinis and a researcher at the University Hospital Zürich.

He and his colleagues have now developed an affordable handheld device based on a small metal oxide sensor. It is able to detect adulterated alcohol within two minutes by “sniffing out” methanol and ethanol vapours from a beverage. Moreover, the tool can also be used to diagnose methanol poisoning by analysing a patient’s exhaled breath. In an emergency, this helps ensure the appropriate measures are taken without delay.

Separating methanol from ethanol

There’s nothing new about using metal oxide sensors to measure alcoholic vapours. However, this method was unable to distinguish between different alcohols, such as ethanol and methanol. “Even the breathalyser tests used by the police measure only ethanol, although some devices also erroneously identify methanol as ethanol,” explains Jan van den Broek, a doctoral student at ETH and the lead author of the study.

First, the ETH scientists developed a highly sensitive alcohol sensor using nanoparticles of tin oxide doped with palladium. Next, they used a trick to differentiate between methanol and ethanol. Instead of analysing the sample directly with the sensor, the two types of alcohol are first separated in an attached tube filled with a porous polymer, through which the sample air is sucked by a small pump. As its molecules are smaller, methanol passes through the polymer tube more quickly than ethanol.

The millimetre-sized black dot in the centre of the gold section is the alcohol sensor.

In this image, the sensor is inside the white casing. To its right is the polymer tube in which methanol is separated from ethanol. (Photographs: Van den Broek J et al. Nature Communications 2019)

The measuring device proved to be exceptionally sensitive. In laboratory tests, it detected even trace amounts of methanol contamination selectively in alcoholic beverages, down to the low legal limits. Furthermore, the scientists analysed breath samples from a person who had previously drunk rum. For test purposes, the researchers subsequently added a small quantity of methanol to the breath sample.

Patent pending

The researchers have filed a patent application for the measuring method. They are now working to integrate the technology into a device that can be put to practical use. “This technology is low cost, making it suitable for use in developing countries as well. Moreover, it’s simple to use and can be operated even without laboratory training, for example by authorities or tourists,” Güntner says. It is also ideal for quality control in distilleries.

Methanol is more than just a nuisance in conjunction with alcoholic beverages, it is also an important industrial chemical – and one that might come to play an even more important role: methanol is being considered as a potential future fuel, since vehicles can be powered with methanol fuel cells. So a further application for the new technology could be as an alarm sensor to detect leaks in tanks.

The study was part of the University Medicine Zürich – Zürich Exhalomics flagship project.

Science paper:
Highly selective detection of methanol over ethanol by a handheld gas sensor
Nature Communications

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ETH Zürich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

Founded in 1855, ETH Zürich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zürich, underlining the excellent reputation of the university.

From University of North Carolina via EarthSky: “Why carbon dioxide has such outsized influence on Earth’s climate”

From University of North Carolina

via

EarthSky

September 16, 2019
Jason West

Carbon dioxide, CO2, makes up less than one-twentieth of 1% of Earth’s atmosphere. How does this relatively scarce gas control Earth’s thermostat?

I am often asked how carbon dioxide can have an important effect on global climate when its concentration is so small – just 0.041% of Earth’s atmosphere. And human activities are responsible for just 32% of that amount.

The ‘Keeling Curve,’ named for scientist Charles David Keeling, tracks the accumulation of carbon dioxide in Earth’s atmosphere, measured in parts per million. Image via Scripps Institution of Oceanography.

NASA Orbiting Carbon Observatory 2, NASA JPL-Caltech

Early greenhouse science

The scientists who first identified carbon dioxide’s importance for climate in the 1850s were also surprised by its influence. Working separately, John Tyndall in England and Eunice Foote in the United States found that carbon dioxide, water vapor and methane all absorbed heat, while more abundant gases did not.

Scientists had already calculated that the Earth was about 59 degrees Fahrenheit (33 degrees Celsius) warmer than it should be, given the amount of sunlight reaching its surface. The best explanation for that discrepancy was that the atmosphere retained heat to warm the planet.

Tyndall and Foote showed that nitrogen and oxygen, which together account for 99% of the atmosphere, had essentially no influence on Earth’s temperature because they did not absorb heat. Rather, they found that gases present in much smaller concentrations were entirely responsible for maintaining temperatures that made the Earth habitable, by trapping heat to create a natural greenhouse effect.

A blanket in the atmosphere

Earth constantly receives energy from the sun and radiates it back into space. For the planet’s temperature to remain constant, the net heat it receives from the sun must be balanced by outgoing heat that it gives off.

Since the sun is hot, it gives off energy in the form of shortwave radiation at mainly ultraviolet and visible wavelengths. Earth is much cooler, so it emits heat as infrared radiation, which has longer wavelengths.

The electromagnetic spectrum is the range of all types of EM radiation – energy that travels and spreads out as it goes. The sun is much hotter than the Earth, so it emits radiation at a higher energy level, which has a shorter wavelength. Image via NASA.

Carbon dioxide and other heat-trapping gases have molecular structures that enable them to absorb infrared radiation. The bonds between atoms in a molecule can vibrate in particular ways, like the pitch of a piano string. When the energy of a photon corresponds to the frequency of the molecule, it is absorbed and its energy transfers to the molecule.

Carbon dioxide and other heat-trapping gases have three or more atoms and frequencies that correspond to infrared radiation emitted by Earth. Oxygen and nitrogen, with just two atoms in their molecules, do not absorb infrared radiation.

Most incoming shortwave radiation from the sun passes through the atmosphere without being absorbed. But most outgoing infrared radiation is absorbed by heat-trapping gases in the atmosphere. Then they can release, or re-radiate, that heat. Some returns to Earth’s surface, keeping it warmer than it would be otherwise.

Earth receives solar energy from the sun (yellow), and returns energy back to space by reflecting some incoming light and radiating heat (red). Greenhouse gases trap some of that heat and return it to the planet’s surface. Image via NASA/Wikimedia.

Research on heat transmission

During the Cold War, the absorption of infrared radiation by many different gases was studied extensively. The work was led by the U.S. Air Force, which was developing heat-seeking missiles and needed to understand how to detect heat passing through air.

This research enabled scientists to understand the climate and atmospheric composition of all planets in the solar system by observing their infrared signatures. For example, Venus is about 870 F (470 C) because its thick atmosphere is 96.5% carbon dioxide.

It also informed weather forecast and climate models, allowing them to quantify how much infrared radiation is retained in the atmosphere and returned to Earth’s surface.

People sometimes ask me why carbon dioxide is important for climate, given that water vapor absorbs more infrared radiation and the two gases absorb at several of the same wavelengths. The reason is that Earth’s upper atmosphere controls the radiation that escapes to space. The upper atmosphere is much less dense and contains much less water vapor than near the ground, which means that adding more carbon dioxide significantly influences how much infrared radiation escapes to space.

Observing the greenhouse effect

Have you ever noticed that deserts are often colder at night than forests, even if their average temperatures are the same? Without much water vapor in the atmosphere over deserts, the radiation they give off escapes readily to space. In more humid regions radiation from the surface is trapped by water vapor in the air. Similarly, cloudy nights tend to be warmer than clear nights because more water vapor is present.

The influence of carbon dioxide can be seen in past changes in climate. Ice cores from over the past million years have shown that carbon dioxide concentrations were high during warm periods – about 0.028%. During ice ages, when the Earth was roughly 7 to 13 F (4-7 C) cooler than in the 20th century, carbon dioxide made up only about 0.018% of the atmosphere.

Even though water vapor is more important for the natural greenhouse effect, changes in carbon dioxide have driven past temperature changes. In contrast, water vapor levels in the atmosphere respond to temperature. As Earth becomes warmer, its atmosphere can hold more water vapor, which amplifies the initial warming in a process called the “water vapor feedback.” Variations in carbon dioxide have therefore been the controlling influence on past climate changes.

Small change, big effects

It shouldn’t be surprising that a small amount of carbon dioxide in the atmosphere can have a big effect. We take pills that are a tiny fraction of our body mass and expect them to affect us.

Today the level of carbon dioxide is higher than at any time in human history. Scientists widely agree that Earth’s average surface temperature has already increased by about 2 F (1 C) since the 1880s, and that human-caused increases in carbon dioxide and other heat-trapping gases are extremely likely to be responsible.

Without action to control emissions, carbon dioxide might reach 0.1% of the atmosphere by 2100, more than triple the level before the Industrial Revolution. This would be a faster change than transitions in Earth’s past that had huge consequences. Without action, this little sliver of the atmosphere will cause big problems.

See the full article here .

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Carolina’s vibrant people and programs attest to the University’s long-standing place among leaders in higher education since it was chartered in 1789 and opened its doors for students in 1795 as the nation’s first public university. Situated in the beautiful college town of Chapel Hill, N.C., UNC has earned a reputation as one of the best universities in the world. Carolina prides itself on a strong, diverse student body, academic opportunities not found anywhere else, and a value unmatched by any public university in the nation.

From Penn Today: “Researchers think small to make progress towards better fuel cells”

From Penn Today

September 13, 2019
Erica K. Brockmeier
Eric Sucar Photographer

A collaborative study describes how fuel cells, which use chemical energy to power cars and devices, can be developed using nanomaterials to be more cost-effective and efficient in the long term.

Graduate student Jennifer Lee uses a large transmission electron microscope, housed in the Singh Center, to take a closer look at the nanomaterials and nanocrystals that are synthesized in the lab.

As renewable sources such as wind and solar are quickly changing the energy landscape, scientists are looking for ways to better store energy for when it’s needed. Fuel cells, which convert chemical energy into electrical power, are one possible solution for long-term energy storage, and could someday be used to power trucks and cars without burning fuel. But before fuel cells can be widely used, chemists and engineers need to find ways to make this technology more cost-effective and stable.

A new study from the lab of Penn Integrates Knowledge Professor Christopher Murray, led by graduate student Jennifer Lee, shows how custom-designed nanomaterials can be used to address these challenges. In ACS Applied Materials & Interfaces, researchers show how a fuel cell can be built from cheaper, more widely available metals using an atomic-level design that also gives the material long-term stability. Former post-doc Davit Jishkariani and former students Yingrui Zhao and Stan Najmr, current student Daniel Rosen, and professors James Kikkawa and Eric Stach, also contributed to this work.

The chemical reaction that powers a fuel cell relies on two electrodes, a negative anode and a positive cathode, separated by an electrolyte, a substance that allows the ions to move. When fuel enters the anode, a catalyst separates molecules into protons and electrons, with the latter traveling toward the cathode and creating an electric current.

Catalysts are typically made of precious metals, like platinum, but because the chemical reactions only occur on the surface of the material, any atoms that are not presented on the surface of the material are wasted. It’s also important for catalysts to be stable for months and years because fuel cells are very difficult to replace.

Chemists can address these two problems by designing custom nanomaterials that have platinum at the surface while using more common metals, such as cobalt, in the bulk to provide stability. The Murray group excels at creating well-controlled nanomaterials, known as nanocrystals, in which they can control the size, shape, and composition of any composite nanomaterial.

When not busy at the microscope or analyzing data, researchers in the Murray group work on synthesizing new nanomaterials.

In this study, Lee focused on the catalyst in the cathode of a specific type of fuel cell known as a proton exchange membrane fuel cell. “The cathode is more of a problem, because the materials are either platinum or platinum-based, which are expensive and have slower reaction rates,” she says. “Designing the catalyst for the cathode is the main focus of designing a good fuel cell.”

The challenge, explains Jishkariani, was in creating a cathode in which platinum and cobalt atoms would form into a stable structure. “We know cobalt and platinum mixes well; however, if you make alloys of these two, you have added atoms of platinum and cobalt in a random order,” he says. Adding more cobalt in a random order causes it to leach out into the electrode, meaning that the fuel cell will only function for a short time.

To solve this problem, researchers designed a catalyst made of layered platinum and cobalt known as an intermetallic phase. By controlling exactly where each atom sat in the catalyst and locking the structure in place, the cathode catalyst was able to work for longer periods than when the atoms were arranged randomly. As an additional unexpected finding, the researchers found that adding more cobalt to the system led to greater efficiency, with a 1-to-1 ratio of platinum to cobalt, better than many other structures with a wide range of platinum-to-cobalt ratios.

The next step will be to test and evaluate the intermetallic material in fuel cell assemblies to make direct comparisons to commercially-available systems. The Murray group will also be working on new ways to create the intermetallic structure without high temperatures and seeing if adding additional atoms improve the catalyst’s performance.

The Xeuss 2.0 X-ray scattering instrument, which came to the LRSM in 2018, helps researchers characterize the structures of a wide range of hard and soft materials.

This work required high-resolution microscopic imaging, work that Lee previously did at Brookhaven National Lab but, thanks to recent acquisitions, can now be done at Penn in the Singh Center for Nanotechnology. “Many of the high-end experiments that we would have had to travel to around the country, sometimes around the world, we can now do much closer to home,” says Murray. “The advances that we’ve brought in electron microscopy and X-ray scattering are a fantastic addition for people that work on energy conversion and catalytic studies.”

Lee also experienced first-hand how chemistry research directly connects to real world challenges. She recently presented this work at the International Precious Metals Institute conference and says that meeting members of the precious-metals community was enlightening. “There are companies looking at fuel cell technology and talking about the newest design of the fuel cell cars,” she says. “You get to interact with people that think of your project from different perspectives.”

Murray sees this fundamental research as a starting point towards commercial implementation and real world application, emphasizing that future progress relies on the forward-looking research that’s happening now. “Thinking about a world where we’ve displaced a lot of the traditional fossil fuel-based inputs, if we can figure out this interconversion of electrical and chemical energy, that will address a couple of very important problems simultaneously.”

This research was supported by the U.S. Department of Energy Fuel Cell Technology Office. This research used resources of the Center for Functional Nanomaterials of the Brookhaven National Laboratory, supported by the U.S. Department of Energy Office of Science Graduate Student Research (SCGSR) program.

BNL Center for Functional Nanomaterials

Magnetic property measurements were supported by the National Science Foundation Materials Research Science and Engineering Center Grant DMR-1720530.

See the full article here .

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Academic life at Penn is unparalleled, with 100 countries and every U.S. state represented in one of the Ivy League’s most diverse student bodies. Consistently ranked among the top 10 universities in the country, Penn enrolls 10,000 undergraduate students and welcomes an additional 10,000 students to our world-renowned graduate and professional schools.

Penn’s award-winning educators and scholars encourage students to pursue inquiry and discovery, follow their passions, and address the world’s most challenging problems through an interdisciplinary approach.

From SLAC National Accelerator Lab: “Plastics, fuels and chemical feedstocks from CO2? They’re working on it.”

From SLAC National Accelerator Lab

September 9, 2019
Glennda Chui

Researchers at Stanford and SLAC are working on ways to convert waste carbon dioxide (CO2) into chemical feedstocks and fuels, turning a potent greenhouse gas into valuable products. The process is called electrochemical conversion. When powered by renewable energy sources (far left), it could reduce levels of carbon dioxide in the air and store energy from these intermittent sources in a form that can be used any time. (Greg Stewart/SLAC National Accelerator Laboratory)

One way to reduce the level of carbon dioxide in the atmosphere, which is now at its highest point in 800,000 years, would be to capture the potent greenhouse gas from the smokestacks of factories and power plants and use renewable energy to turn it into things we need, says Thomas Jaramillo.

As director of SUNCAT Center for Interface Science and Catalysis, a joint institute of Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, he’s in a position to help make that happen.

A major focus of SUNCAT research is finding ways to transform CO2 into chemicals, fuels, and other products, from methanol to plastics, detergents and synthetic natural gas. The production of these chemicals and materials from fossil fuel ingredients now accounts for 10% of global carbon emissions; the production of gasoline, diesel, and jet fuel accounts for much, much more.

“We have already emitted too much CO2, and we’re on track to continue emitting it for years, since 80% of the energy consumed worldwide today comes from fossil fuels,” says Stephanie Nitopi, whose SUNCAT research is the basis of her newly acquired Stanford PhD.

“You could capture CO2 from smokestacks and store it underground,” she says. “That’s one technology currently in play. An alternative is to use it as a feedstock to make fuels, plastics, and specialty chemicals, which shifts the financial paradigm. Waste CO2 emissions now become something you can recycle into valuable products, providing a new incentive to reduce the amount of CO2 released into the atmosphere. That’s a win-win.”

We asked Nitopi, Jaramillo, SUNCAT staff scientist Christopher Hahn and postdoctoral researcher Lei Wang to tell us what they’re working on and why it matters.

Q. First the basics: How do you convert CO2 into these other products?

Tom: It’s essentially a form of artificial photosynthesis, which is why DOE’s Joint Center for Artificial Photosynthesis funds our work. Plants use solar energy to convert CO2 from the air into carbon in their tissues. Similarly, we want to develop technologies that use renewable energy, like solar or wind, to convert CO2 from industrial emissions into carbon-based products.

Chris: One way to do this is called electrochemical CO2 reduction, where you bubble CO2 gas up through water and it reacts with the water on the surface of a copper-based electrode. The copper acts as a catalyst, bringing the chemical ingredients together in a way that encourages them to react. Put very simply, the initial reaction strips an oxygen atom from CO2 to form carbon monoxide, or CO, which is an important industrial chemical in its own right. Then other electrochemical reactions turn CO into important molecules such as alcohols, fuels and other things.

Today this process requires a copper-based catalyst. It’s the only one known to do the job. But these reactions can produce numerous products, and separating out the one you want is costly, so we need to identify new catalysts that are able to guide the reaction toward making only the desired product.

How so?

Lei: When it comes to improving a catalyst’s performance, one of the key things we look at is how to make them more selective, so they generate just one product and nothing else. About 90 percent of fuel and chemical manufacturing depends on catalysts, and getting rid of unwanted byproducts is a big part of the cost.

We also look at how to make catalysts more efficient by increasing their surface area, so there are a lot more places in a given volume of material where reactions can occur simultaneously. This increases the production rate.

Recently we discovered something surprising [Nature Catalysis]: When we increased the surface area of a copper-based catalyst by forming it into a flaky “nanoflower” shape, it made the reaction both more efficient and more selective. In fact, it produced virtually no byproduct hydrogen gas that we could measure. So this could offer a way to tune reactions to make them more selective and cost-competitive.

Stephanie: This was so surprising that we decided to revisit all the research we could find [Chem. Rev.] on catalyzing electrochemical CO2 conversion with copper, and the many ways people have tried to understand and fine-tune the process, using both theory and experiments, going back four decades. There’s been an explosion of research on this – about 60 papers had been published as of 2006, versus more than 430 out there today – and analyzing all the studies with our collaborators at the Technical University of Denmark took two years.

We were trying to figure out what makes copper special, why it’s the only catalyst that can make some of these interesting products, and how we can make it even more efficient and selective – what techniques have actually pushed the needle forward? We also offered our perspectives on promising research directions.

One of our conclusions confirms the results of the earlier study: The copper catalyst’s surface area can be used to improve both the selectivity and overall efficiency of reactions. So this is well worth considering as a chemical production strategy.

Does this approach have other benefits?

Tom: Absolutely. If we use clean, renewable energy, like wind or solar, to power the controlled conversion of waste CO2 to a wide range of other products, this could actually draw down levels of CO2 in the atmosphere, which we will need to do to stave off the worst effects of global climate change.

Chris: And when we use renewable energy to convert CO2 to fuels, we’re storing the variable energy from those renewables in a form that can be used any time. In addition, with the right catalyst, these reactions could take place at close to room temperature, instead of the high temperatures and pressures often needed today, making them much more energy efficient.

How close are we to making it happen?

Tom: Chris and I explored this question in a recent Perspective article in Science, written with researchers from the University of Toronto and TOTAL American Services, which is an oil and gas exploration and production services firm.

We concluded that renewable energy prices would have to fall below 4 cents per kilowatt hour, and systems would need to convert incoming electricity to chemical products with at least 60% efficiency, to make the approach economically competitive with today’s methods.

Chris: This switch couldn’t happen all at once; the chemical industry is too big and complex for that. So one approach would be to start with making high-value, high-volume products like ethylene, which is used to make alcohols, polyester, antifreeze, plastics and synthetic rubber. It’s a $230 billion global market today. Switching from fossil fuels to CO2 as a starting ingredient for ethylene in a process powered by renewables could potentially save the equivalent of about 860 million metric tons of CO2 emissions per year.

The same step-by-step approach applies to sources of CO2. Industry could initially use relatively pure CO2 emissions from cement plants, breweries or distilleries, for instance, and this would have the side benefit of decentralizing manufacturing. Every country could provide for itself, develop the technology it needs, and give its people a better quality of life.

Tom: Once you enter certain markets and start scaling up the technology, you can attack other products that are tougher to make competitively today. What this paper concludes is that these new processes have a chance to change the world.

See the full article here .

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SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From Stanford University: “Stanford chemists discover water microdroplets spontaneously produce hydrogen peroxide”

From Stanford University

August 26, 2019
Nathan Collins, Stanford News Service
(650) 228-4677
nac@stanford.edu

Despite its abundance, water retains a great many secrets. Among them, Stanford chemists have discovered, is that water microdroplets spontaneously produce hydrogen peroxide.

Water is everywhere on Earth, but maybe that just gives it more space to hide its secrets. Its latest surprise, Stanford researchers report Aug. 26 in Proceedings of the National Academy of Sciences, is that microscopic droplets of water spontaneously produce hydrogen peroxide.

Chemistry Professor Richard Zare and his lab have shown that water microdroplets spontaneously – and unexpectedly – produce hydrogen peroxide. (Image credit: L.A. Cicero)

The discovery could pave the way for greener ways to produce the molecule, a common bleaching agent and disinfectant, said Richard Zare, the Marguerite Blake Wilbur Professor in Natural Science and a professor of chemistry in the Stanford School of Humanities and Sciences.

“Water is one of the most commonly found materials, and it’s been studied for years and years and you would think that there was nothing more to learn about this molecule. But here’s yet another surprise,” said Zare, who is also a member of Stanford Bio-X.

The discovery was made serendipitously while Zare and his lab were studying a new, more efficient way to create gold nanostructures in tiny water droplets known as microdroplets. To make those structures, the team added an additional molecule called a reducing agent. As a control test, Zare suggested seeing if they could create gold nanostructures without the reducing agent. Theoretically that should have been impossible, but it worked anyway – hinting at an as yet undiscovered feature of microdroplet chemistry.

The team eventually traced those results to the presence of a molecule called hydroxyl – a single hydrogen atom paired with an oxygen atom – that can also act as a reducing agent. That equally unexpected result led Katherine Walker, at the time a graduate student in Zare’s lab, to wonder whether hydrogen peroxide – a molecule with two hydrogen and two oxygen atoms – was also present.

To find out, Zare, Walker, staff scientist Jae Kyoo Lee and colleagues conducted a series of tests, the simplest of which involved spraying ostensibly pure water microdroplets onto a surface treated so that it would turn blue in the presence of hydrogen peroxide – and turn blue it did. Additional tests confirmed that water microdroplets spontaneously form hydrogen peroxide, that smaller microdroplets produced higher concentrations of the molecule, and that hydrogen peroxide was not lost when the microdroplets recombined into bulk water.

Video by Jae Kyoo Lee and Hyun Soo Han

In this demonstration, a test strip turns blue when sprayed with water microdroplets, indicating the presence of hydrogen peroxide.

The researchers ruled out a number of possible explanations before arriving at what they argue is the most likely explanation for hydrogen peroxide’s presence. They suggest that a strong electric field near the surface of water microdroplets in air triggers hydroxyl molecules to bind into hydrogen peroxide.

Although the results are something of a basic science curiosity, Zare said, they could have important practical consequences. Hydrogen peroxide is an important commercial and industrial chemical, most often manufactured through an ecologically unfriendly process. The new discovery could help make those methods greener, Zare said, and it could lead to simpler ways to disinfect surfaces – simply spraying water microdroplets on a table or floor might be enough to clean it.

“I think it could be one of the most important things I’ve ever done,” Zare said.

Additional authors include Robert Waymouth, the Robert Eckles Swain Professor in Chemistry; Friedrich Prinz, the Finmeccanica Professor and a professor of mechanical engineering and of materials science and engineering; postdoctoral fellow Hyun Soo Han; and researchers from the Institute for Basic Science and the Daegu Gyeongbuk Institute of Science and Technology.

Zare is also a member of the Cardiovascular Institute, the Stanford Cancer Institute, Stanford ChEM-H, the Stanford Woods Institute for the Environment and the Wu Tsai Neurosciences Institute.

The research was funded in part by a grant from the U.S. Air Force Office of Scientific Research and the Institute for Basic Science, South Korea.

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Stanford University

Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

From Rice University: “Rice reactor turns greenhouse gas into pure liquid fuel”

From Rice University

September 3, 2019
Mike Williams
713-348-6728
mikewilliams@rice.edu

Lab’s ‘green’ invention reduces carbon dioxide into valuable fuels.

Rice postdoctoral researcher Chuan Xia, left, and chemical and biomolecular engineer Haotian Wang adjust their electrocatalysis reactor to produce liquid formic acid from carbon dioxide. Photo by Jeff Fitlow

A common greenhouse gas could be repurposed in an efficient and environmentally friendly way with an electrolyzer that uses renewable electricity to produce pure liquid fuels.

The catalytic reactor developed by the Rice University lab of chemical and biomolecular engineer Haotian Wang uses carbon dioxide as its feedstock and, in its latest prototype, produces highly purified and high concentrations of formic acid.

Formic acid produced by traditional carbon dioxide devices needs costly and energy-intensive purification steps, Wang said. The direct production of pure formic acid solutions will help to promote commercial carbon dioxide conversion technologies.

The method is detailed in Nature Energy.

Wang, who joined Rice’s Brown School of Engineering in January, and his group pursue technologies that turn greenhouse gases into useful products. In tests, the new electrocatalyst reached an energy conversion efficiency of about 42%. That means nearly half of the electrical energy can be stored in formic acid as liquid fuel.

“Formic acid is an energy carrier,” Wang said. “It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide — which you can grab and recycle again.

“It’s also fundamental in the chemical engineering industry as a feedstock for other chemicals, and a storage material for hydrogen that can hold nearly 1,000 times the energy of the same volume of hydrogen gas, which is difficult to compress,” he said. “That’s currently a big challenge for hydrogen fuel-cell cars.”

This schematic shows the electrolyzer developed at Rice to reduce carbon dioxide, a greenhouse gas, to valuable fuels. At left is a catalyst that selects for carbon dioxide and reduces it to a negatively charged formate, which is pulled through a gas diffusion layer (GDL) and the anion exchange membrane (AEM) into the central electrolyte. At the right, an oxygen evolution reaction (OER) catalyst generates positive protons from water and sends them through the cation exchange membrane (CEM). The ions recombine into formic acid or other products that are carried out of the system by deionized (DI) water and gas. Illustration by Chuan Xia and Demin Liu.

Two advances made the new device possible, said lead author and Rice postdoctoral researcher Chuan Xia. The first was his development of a robust, two-dimensional bismuth catalyst and the second a solid-state electrolyte that eliminates the need for salt as part of the reaction.

“Bismuth is a very heavy atom, compared to transition metals like copper, iron or cobalt,” Wang said. “Its mobility is much lower, particularly under reaction conditions. So that stabilizes the catalyst.” He noted the reactor is structured to keep water from contacting the catalyst, which also helps preserve it.

Xia can make the nanomaterials in bulk. “Currently, people produce catalysts on the milligram or gram scales,” he said. “We developed a way to produce them at the kilogram scale. That will make our process easier to scale up for industry.”

Rice postdoctoral researcher Chuan Xia, left, and chemical and biomolecular engineer Haotian Wang. Photo by Jeff Fitlow

The polymer-based solid electrolyte is coated with sulfonic acid ligands to conduct positive charge or amino functional groups to conduct negative ions. “Usually people reduce carbon dioxide in a traditional liquid electrolyte like salty water,” Wang said. “You want the electricity to be conducted, but pure water electrolyte is too resistant. You need to add salts like sodium chloride or potassium bicarbonate so that ions can move freely in water.

“But when you generate formic acid that way, it mixes with the salts,” he said. “For a majority of applications you have to remove the salts from the end product, which takes a lot of energy and cost. So we employed solid electrolytes that conduct protons and can be made of insoluble polymers or inorganic compounds, eliminating the need for salts.”

The rate at which water flows through the product chamber determines the concentration of the solution. Slow throughput with the current setup produces a solution that is nearly 30% formic acid by weight, while faster flows allow the concentration to be customized. The researchers expect to achieve higher concentrations from next-generation reactors that accept gas flow to bring out pure formic acid vapors.

The Rice lab worked with Brookhaven National Laboratory to view the process in progress. “X-ray absorption spectroscopy, a powerful technique available at the Inner Shell Spectroscopy (ISS) beamline at Brookhaven Lab’s National Synchrotron Light Source II, enables us to probe the electronic structure of electrocatalysts in operando — that is, during the actual chemical process,” said co-author Eli Stavitski, lead beamline scientist at ISS. “In this work, we followed bismuth’s oxidation states at different potentials and were able to identify the catalyst’s active state during carbon dioxide reduction.”

BNL NSLS II

With its current reactor, the lab generated formic acid continuously for 100 hours with negligible degradation of the reactor’s components, including the nanoscale catalysts. Wang suggested the reactor could be easily retooled to produce such higher-value products as acetic acid, ethanol or propanol fuels.

An electrocatalysis reactor built at Rice recycles carbon dioxide to produce pure liquid fuel solutions using electricity. The scientists behind the invention hope it will become an efficient and profitable way to reuse the greenhouse gas and keep it out of the atmosphere. Photo by Jeff Fitlow

“The big picture is that carbon dioxide reduction is very important for its effect on global warming as well as for green chemical synthesis,” Wang said. “If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it.”

Co-authors are Rice graduate student Peng Zhu; graduate student Qiu Jiang and Husam Alshareef, a professor of material science and engineering, at King Abdullah University of Science and Technology, Saudi Arabia (KAUST); postdoctoral researcher Ying Pan of Harvard University; and staff scientist Wentao Liang of Northeastern University. Wang is the William Marsh Rice Trustee Assistant Professor of Chemical and Biomolecular Engineering. Xia is a J. Evans Attwell-Welch Postdoctoral Fellow at Rice.

Rice and the U.S. Department of Energy Office of Science User Facilities supported the research.

Eli Stavitski, lead scientist at the Inner Shell Spectroscopy (ISS) beamline at Brookhaven National Laboratory’s National Synchrotron Light Source II, used the powerful tool to probe bismuth’s oxidation states, part of the process developed at Rice University to recycle carbon dioxide to produce pure liquid fuel solutions using electricity. (Credit: Brookhaven National Laboratory)

See the full article here .

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Stem Education Coalition

In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

From Lawrence Berkeley National Lab: “Study Reveals ‘Radical’ Wrinkle in Forming Complex Carbon Molecules in Space”

From Lawrence Berkeley National Lab

September 3, 2019
Glenn Roberts Jr.
geroberts@lbl.gov
(510) 486-5582

This composite image shows an illustration of a carbon-rich red giant star (middle) warming an exoplanet (bottom left) and an overlay of a newly found pathway that could enable complex carbons to form near these stars. (Credits: ESO/L. Calçada; Berkeley Lab, Florida International University, and University of Hawaii at Manoa)

A team of scientists has discovered a new possible pathway toward forming carbon structures in space using a specialized chemical exploration technique at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

The team’s research has now identified several avenues by which ringed molecules known as polycyclic aromatic hydrocarbons, or PAHs, can form in space. The latest study is a part of an ongoing effort to retrace the chemical steps leading to the formation of complex carbon-containing molecules in deep space.

PAHs – which also occur on Earth in emissions and soot from the combustion of fossil fuels – could provide clues to the formation of life’s chemistry in space as precursors to interstellar nanoparticles. They are estimated to account for about 20 percent of all carbon in our galaxy, and they have the chemical building blocks needed to form 2D and 3D carbon structures.

In the latest study, published in Nature Communications, researchers produced a chain of ringed, carbon-containing molecules by combining two highly reactive chemical species that are called free radicals because they contain unpaired electrons. The study ultimately showed how these chemical processes could lead to the development of carbon-containing graphene-type PAHs and 2D nanostructures. Graphene is a one-atom-thick layer of carbon atoms.

Importantly, the study showed a way to connect a five-sided (pentagon-shaped) molecular ring with a six-sided (hexagonal) molecular ring and to also convert five-sided molecular rings to six-sided rings, which is a stepping stone to a broader range of large PAH molecules.

“This is something that people have tried to measure experimentally at high temperatures but have not done before,” said Musahid Ahmed, a scientist in Berkeley Lab’s Chemical Sciences Division. He led the chemical-mixing experiments at Berkeley Lab’s Advanced Light Source (ALS) with Professor Ralf I. Kaiser at the University of Hawaii at Manoa.

LBNL ALS

“We believe this is yet another pathway that can give rise to PAHs.”

Professor Alexander M. Mebel at Florida International University assisted in the computational work for the study. Previous studies by the same research team have also identified a couple of other pathways for PAHs to develop in space. The studies suggest there could be multiple chemical routes for life’s chemistry to take shape in space.

“It could be all the above, so that it isn’t just one,” Ahmed said. “I think that’s what makes this interesting.”

The experiments at Berkeley Lab’s ALS – which produces X-rays and other types of light supporting many different types of simultaneous experiments – used a portable chemical reactor that combines chemicals and then jets them out to study what reactants formed in the heated reactor.

Researchers used a light beam tuned to a wavelength known as “vacuum ultraviolet” or VUV produced by the ALS, coupled with a detector (called a reflectron time-of-flight mass spectrometer), to identify the chemical compounds jetting out of the reactor at supersonic speeds.

The latest study combined the chemical radicals CH3 (aliphatic methyl radical) with C9H7 (aromatic 1-indenyl radical) at a temperature of about 2,105 Fahrenheit degrees to ultimately produce molecules of a PAH known as naphthalene (C10H8) that is composed of two joined benzene rings.

The conditions required to produce naphthalene in space are present in the vicinity of carbon-rich stars, the study noted.

The reactants produced from two radicals, the study notes, had been theorized but hadn’t been demonstrated before in a high-temperature environment because of experimental challenges.

“The radicals are short-lived – they react with themselves and react with anything else around them,” Ahmed said. “The challenge is, ‘How do you generate two radicals at the same time and in the same place, in an extremely hot environment?’ We heated them up in the reactor, they collided and formed the compounds, and then we expelled them out of the reactor.”

Kaiser said, “For several decades, radical-radical reactions have been speculated to form aromatic structures in combustion flames and in deep space, but there has not been much evidence to support this hypothesis.” He added, “The present experiment clearly provides scientific evidence that reactions between radicals at elevated temperatures do form aromatic molecules such as naphthalene.”

While the method used in this study sought to detail how specific types of chemical compounds form in space, the researchers noted that the methods used can also enlighten broader studies of chemical reactions involving radicals exposed to high temperatures, such as in the fields of materials chemistry and materials synthesis.

Researchers at Berkeley Lab, the University of Hawaii at Manoa, and Florida International University participated in this study. The work was supported by the U.S. Department of Energy Office of Science’s Basic Energy Sciences program and a Presidential Fellowship at Florida International University.

The Advanced Light Source is a DOE Office of Science User Facility.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

LBNL campus

Bringing Science Solutions to the World
In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

A U.S. Department of Energy National Laboratory Operated by the University of California.

From University of Rochester: “A ‘new chapter’ in quest for novel quantum materials”

From University of Rochester

August 27, 2019
Bob Marcotte
bmarcotte@ur.rochester.edu

Diamond anvil cells are used to compress and alter the properties of hydrogen rich materials in the lab of assistant professor Ranga Dias. Rochester scientists like Dias are working to uncover the remarkable quantum properties of materials. (University of Rochester photo / J. Adam Fenster)

In an oven, aluminum is remarkable because it can serve as foil over a casserole without ever becoming hot itself.

However, put aluminum in a crucible of extraordinarily high pressure, blast it with high-powered lasers like those at the Laboratory for Laser Energetics, and even more remarkable things happen. Aluminum stops being a metal. It even turns transparent.

University of Rochester Laboratory for Laser Energetics

U Rochester The main amplifiers at the OMEGA EP laser at the University of Rochester’s Laboratory for Laser Energetics

Exactly how and why this occurs is not yet clear. However, LLE scientists and their collaborators say a $4 million grant—from the Quantum Information Science Research for Fusion Energy Sciences (QIS) program within the Department of Energy’s Office of Fusion Energy Science [see the separate article]—will help them better understand and apply the quantum (subatomic) phenomena that cause materials to be transformed at pressures more than a million—even a billion—times the atmospheric pressure on Earth.”

The potential dividends are huge, including:

Superfast quantum computers immune to hacking

IBM iconic image of Quantum computer

Cheap energy created from fusion and delivered over superconducting wires.

PPPL LTX Lithium Tokamak Experiment

A more secure stockpile of nuclear weapons as a deterrent.

A better understanding of how planets and other astronomical bodies form – and even whether some might be habitable.

A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

“This three-year effort, led by the University of Rochester, will leverage world-class expertise and facilities, and open a new chapter of quantum matter exploration,” says lead investigator Gilbert “Rip” Collins, who heads the University’s high energy density physics program. The project also includes researchers from the University of Illinois at Chicago, the University of Buffalo, the University of Utah, and Howard University and collaborators at the Lawrence Livermore National Laboratory and the University of Edinburgh.

The chief players in quantum mechanics are electrons, protons, photons, and other subatomic particles. Quantum mechanics prescribe only discrete energies or speeds for electrons. These particles can also readily exhibit “duality”—at times acting like distinct particles, at other times taking on wave-like characteristics as well.

However, until recently a lot of their quantum behaviors and properties could be observed only at extremely low, cryogenic temperatures. At low temperatures, the wave-like behavior causes electrons, in layperson terms, “to overlap, become more social and talk more to their neighbors all while occupying discrete states,” says Mohamed Zaghoo, an LLE scientist and project team member. This quantum behavior allows them to transmit energy and can result in superconductive materials.

“The new realization is that you can achieve the same type of ‘quantumness’ of particles if you compress them really, really tightly,” Zaghoo says. This can be achieved in various ways, from blasting the materials with powerful, picoseconds laser bursts to slowly compressing them for days, even months between super-hard industrial diamonds in nanoscale “anvils.”

“Now you can say these materials can only exist under really high pressures, so to duplicate that under normal conditions is still a challenge,” Zaghoo concedes. “But if we are able to understand why materials acquire these exotic behaviors at really high pressures, maybe we can tweak the parameters, and design materials that have these same quantum properties at both higher temperatures and lower pressures. We also hope to build a predictive theory about why and how certain kinds of elements can have these quantum properties and others don’t.”

Here’s an example of why this is an exciting prospect for Zaghoo and his collaborators. Aluminum not only becomes transparent, but also loses its ability to conduct energy at extremely high pressure. If it happens to aluminum, it’s likely it will happen with other metals as well. Chips and transistors rely on metallic oxides to serve as insulating layers. And so, the ability to use high pressure to “uniquely tune” the quantum properties of various metals could lead to “new types of oxides, new types of conductors that make the circuits much more efficient, and lose less heat,” Zaghoo says.

“We would be able to design better electronics.”

And that could help address concerns that Moore’s law—which states the number of transistors in a dense integrated circuit doubles about every two years—cannot continue to be sustained using existing materials and circuitry.

U Rochester a leader in high energy density physics

In addition to creating new materials, a major thrust of the project is to be able to describe and explore those materials in meaningful ways.

“The instrumentation and diagnostics are not there yet,” Zaghoo says. So, part of the proposal is to develop new techniques to “look at these materials and actually see something of substance.”

Much of the project will be done at LLE and at affiliated labs in the University’s Department of Mechanical Engineering. Those labs are led by Ranga Dias, an assistant professor who uses diamond anvil cells to compress hydrogen-rich materials, and Niaz Abdolrahim, an assistant professor who uses computational techniques to understand the deformation of nanoscale metals and other materials.

However, the lab of Russell Hemley at the University of Illinois at Chicago, for example, will also assist the effort to synthesize new materials using diamonds. And Eva Zurek at the SUNY University at Buffalo will be in charge of developing new theoretical models to describe the quantum behaviors that lead to new materials.

“Our scientific team is both diverse and contains top leaders in the fields of high-energy density science, emergent quantum materials, plasmas, condensed matter and computations,” says Collins. “Extensive outreach, workshops and high-profile publications resulting from this work will engage a world-wide community in this extreme quantum revolution.”

Established in 1970 to investigate the interaction of intense radiation with matter, LLE has played a leading role in the quest to achieve nuclear fusion in the lab, with a particular emphasis on inertial confinement fusion.

Two years ago, it launched its high energy density physics initiative under the leadership of Collins, who had previously directed Lawrence Livermore National Laboratory’s Center for High Energy Density Physics.

In addition to drawing upon LLE’s scientists and facilities, the program has also benefited from close collaborations with engineering and science faculty and their students on the University’s nearby River Campus. The synergy has resulted in numerous grants and papers.

See the full article here .

See also the earlier article Department of Energy awards $4 million to University’s Extreme Quantum Team.

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Please help promote STEM in your local schools.

Stem Education Coalition

The University of Rochester is one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.

Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.

From University of Washington: “Scientists can now control thermal profiles at the nanoscale”

From University of Washington

August 9, 2019
James Urton

Handwritten notes from David J. Masiello, associate professor of chemistry at the University of WashingtonDavid J. Masiello / U. of Washington

At human scale, controlling temperature is a straightforward concept. Turtles sun themselves to keep warm. To cool a pie fresh from the oven, place it on a room-temperature countertop.

At the nanoscale — at distances less than 1/100th the width of the thinnest human hair — controlling temperature is much more difficult. Nanoscale distances are so small that objects easily become thermally coupled: If one object heats up to a certain temperature, so does its neighbor.

When scientists use a beam of light as that heat source, there is an additional challenge: Thanks to heat diffusion, materials in the beam path heat up to approximately the same temperature, making it difficult to manipulate the thermal profiles of objects within the beam. Scientists have never been able to use light alone to actively shape and control thermal landscapes at the nanoscale.

At least, not until now.

In a paper published online July 30 by the journal ACS Nano, a team of researchers reports that they have designed and tested an experimental system that uses a near-infrared laser to actively heat two gold nanorod antennae — metal rods designed and built at the nanoscale — to different temperatures. The nanorods are so close together that they are both electromagnetically and thermally coupled. Yet the team, led by researchers at the University of Washington, Rice University and Temple University, measured temperature differences between the rods as high as 20 degrees Celsius. By simply changing the wavelength of the laser, they could also change which nanorod was cooler and which was warmer, even though the rods were made of the same material.

“If you put two similar objects next to each other on a table, ordinarily you would expect them to be at the same temperature. The same is true at the nanoscale,” said lead corresponding author David Masiello, a UW professor of chemistry and faculty member in both the Molecular & Engineering Sciences Institute and the Institute for Nano-Engineered Systems. “Here, we can expose two coupled objects of the same material composition to the same beam, and one of those objects will be warmer than the other.”

Masiello’s team performed the theoretical modeling to design this system. He partnered with co-corresponding authors Stephan Link, a professor of both chemistry and electrical and computer engineering at Rice University, and Katherine Willets, an associate professor of chemistry at Temple University, to build and test it.

Their system consisted of two nanorods made of gold — one 150 nanometers long and the other 250 nanometers long, or about 100 times thinner than the thinnest human hair. The researchers placed the nanorods close together, end to end on a glass slide surrounded by glycerol.

This figure shows evidence that the two nanorods were heated to different temperatures. The researchers collected data on how the heated nanorods and surrounding glycerol scattered photons from a beam of green light. The five graphs show the intensity of that scattered light at five different wavelengths, and insets show images of the scattered light. Arrows indicate that peak intensity shifts at different wavelengths, an indirect sign that the nanorods were heated to different temperatures.Bhattacharjee et al., ACS Nano, 2019.

They chose gold for a specific reason. In response to sources of energy like a near-infrared laser, electrons within gold can “oscillate” easily. These electronic oscillations, or surface plasmon resonances, efficiently convert light to heat. Though both nanorods were made of gold, their differing size-dependent plasmonic polarizations meant that they had different patterns of electron oscillations. Masiello’s team calculated that, if the nanorod plasmons oscillated with either the same or opposite phases, they could reach different temperatures — countering the effects of thermal diffusion.

Link’s and Willets’ groups designed the experimental system and tested it by shining a near-infrared laser on the nanorods. They studied the beam’s effect at two wavelengths — one for oscillating the nanorod plasmons with the same phase, another for the opposite phase.

The team could not directly measure the temperature of each nanorod at the nanoscale. Instead, they collected data on how the heated nanorods and surrounding glycerol scattered photons from a separate beam of green light. Masiello’s team analyzed those data and discovered that the nanorods refracted photons from the green beam differently due to nanoscale differences in temperature between the nanorods.

“This indirect measurement indicated that the nanorods had been heated to different temperatures, even though they were exposed to the same near-infrared beam and were close enough to be thermally coupled,” said co-lead author Claire West, a UW doctoral candidate in the Department of Chemistry.

The team also found that, by changing the wavelength of near-infrared light, they could change which nanorod — short or long — heated up more. The laser could essentially act as a tunable “switch,” changing the wavelength to alter which nanorod was hotter. The temperature differences between the nanorods also varied based on their distance apart, but reached as high as 20 degrees Celsius above room temperature.

The team’s findings have a range of applications based on controlling temperature at the nanoscale. For example, scientists could design materials that photo-thermally control chemical reactions with nanoscale precision, or temperature-triggered microfluidic channels for filtering tiny biological molecules.

The researchers are working to design and test more complex systems, such as clusters and arrays of nanorods. These require more intricate modeling and calculations. But given the progress to date, Masiello is optimistic that this unique partnership between theoretical and experimental research groups will continue to make progress.

“It was a team effort, and the results were years in the making, but it worked,” said Masiello.

West’s co-lead authors on the paper are Ujjal Bhattacharjee, a former researcher at Rice University now at the Indian Institute of Engineering Science and Technology, Shibpur, and Seyyed Ali Hosseini Jebeli, a researcher at Rich University. Co-authors are Harrison Goldwyn and Elliot Beutler, both doctoral students in the UW Department of Chemistry; Xiang-Tian Kong and Zhongwei Hu, both research associates in the UW Department of Chemistry; and Wei-Shun Chang, a former research scientist at Rice, now an assistant professor of chemistry and biochemistry at the University of Massachusetts Dartmouth. The research was funded by the National Science Foundation, the Robert A. Welch Foundation, and the University of Washington.

For more information, contact Masiello at 206-543-5579 or masiello@uw.edu.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

From MIT News: “New type of electrolyte could enhance supercapacitor performance”

From MIT News

August 12, 2019
David L. Chandler

Large anions with long tails (blue) in ionic liquids can make them self-assemble into sandwich-like bilayer structures on electrode surfaces. Ionic liquids with such structures have much improved energy storage capabilities. Image: Xianwen Mao, MIT

Novel class of “ionic liquids” may store more energy than conventional electrolytes — with less risk of catching fire.

Supercapacitors, electrical devices that store and release energy, need a layer of electrolyte — an electrically conductive material that can be solid, liquid, or somewhere in between. Now, researchers at MIT and several other institutions have developed a novel class of liquids that may open up new possibilities for improving the efficiency and stability of such devices while reducing their flammability.

“This proof-of-concept work represents a new paradigm for electrochemical energy storage,” the researchers say in their paper describing the finding, which appears today in the journal Nature Materials.

For decades, researchers have been aware of a class of materials known as ionic liquids — essentially, liquid salts — but this team has now added to these liquids a compound that is similar to a surfactant, like those used to disperse oil spills. With the addition of this material, the ionic liquids “have very new and strange properties,” including becoming highly viscous, says MIT postdoc Xianwen Mao PhD ’14, the lead author of the paper.

“It’s hard to imagine that this viscous liquid could be used for energy storage,” Mao says, “but what we find is that once we raise the temperature, it can store more energy, and more than many other electrolytes.”

That’s not entirely surprising, he says, since with other ionic liquids, as temperature increases, “the viscosity decreases and the energy-storage capacity increases.” But in this case, although the viscosity stays higher than that of other known electrolytes, the capacity increases very quickly with increasing temperature. That ends up giving the material an overall energy density — a measure of its ability to store electricity in a given volume — that exceeds those of many conventional electrolytes, and with greater stability and safety.

The key to its effectiveness is the way the molecules within the liquid automatically line themselves up, ending up in a layered configuration on the metal electrode surface. The molecules, which have a kind of tail on one end, line up with the heads facing outward toward the electrode or away from it, and the tails all cluster in the middle, forming a kind of sandwich. This is described as a self-assembled nanostructure.

“The reason why it’s behaving so differently” from conventional electrolytes is because of the way the molecules intrinsically assemble themselves into an ordered, layered structure where they come in contact with another material, such as the electrode inside a supercapacitor, says T. Alan Hatton, a professor of chemical engineering at MIT and the paper’s senior author. “It forms a very interesting, sandwich-like, double-layer structure.”

This highly ordered structure helps to prevent a phenomenon called “overscreening” that can occur with other ionic liquids, in which the first layer of ions (electrically charged atoms or molecules) that collect on an electrode surface contains more ions than there are corresponding charges on the surface. This can cause a more scattered distribution of ions, or a thicker ion multilayer, and thus a loss of efficiency in energy storage; “whereas with our case, because of the way everything is structured, charges are concentrated within the surface layer,” Hatton says.

The new class of materials, which the researchers call SAILs, for surface-active ionic liquids, could have a variety of applications for high-temperature energy storage, for example for use in hot environments such as in oil drilling or in chemical plants, according to Mao. “Our electrolyte is very safe at high temperatures, and even performs better,” he says. In contrast, some electrolytes used in lithium-ion batteries are quite flammable.

The material could help to improve performance of supercapacitors, Mao says. Such devices can be used to store electrical charge and are sometimes used to supplement battery systems in electric vehicles to provide an extra boost of power. Using the new material instead of a conventional electrolyte in a supercapacitor could increase its energy density by a factor of four or five, Mao says. Using the new electrolyte, future supercapacitors may even be able to store more energy than batteries, he says, potentially even replacing batteries in applications such as electric vehicles, personal electronics, or grid-level energy storage facilities.

The material could also be useful for a variety of emerging separation processes, Mao says. “A lot of newly developed separation processes require electrical control,” in various chemical processing and refining applications and in carbon dioxide capture, for example, as well as resource recovery from waste streams. These ionic liquids, being highly conductive, could be well-suited to many such applications, he says.

The material they initially developed is just an example of a variety of possible SAIL compounds. “The possibilities are almost unlimited,” Mao says. The team will continue to work on different variations and on optimizing its parameters for particular uses. “It might take a few months or years,” he says, “but working on a new class of materials is very exciting to do. There are many possibilities for further optimization.”

The research team included Paul Brown, Yinying Ren, Agilio Padua, and Margarida Costa Gomes at MIT; Ctirad Cervinka at École Normale Supérieure de Lyon, in France; Gavin Hazell and Julian Eastoe at the University of Bristol, in the U.K.; Hua Li and Rob Atkin at the University of Western Australia; and Isabelle Grillo at the Institut Max-von-Laue-Paul-Langevin in Grenoble, France. The researchers dedicate their paper to the memory of Grillo, who recently passed away.

“It is a very exciting result that surface-active ionic liquids (SAILs) with amphiphilic structures can self-assemble on electrode surfaces and enhance charge storage performance at electrified surfaces,” says Yi Cui, a professor of materials science and engineering at Stanford University, who was not associated with this research. “The authors have studied and understood the mechanism. The work here might have a great impact on the design of high energy density supercapacitors, and could also help improve battery performance,” he says.

Nicholas Abbott, the Tisch University Professor at Cornell University, who also was not involved in this work, says “The paper describes a very clever advance in interfacial charge storage, elegantly demonstrating how knowledge of molecular self-assembly at interfaces can be leveraged to address a contemporary technological challenge.”

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.