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      in Energy

      With just a little electricity, MIT researchers boost common catalytic reactions

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      A simple technique that uses small amounts of energy could boost the efficiency of some key chemical processing reactions, by up to a factor of 100,000, MIT researchers report. These reactions are at the heart of petrochemical processing, pharmaceutical manufacturing, and many other industrial chemical processes.

      The surprising findings are reported today in the journal Science, in a paper by MIT graduate student Karl Westendorff, professors Yogesh Surendranath and Yuriy Roman-Leshkov, and two others.

      “The results are really striking,” says Surendranath, a professor of chemistry and chemical engineering. Rate increases of that magnitude have been seen before but in a different class of catalytic reactions known as redox half-reactions, which involve the gain or loss of an electron. The dramatically increased rates reported in the new study “have never been observed for reactions that don’t involve oxidation or reduction,” he says.

      The non-redox chemical reactions studied by the MIT team are catalyzed by acids. “If you’re a first-year chemistry student, probably the first type of catalyst you learn about is an acid catalyst,” Surendranath says. There are many hundreds of such acid-catalyzed reactions, “and they’re super important in everything from processing petrochemical feedstocks to making commodity chemicals to doing transformations in pharmaceutical products. The list goes on and on.”

      “These reactions are key to making many products we use daily,” adds Roman-Leshkov, a professor of chemical engineering and chemistry.

      But the people who study redox half-reactions, also known as electrochemical reactions, are part of an entirely different research community than those studying non-redox chemical reactions, known as thermochemical reactions. As a result, even though the technique used in the new study, which involves applying a small external voltage, was well-known in the electrochemical research community, it had not been systematically applied to acid-catalyzed thermochemical reactions.

      People working on thermochemical catalysis, Surendranath says, “usually don’t consider” the role of the electrochemical potential at the catalyst surface, “and they often don’t have good ways of measuring it. And what this study tells us is that relatively small changes, on the order of a few hundred millivolts, can have huge impacts — orders of magnitude changes in the rates of catalyzed reactions at those surfaces.”

      “This overlooked parameter of surface potential is something we should pay a lot of attention to because it can have a really, really outsized effect,” he says. “It changes the paradigm of how we think about catalysis.”

      Chemists traditionally think about surface catalysis based on the chemical binding energy of molecules to active sites on the surface, which influences the amount of energy needed for the reaction, he says. But the new findings show that the electrostatic environment is “equally important in defining the rate of the reaction.”

      The team has already filed a provisional patent application on parts of the process and is working on ways to apply the findings to specific chemical processes. Westendorff says their findings suggest that “we should design and develop different types of reactors to take advantage of this sort of strategy. And we’re working right now on scaling up these systems.”

      While their experiments so far were done with a two-dimensional planar electrode, most industrial reactions are run in three-dimensional vessels filled with powders. Catalysts are distributed through those powders, providing a lot more surface area for the reactions to take place. “We’re looking at how catalysis is currently done in industry and how we can design systems that take advantage of the already existing infrastructure,” Westendorff says.

      Surendranath adds that these new findings “raise tantalizing possibilities: Is this a more general phenomenon? Does electrochemical potential play a key role in other reaction classes as well? In our mind, this reshapes how we think about designing catalysts and promoting their reactivity.”

      Roman-Leshkov adds that “traditionally people who work in thermochemical catalysis would not associate these reactions with electrochemical processes at all. However, introducing this perspective to the community will redefine how we can integrate electrochemical characteristics into thermochemical catalysis. It will have a big impact on the community in general.”

      While there has typically been little interaction between electrochemical and thermochemical catalysis researchers, Surendranath says, “this study shows the community that there’s really a blurring of the line between the two, and that there is a huge opportunity in cross-fertilization between these two communities.”

      Westerndorff adds that to make it work, “you have to design a system that’s pretty unconventional to either community to isolate this effect.” And that helps explain why such a dramatic effect had never been seen before. He notes that even their paper’s editor asked them why this effect hadn’t been reported before. The answer has to do with “how disparate those two ideologies were before this,” he says. “It’s not just that people don’t really talk to each other. There are deep methodological differences between how the two communities conduct experiments. And this work is really, we think, a great step toward bridging the two.”

      In practice, the findings could lead to far more efficient production of a wide variety of chemical materials, the team says. “You get orders of magnitude changes in rate with very little energy input,” Surendranath says. “That’s what’s amazing about it.”

      The findings, he says, “build a more holistic picture of how catalytic reactions at interfaces work, irrespective of whether you’re going to bin them into the category of electrochemical reactions or thermochemical reactions.” He adds that “it’s rare that you find something that could really revise our foundational understanding of surface catalytic reactions in general. We’re very excited.”

      “This research is of the highest quality,” says Costas Vayenas, a professor of engineering at the university of Patras, in Greece, who was not associated with the study. The work “is very promising for practical applications, particularly since it extends previous related work in redox catalytic systems,” he says.

      The team included MIT postdoc Max Hulsey PhD ’22 and graduate student Thejas Wesley PhD ’23, and was supported by the Air Force Office of Scientific Research and the U.S. Department of Energy Basic Energy Sciences. More

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      in Environment

      Susan Solomon wins VinFuture Award for Female Innovators

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      Lee and Geraldine Martin Professor of Environmental Studies Susan Solomon has been awarded the 2023 VinFuture Award for Female Innovators. Solomon was picked out of almost 1,400 international nominations across four categories for “The discovery of the ozone depletion mechanism in Antarctica, contributing to the establishment of the Montreal Protocol.” The award, which comes with a $500,000 prize, highlights outstanding female researchers and innovators that can serve as role models for aspiring scientists.

      “I’m tremendously humbled by that, and I’ll do my best to live up to it,” says Solomon, who attended the ceremony in Hanoi, Vietnam, on Dec. 20.

      The VinFuture Awards are given annually to “honor scientific research and breakthrough technological innovations that can make a significant difference” according to their site. In addition to Female Innovators, the award has two other special categories, Innovators from Developing Countries and Innovators with Outstanding Achievements in Emerging Fields, as well as their overall grand prize. The awards have been given out by the Vietnam-based VinFuture Foundation since 2021.

      “Countries all around the world are part of scientific progress and innovation, and that a developing country is honoring that is really very lovely,” says Solomon, whose career as an atmospheric chemist has brought her onto the international stage and has shown her firsthand how important developing countries are in crafting global policy.

      In 1986 Solomon led an expedition of 16 scientists to Antarctica to measure the degradation of the ozone layer; she was the only woman on the team. She and her collaborators were able to figure out the atmospheric chemistry of chlorofluorocarbons and other similar chemicals that are now known as ozone-depleting substances. This work became foundational to the creation of the Montreal Protocol, an international agreement that banned damaging chemicals and has allowed the ozone to recover.

      Solomon joined the MIT faculty in 2012 and holds joint appointments in the departments of Chemistry and Earth, Atmospheric and Planetary Sciences. The success of the Montreal Protocol demonstrates the ability for international cooperation to enact effective environmental agreements; Solomon sees it as a blueprint for crafting further policy when it comes to addressing global climate change.

      “Women can do anything, even help save the ozone layer and solve other environmental problems,” she says. “Today’s problem of climate change is for all of us to be involved in solving.” More

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      in Energy

      Cobalt-free batteries could power cars of the future

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      Many electric vehicles are powered by batteries that contain cobalt — a metal that carries high financial, environmental, and social costs.

      MIT researchers have now designed a battery material that could offer a more sustainable way to power electric cars. The new lithium-ion battery includes a cathode based on organic materials, instead of cobalt or nickel (another metal often used in lithium-ion batteries).

      In a new study, the researchers showed that this material, which could be produced at much lower cost than cobalt-containing batteries, can conduct electricity at similar rates as cobalt batteries. The new battery also has comparable storage capacity and can be charged up faster than cobalt batteries, the researchers report.

      “I think this material could have a big impact because it works really well,” says Mircea Dincă, the W.M. Keck Professor of Energy at MIT. “It is already competitive with incumbent technologies, and it can save a lot of the cost and pain and environmental issues related to mining the metals that currently go into batteries.”

      Dincă is the senior author of the study, which appears today in the journal ACS Central Science. Tianyang Chen PhD ’23 and Harish Banda, a former MIT postdoc, are the lead authors of the paper. Other authors include Jiande Wang, an MIT postdoc; Julius Oppenheim, an MIT graduate student; and Alessandro Franceschi, a research fellow at the University of Bologna.

      Alternatives to cobalt

      Most electric cars are powered by lithium-ion batteries, a type of battery that is recharged when lithium ions flow from a positively charged electrode, called a cathode, to a negatively electrode, called an anode. In most lithium-ion batteries, the cathode contains cobalt, a metal that offers high stability and energy density.

      However, cobalt has significant downsides. A scarce metal, its price can fluctuate dramatically, and much of the world’s cobalt deposits are located in politically unstable countries. Cobalt extraction creates hazardous working conditions and generates toxic waste that contaminates land, air, and water surrounding the mines.

      “Cobalt batteries can store a lot of energy, and they have all of features that people care about in terms of performance, but they have the issue of not being widely available, and the cost fluctuates broadly with commodity prices. And, as you transition to a much higher proportion of electrified vehicles in the consumer market, it’s certainly going to get more expensive,” Dincă says.

      Because of the many drawbacks to cobalt, a great deal of research has gone into trying to develop alternative battery materials. One such material is lithium-iron-phosphate (LFP), which some car manufacturers are beginning to use in electric vehicles. Although still practically useful, LFP has only about half the energy density of cobalt and nickel batteries.

      Another appealing option are organic materials, but so far most of these materials have not been able to match the conductivity, storage capacity, and lifetime of cobalt-containing batteries. Because of their low conductivity, such materials typically need to be mixed with binders such as polymers, which help them maintain a conductive network. These binders, which make up at least 50 percent of the overall material, bring down the battery’s storage capacity.

      About six years ago, Dincă’s lab began working on a project, funded by Lamborghini, to develop an organic battery that could be used to power electric cars. While working on porous materials that were partly organic and partly inorganic, Dincă and his students realized that a fully organic material they had made appeared that it might be a strong conductor.

      This material consists of many layers of TAQ (bis-tetraaminobenzoquinone), an organic small molecule that contains three fused hexagonal rings. These layers can extend outward in every direction, forming a structure similar to graphite. Within the molecules are chemical groups called quinones, which are the electron reservoirs, and amines, which help the material to form strong hydrogen bonds.

      Those hydrogen bonds make the material highly stable and also very insoluble. That insolubility is important because it prevents the material from dissolving into the battery electrolyte, as some organic battery materials do, thereby extending its lifetime.

      “One of the main methods of degradation for organic materials is that they simply dissolve into the battery electrolyte and cross over to the other side of the battery, essentially creating a short circuit. If you make the material completely insoluble, that process doesn’t happen, so we can go to over 2,000 charge cycles with minimal degradation,” Dincă says.

      Strong performance

      Tests of this material showed that its conductivity and storage capacity were comparable to that of traditional cobalt-containing batteries. Also, batteries with a TAQ cathode can be charged and discharged faster than existing batteries, which could speed up the charging rate for electric vehicles.

      To stabilize the organic material and increase its ability to adhere to the battery’s current collector, which is made of copper or aluminum, the researchers added filler materials such as cellulose and rubber. These fillers make up less than one-tenth of the overall cathode composite, so they don’t significantly reduce the battery’s storage capacity.

      These fillers also extend the lifetime of the battery cathode by preventing it from cracking when lithium ions flow into the cathode as the battery charges.

      The primary materials needed to manufacture this type of cathode are a quinone precursor and an amine precursor, which are already commercially available and produced in large quantities as commodity chemicals. The researchers estimate that the material cost of assembling these organic batteries could be about one-third to one-half the cost of cobalt batteries.

      Lamborghini has licensed the patent on the technology. Dincă’s lab plans to continue developing alternative battery materials and is exploring possible replacement of lithium with sodium or magnesium, which are cheaper and more abundant than lithium. More

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      in Energy

      Study reveals a reaction at the heart of many renewable energy technologies

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      A key chemical reaction — in which the movement of protons between the surface of an electrode and an electrolyte drives an electric current — is a critical step in many energy technologies, including fuel cells and the electrolyzers used to produce hydrogen gas.

      For the first time, MIT chemists have mapped out in detail how these proton-coupled electron transfers happen at an electrode surface. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies.

      “Our advance in this paper was studying and understanding the nature of how these electrons and protons couple at a surface site, which is relevant for catalytic reactions that are important in the context of energy conversion devices or catalytic reactions,” says Yogesh Surendranath, a professor of chemistry and chemical engineering at MIT and the senior author of the study.

      Among their findings, the researchers were able to trace exactly how changes in the pH of the electrolyte solution surrounding an electrode affect the rate of proton motion and electron flow within the electrode.

      MIT graduate student Noah Lewis is the lead author of the paper, which appears today in Nature Chemistry. Ryan Bisbey, a former MIT postdoc; Karl Westendorff, an MIT graduate student; and Alexander Soudackov, a research scientist at Yale University, are also authors of the paper.

      Passing protons

      Proton-coupled electron transfer occurs when a molecule, often water or an acid, transfers a proton to another molecule or to an electrode surface, which stimulates the proton acceptor to also take up an electron. This kind of reaction has been harnessed for many energy applications.

      “These proton-coupled electron transfer reactions are ubiquitous. They are often key steps in catalytic mechanisms, and are particularly important for energy conversion processes such as hydrogen generation or fuel cell catalysis,” Surendranath says.

      In a hydrogen-generating electrolyzer, this approach is used to remove protons from water and add electrons to the protons to form hydrogen gas. In a fuel cell, electricity is generated when protons and electrons are removed from hydrogen gas and added to oxygen to form water.

      Proton-coupled electron transfer is common in many other types of chemical reactions, for example, carbon dioxide reduction (the conversion of carbon dioxide into chemical fuels by adding electrons and protons). Scientists have learned a great deal about how these reactions occur when the proton acceptors are molecules, because they can precisely control the structure of each molecule and observe how electrons and protons pass between them. However, when proton-coupled electron transfer occurs at the surface of an electrode, the process is much more difficult to study because electrode surfaces are usually very heterogenous, with many different sites that a proton could potentially bind to.

      To overcome that obstacle, the MIT team developed a way to design electrode surfaces that gives them much more precise control over the composition of the electrode surface. Their electrodes consist of sheets of graphene with organic, ring-containing compounds attached to the surface. At the end of each of these organic molecules is a negatively charged oxygen ion that can accept protons from the surrounding solution, which causes an electron to flow from the circuit into the graphitic surface.

      “We can create an electrode that doesn’t consist of a wide diversity of sites but is a uniform array of a single type of very well-defined sites that can each bind a proton with the same affinity,” Surendranath says. “Since we have these very well-defined sites, what this allowed us to do was really unravel the kinetics of these processes.”

      Using this system, the researchers were able to measure the flow of electrical current to the electrodes, which allowed them to calculate the rate of proton transfer to the oxygen ion at the surface at equilibrium — the state when the rates of proton donation to the surface and proton transfer back to solution from the surface are equal. They found that the pH of the surrounding solution has a significant effect on this rate: The highest rates occurred at the extreme ends of the pH scale — pH 0, the most acidic, and pH 14, the most basic.

      To explain these results, researchers developed a model based on two possible reactions that can occur at the electrode. In the first, hydronium ions (H3O+), which are in high concentration in strongly acidic solutions, deliver protons to the surface oxygen ions, generating water. In the second, water delivers protons to the surface oxygen ions, generating hydroxide ions (OH-), which are in high concentration in strongly basic solutions.

      However, the rate at pH 0 is about four times faster than the rate at pH 14, in part because hydronium gives up protons at a faster rate than water.

      A reaction to reconsider

      The researchers also discovered, to their surprise, that the two reactions have equal rates not at neutral pH 7, where hydronium and hydroxide concentrations are equal, but at pH 10, where the concentration of hydroxide ions is 1 million times that of hydronium. The model suggests this is because the forward reaction involving proton donation from hydronium or water contributes more to the overall rate than the backward reaction involving proton removal by water or hydroxide.

      Existing models of how these reactions occur at electrode surfaces assume that the forward and backward reactions contribute equally to the overall rate, so the new findings suggest that those models may need to be reconsidered, the researchers say.

      “That’s the default assumption, that the forward and reverse reactions contribute equally to the reaction rate,” Surendranath says. “Our finding is really eye-opening because it means that the assumption that people are using to analyze everything from fuel cell catalysis to hydrogen evolution may be something we need to revisit.”

      The researchers are now using their experimental setup to study how adding different types of ions to the electrolyte solution surrounding the electrode may speed up or slow down the rate of proton-coupled electron flow.

      “With our system, we know that our sites are constant and not affecting each other, so we can read out what the change in the solution is doing to the reaction at the surface,” Lewis says.

      The research was funded by the U.S. Department of Energy Office of Basic Energy Sciences. More

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      in Energy

      Celebrating five years of MIT.nano

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      There is vast opportunity for nanoscale innovation to transform the world in positive ways — expressed MIT.nano Director Vladimir Bulović as he posed two questions to attendees at the start of the inaugural Nano Summit: “Where are we heading? And what is the next big thing we can develop?”

      “The answer to that puts into perspective our main purpose — and that is to change the world,” Bulović, the Fariborz Maseeh Professor of Emerging Technologies, told an audience of more than 325 in-person and 150 virtual participants gathered for an exploration of nano-related research at MIT and a celebration of MIT.nano’s fifth anniversary.

      Over a decade ago, MIT embarked on a massive project for the ultra-small — building an advanced facility to support research at the nanoscale. Construction of MIT.nano in the heart of MIT’s campus, a process compared to assembling a ship in a bottle, began in 2015, and the facility launched in October 2018.

      Fast forward five years: MIT.nano now contains nearly 170 tools and instruments serving more than 1,200 trained researchers. These individuals come from over 300 principal investigator labs, representing more than 50 MIT departments, labs, and centers. The facility also serves external users from industry, other academic institutions, and over 130 startup and multinational companies.

      A cross section of these faculty and researchers joined industry partners and MIT community members to kick off the first Nano Summit, which is expected to become an annual flagship event for MIT.nano and its industry consortium. Held on Oct. 24, the inaugural conference was co-hosted by the MIT Industrial Liaison Program.

      Six topical sessions highlighted recent developments in quantum science and engineering, materials, advanced electronics, energy, biology, and immersive data technology. The Nano Summit also featured startup ventures and an art exhibition.

      Watch the videos here.

      Seeing and manipulating at the nanoscale — and beyond

      “We need to develop new ways of building the next generation of materials,” said Frances Ross, the TDK Professor in Materials Science and Engineering (DMSE). “We need to use electron microscopy to help us understand not only what the structure is after it’s built, but how it came to be. I think the next few years in this piece of the nano realm are going to be really amazing.”

      Speakers in the session “The Next Materials Revolution,” chaired by MIT.nano co-director for Characterization.nano and associate professor in DMSE James LeBeau, highlighted areas in which cutting-edge microscopy provides insights into the behavior of functional materials at the nanoscale, from anti-ferroelectrics to thin-film photovoltaics and 2D materials. They shared images and videos collected using the instruments in MIT.nano’s characterization suites, which were specifically designed and constructed to minimize mechanical-vibrational and electro-magnetic interference.

      Later, in the “Biology and Human Health” session chaired by Boris Magasanik Professor of Biology Thomas Schwartz, biologists echoed the materials scientists, stressing the importance of the ultra-quiet, low-vibration environment in Characterization.nano to obtain high-resolution images of biological structures.

      “Why is MIT.nano important for us?” asked Schwartz. “An important element of biology is to understand the structure of biology macromolecules. We want to get to an atomic resolution of these structures. CryoEM (cryo-electron microscopy) is an excellent method for this. In order to enable the resolution revolution, we had to get these instruments to MIT. For that, MIT.nano was fantastic.”

      Seychelle Vos, the Robert A. Swanson (1969) Career Development Professor of Life Sciences, shared CryoEM images from her lab’s work, followed by biology Associate Professor Joey Davis who spoke about image processing. When asked about the next stage for CryoEM, Davis said he’s most excited about in-situ tomography, noting that there are new instruments being designed that will improve the current labor-intensive process.

      To chart the future of energy, chemistry associate professor Yogi Surendranath is also using MIT.nano to see what is happening at the nanoscale in his research to use renewable electricity to change carbon dioxide into fuel.

      “MIT.nano has played an immense role, not only in facilitating our ability to make nanostructures, but also to understand nanostructures through advanced imaging capabilities,” said Surendranath. “I see a lot of the future of MIT.nano around the question of how nanostructures evolve and change under the conditions that are relevant to their function. The tools at MIT.nano can help us sort that out.”

      Tech transfer and quantum computing

      The “Advanced Electronics” session chaired by Jesús del Alamo, the Donner Professor of Science in the Department of Electrical Engineering and Computer Science (EECS), brought together industry partners and MIT faculty for a panel discussion on the future of semiconductors and microelectronics. “Excellence in innovation is not enough, we also need to be excellent in transferring these to the marketplace,” said del Alamo. On this point, panelists spoke about strengthening the industry-university connection, as well as the importance of collaborative research environments and of access to advanced facilities, such as MIT.nano, for these environments to thrive.

      The session came on the heels of a startup exhibit in which eleven START.nano companies presented their technologies in health, energy, climate, and virtual reality, among other topics. START.nano, MIT.nano’s hard-tech accelerator, provides participants use of MIT.nano’s facilities at a discounted rate and access to MIT’s startup ecosystem. The program aims to ease hard-tech startups’ transition from the lab to the marketplace, surviving common “valleys of death” as they move from idea to prototype to scaling up.

      When asked about the state of quantum computing in the “Quantum Science and Engineering” session, physics professor Aram Harrow related his response to these startup challenges. “There are quite a few valleys to cross — there are the technical valleys, and then also the commercial valleys.” He spoke about scaling superconducting qubits and qubits made of suspended trapped ions, and the need for more scalable architectures, which we have the ingredients for, he said, but putting everything together is quite challenging.

      Throughout the session, William Oliver, professor of physics and the Henry Ellis Warren (1894) Professor of Electrical Engineering and Computer Science, asked the panelists how MIT.nano can address challenges in assembly and scalability in quantum science.

      “To harness the power of students to innovate, you really need to allow them to get their hands dirty, try new things, try all their crazy ideas, before this goes into a foundry-level process,” responded Kevin O’Brien, associate professor in EECS. “That’s what my group has been working on at MIT.nano, building these superconducting quantum processors using the state-of-the art fabrication techniques in MIT.nano.”

      Connecting the digital to the physical

      In his reflections on the semiconductor industry, Douglas Carlson, senior vice president for technology at MACOM, stressed connecting the digital world to real-world application. Later, in the “Immersive Data Technology” session, MIT.nano associate director Brian Anthony explained how, at the MIT.nano Immersion Lab, researchers are doing just that.

      “We think about and facilitate work that has the human immersed between hardware, data, and experience,” said Anthony, principal research scientist in mechanical engineering. He spoke about using the capabilities of the Immersion Lab to apply immersive technologies to different areas — health, sports, performance, manufacturing, and education, among others. Speakers in this session gave specific examples in hardware, pediatric health, and opera.

      Anthony connected this third pillar of MIT.nano to the fab and characterization facilities, highlighting how the Immersion Lab supports work conducted in other parts of the building. The Immersion Lab’s strength, he said, is taking novel work being developed inside MIT.nano and bringing it up to the human scale to think about applications and uses.

      Artworks that are scientifically inspired

      The Nano Summit closed with a reception at MIT.nano where guests could explore the facility and gaze through the cleanroom windows, where users were actively conducting research. Attendees were encouraged to visit an exhibition on MIT.nano’s first- and second-floor galleries featuring work by students from the MIT Program in Art, Culture, and Technology (ACT) who were invited to utilize MIT.nano’s tool sets and environments as inspiration for art.

      In his closing remarks, Bulović reflected on the community of people who keep MIT.nano running and who are using the tools to advance their research. “Today we are celebrating the facility and all the work that has been done over the last five years to bring it to where it is today. It is there to function not just as a space, but as an essential part of MIT’s mission in research, innovation, and education. I hope that all of us here today take away a deep appreciation and admiration for those who are leading the journey into the nano age.” More

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      in Environment

      Bringing the environment to the forefront of engineering

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      In a recent podcast interview with MIT President Sally Kornbluth, Associate Professor Desirée Plata described her childhood pastime of roaming the backyards and businesses of her grandmother’s hometown of Gray, Maine. Through her wanderings, Plata noticed a disturbing pattern.

      “I was 7 or 8 when I caught wind of all the illness,” Plata recalls. “It seemed like in every other house there was somebody who had a neurological disorder or a cancer of some sort.”

      While driving home one night with her mom, Plata made her first environmental hypothesis from the back seat. “I told my mom, ‘I think there’s something in the water or air where these people live.’”

      The conversation happened in the late 1980s. Plata was a little older when she learned her intuition was correct: The Environmental Protection Agency determined that a waste disposal facility had contaminated drinking water in the area while processing more than 1 million gallons of waste between 1965 and 1978.

      “There was a New York Times article on it, but it was sort of buried in a Sunday paper and a lot of folks up in Maine didn’t hear about it,” Plata says.

      What most struck Plata was that Gray was a tight-knit community, and the people who owned the waste disposal facility were friends with everybody. Eventually, some of the owner’s children even got sick.

      “People don’t poison their neighbors on purpose,” Plata says. “A lot of industrial contamination happens either by accident or because the engineers don’t know better. As an environmental scientist and engineer, it’s part of my job to help industrial engineers of any variety design their systems and processes such that they are thinking about what’s going into the environment from the start.”

      The insight led Plata to MIT, first as a PhD student, then as a visiting professor, and today as the newly tenured associate professor of civil and environmental engineering.

      These days Plata’s work is a bit more complex than her early backseat musings. In fact, her efforts extend far beyond research and include mentoring students, entrepreneurship, coalition-building, and coordination across industry, academia, and government. But the work can still be traced back to the childhood insight that environmental optimization needs to be a more tangible and important part of everyone’s thinking.

      “People think sustainability is this nebulous thing they can’t get their hands around,” Plata says. “But there are actually a set of rigorous principles you can use, and each one of those has a metric or a thing you can measure to go with it. MIT is such an innovative place. If we can incorporate environmental objectives into design at a place like MIT, the hope is the world can engage as well.”

      Taking the plunge

      Plata was first introduced to environmental research in high school, but it wasn’t until she attended Union College and got to work in a research lab that she knew it was what she’d do for the rest of her life.

      After graduating from Union, Plata decided to skip a master’s degree and “take the plunge” into the MIT-Woods Hole Oceanographic Institution (WHOI) joint doctoral program.

      “Talk about drinking from a firehose,” Plata says. “Everybody you bump into knows something that can help you solve the very hard problem you’re working on.”

      Plata began the program studying oil spills, and a paper she co-authored helped spur a law that changed the way oil is transported off the coast of Massachusetts. But developments in her personal life made her want to prevent environmental disasters before they happen.

      In her last year at Union, Plata’s aunt was diagnosed with breast cancer — a disease that’s been linked to one of the chemicals dumped in Gray, Maine. While Plata was at MIT, her aunt was receiving treatment at Massachusetts General Hospital down the road, so Plata would work at the lab at night, stay with her aunt during treatments all day, and go home with her on the weekends.

      “As I’m sampling oil, I’m recognizing that nothing I’m doing is going to help women like her escape the illness,” Plata recalls.

      In her third year of the MIT-WHOI program, Plata shifted her research to explore how industrial emissions generated during the creation of materials known as carbon nanotubes could inform how those valuable new materials were forming. The work led to a dramatically more sustainable way to make the materials, which are needed for important environmental applications themselves.

      After earning her PhD, Plata served as a visiting professor at MIT for two years before working in faculty positions at Duke University and Yale University, where she studied green chemistry and green optimization. She returned to MIT as an assistant professor in civil and environmental engineering in 2018.

      Working beyond academia

      While at Yale, Plata started a company, Nth Cycle, which uses electric currents to extract critical minerals like cobalt and nickel from lithium-ion batteries and other electronic waste. The company began commercial production last year.

      Plata also works extensively with government and industry, serving on a Massachusetts committee that published a roadmap to decarbonizing the state by 2050 and advising companies both formally and informally. (She estimates she gets a call every two weeks from a new company working on a sustainability problem.)

      “It’s undeniable that industry has an enormous impact on the environment,” Plata says. “Some like to think the government can wave a magic wand and make some regulation and we won’t be in this situation, but that’s not the case. There are technical challenges that need to be solved and businesses play an incredibly important role as agents of change.”

      Plata’s research at MIT, meanwhile, is focused increasingly on methane. Last year she helped create the MIT Methane Network, which she directs.

      Plata’s research has explored ways to convert methane into less harmful carbon dioxide and other fuels in places like dairy farms and coal plants. This past summer she took a team of students to dairy barns to conduct field tests.

      “If you could take methane from coal mining out of the air globally, it’s equivalent to taking all of the combustion engine vehicles off the road, even accounting for the small generation of CO2 that we have [as the result of our process],” Plata says. “If you can fix the problem at dairy farms, it’s like all the combustion engine vehicle emissions times three. It’s a hugely impactful number.”

      Taking action

      When Plata was in fourth grade, her teacher had students pick up trash around a nearby bay. She’s since done the exercise with other fourth graders.

      “You ask them what they think they’ll find, and they say, ‘Nothing. I didn’t see any trash on the way to school today,’ but when you ask them to look, everybody fills their bag by the end of the trip, and you start to realize how much fugitive emissions of waste exists, and then you start to start thinking about all of the chemical contamination that you can’t see,” Plata says.

      One of Plata’s chief research goals can be summed up with that exercise: getting people to appreciate the importance of environmental criteria and motivating them to take action.

      “Today, I see people looking for these silver bullet solutions to solve environmental problems,” Plata says. “That’s not how we got into this mess, and it’s not how we’re going to get out of it. The problem is really distributed, so what we really need is the sum of a lot of small actions to change the system.” More

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      in Energy

      Study suggests energy-efficient route to capturing and converting CO2

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      In the race to draw down greenhouse gas emissions around the world, scientists at MIT are looking to carbon-capture technologies to decarbonize the most stubborn industrial emitters.

      Steel, cement, and chemical manufacturing are especially difficult industries to decarbonize, as carbon and fossil fuels are inherent ingredients in their production. Technologies that can capture carbon emissions and convert them into forms that feed back into the production process could help to reduce the overall emissions from these “hard-to-abate” sectors.

      But thus far, experimental technologies that capture and convert carbon dioxide do so as two separate processes, that themselves require a huge amount of energy to run. The MIT team is looking to combine the two processes into one integrated and far more energy-efficient system that could potentially run on renewable energy to both capture and convert carbon dioxide from concentrated, industrial sources.

      In a study appearing today in ACS Catalysis, the researchers reveal the hidden functioning of how carbon dioxide can be both captured and converted through a single electrochemical process. The process involves using an electrode to attract carbon dioxide released from a sorbent, and to convert it into a reduced, reusable form.

      Others have reported similar demonstrations, but the mechanisms driving the electrochemical reaction have remained unclear. The MIT team carried out extensive experiments to determine that driver, and found that, in the end, it came down to the partial pressure of carbon dioxide. In other words, the more pure carbon dioxide that makes contact with the electrode, the more efficiently the electrode can capture and convert the molecule.

      Knowledge of this main driver, or “active species,” can help scientists tune and optimize similar electrochemical systems to efficiently capture and convert carbon dioxide in an integrated process.

      The study’s results imply that, while these electrochemical systems would probably not work for very dilute environments (for instance, to capture and convert carbon emissions directly from the air), they would be well-suited to the highly concentrated emissions generated by industrial processes, particularly those that have no obvious renewable alternative.

      “We can and should switch to renewables for electricity production. But deeply decarbonizing industries like cement or steel production is challenging and will take a longer time,” says study author Betar Gallant, the Class of 1922 Career Development Associate Professor at MIT. “Even if we get rid of all our power plants, we need some solutions to deal with the emissions from other industries in the shorter term, before we can fully decarbonize them. That’s where we see a sweet spot, where something like this system could fit.”

      The study’s MIT co-authors are lead author and postdoc Graham Leverick and graduate student Elizabeth Bernhardt, along with Aisyah Illyani Ismail, Jun Hui Law, Arif Arifutzzaman, and Mohamed Kheireddine Aroua of Sunway University in Malaysia.

      Breaking bonds

      Carbon-capture technologies are designed to capture emissions, or “flue gas,” from the smokestacks of power plants and manufacturing facilities. This is done primarily using large retrofits to funnel emissions into chambers filled with a “capture” solution — a mix of amines, or ammonia-based compounds, that chemically bind with carbon dioxide, producing a stable form that can be separated out from the rest of the flue gas.

      High temperatures are then applied, typically in the form of fossil-fuel-generated steam, to release the captured carbon dioxide from its amine bond. In its pure form, the gas can then be pumped into storage tanks or underground, mineralized, or further converted into chemicals or fuels.

      “Carbon capture is a mature technology, in that the chemistry has been known for about 100 years, but it requires really large installations, and is quite expensive and energy-intensive to run,” Gallant notes. “What we want are technologies that are more modular and flexible and can be adapted to more diverse sources of carbon dioxide. Electrochemical systems can help to address that.”

      Her group at MIT is developing an electrochemical system that both recovers the captured carbon dioxide and converts it into a reduced, usable product. Such an integrated system, rather than a decoupled one, she says, could be entirely powered with renewable electricity rather than fossil-fuel-derived steam.

      Their concept centers on an electrode that would fit into existing chambers of carbon-capture solutions. When a voltage is applied to the electrode, electrons flow onto the reactive form of carbon dioxide and convert it to a product using protons supplied from water. This makes the sorbent available to bind more carbon dioxide, rather than using steam to do the same.

      Gallant previously demonstrated this electrochemical process could work to capture and convert carbon dioxide into a solid carbonate form.

      “We showed that this electrochemical process was feasible in very early concepts,” she says. “Since then, there have been other studies focused on using this process to attempt to produce useful chemicals and fuels. But there’s been inconsistent explanations of how these reactions work, under the hood.”

      Solo CO2

      In the new study, the MIT team took a magnifying glass under the hood to tease out the specific reactions driving the electrochemical process. In the lab, they generated amine solutions that resemble the industrial capture solutions used to extract carbon dioxide from flue gas. They methodically altered various properties of each solution, such as the pH, concentration, and type of amine, then ran each solution past an electrode made from silver — a metal that is widely used in electrolysis studies and known to efficiently convert carbon dioxide to carbon monoxide. They then measured the concentration of carbon monoxide that was converted at the end of the reaction, and compared this number against that of every other solution they tested, to see which parameter had the most influence on how much carbon monoxide was produced.

      In the end, they found that what mattered most was not the type of amine used to initially capture carbon dioxide, as many have suspected. Instead, it was the concentration of solo, free-floating carbon dioxide molecules, which avoided bonding with amines but were nevertheless present in the solution. This “solo-CO2” determined the concentration of carbon monoxide that was ultimately produced.

      “We found that it’s easier to react this ‘solo’ CO2, as compared to CO2 that has been captured by the amine,” Leverick offers. “This tells future researchers that this process could be feasible for industrial streams, where high concentrations of carbon dioxide could efficiently be captured and converted into useful chemicals and fuels.”

      “This is not a removal technology, and it’s important to state that,” Gallant stresses. “The value that it does bring is that it allows us to recycle carbon dioxide some number of times while sustaining existing industrial processes, for fewer associated emissions. Ultimately, my dream is that electrochemical systems can be used to facilitate mineralization, and permanent storage of CO2 — a true removal technology. That’s a longer-term vision. And a lot of the science we’re starting to understand is a first step toward designing those processes.”

      This research is supported by Sunway University in Malaysia. More

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      in Energy

      Chemists discover why photosynthetic light-harvesting is so efficient

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      When photosynthetic cells absorb light from the sun, packets of energy called photons leap between a series of light-harvesting proteins until they reach the photosynthetic reaction center. There, cells convert the energy into electrons, which eventually power the production of sugar molecules.

      This transfer of energy through the light-harvesting complex occurs with extremely high efficiency: Nearly every photon of light absorbed generates an electron, a phenomenon known as near-unity quantum efficiency.

      A new study from MIT chemists offers a potential explanation for how proteins of the light-harvesting complex, also called the antenna, achieve that high efficiency. For the first time, the researchers were able to measure the energy transfer between light-harvesting proteins, allowing them to discover that the disorganized arrangement of these proteins boosts the efficiency of the energy transduction.

      “In order for that antenna to work, you need long-distance energy transduction. Our key finding is that the disordered organization of the light-harvesting proteins enhances the efficiency of that long-distance energy transduction,” says Gabriela Schlau-Cohen, an associate professor of chemistry at MIT and the senior author of the new study.

      MIT postdocs Dihao Wang and Dvir Harris and former MIT graduate student Olivia Fiebig PhD ’22 are the lead authors of the paper, which appears this week in the Proceedings of the National Academy of Sciences. Jianshu Cao, an MIT professor of chemistry, is also an author of the paper.

      Energy capture

      For this study, the MIT team focused on purple bacteria, which are often found in oxygen-poor aquatic environments and are commonly used as a model for studies of photosynthetic light-harvesting.

      Within these cells, captured photons travel through light-harvesting complexes consisting of proteins and light-absorbing pigments such as chlorophyll. Using ultrafast spectroscopy, a technique that uses extremely short laser pulses to study events that happen on timescales of femtoseconds to nanoseconds, scientists have been able to study how energy moves within a single one of these proteins. However, studying how energy travels between these proteins has proven much more challenging because it requires positioning multiple proteins in a controlled way.

      To create an experimental setup where they could measure how energy travels between two proteins, the MIT team designed synthetic nanoscale membranes with a composition similar to those of naturally occurring cell membranes. By controlling the size of these membranes, known as nanodiscs, they were able to control the distance between two proteins embedded within the discs.

      For this study, the researchers embedded two versions of the primary light-harvesting protein found in purple bacteria, known as LH2 and LH3, into their nanodiscs. LH2 is the protein that is present during normal light conditions, and LH3 is a variant that is usually expressed only during low light conditions.

      Using the cryo-electron microscope at the MIT.nano facility, the researchers could image their membrane-embedded proteins and show that they were positioned at distances similar to those seen in the native membrane. They were also able to measure the distances between the light-harvesting proteins, which were on the scale of 2.5 to 3 nanometers.

      Disordered is better

      Because LH2 and LH3 absorb slightly different wavelengths of light, it is possible to use ultrafast spectroscopy to observe the energy transfer between them. For proteins spaced closely together, the researchers found that it takes about 6 picoseconds for a photon of energy to travel between them. For proteins farther apart, the transfer takes up to 15 picoseconds.

      Faster travel translates to more efficient energy transfer, because the longer the journey takes, the more energy is lost during the transfer.

      “When a photon gets absorbed, you only have so long before that energy gets lost through unwanted processes such as nonradiative decay, so the faster it can get converted, the more efficient it will be,” Schlau-Cohen says.

      The researchers also found that proteins arranged in a lattice structure showed less efficient energy transfer than proteins that were arranged in randomly organized structures, as they usually are in living cells.

      “Ordered organization is actually less efficient than the disordered organization of biology, which we think is really interesting because biology tends to be disordered. This finding tells us that that may not just be an inevitable downside of biology, but organisms may have evolved to take advantage of it,” Schlau-Cohen says.

      Now that they have established the ability to measure inter-protein energy transfer, the researchers plan to explore energy transfer between other proteins, such as the transfer between proteins of the antenna to proteins of the reaction center. They also plan to study energy transfer between antenna proteins found in organisms other than purple bacteria, such as green plants.

      The research was funded primarily by the U.S. Department of Energy. More