Publication Highlight

RASEI Fellows Collaboration in CHOISE Twists Halide Perovskites From a Distance

Daniel Morton — Fri, 25 Oct 2024 22:31:11 +0000

RASEI Fellows Collaboration in CHOISE Twists Halide Perovskites From a Distance Daniel Morton Fri, 10/25/2024 - 16:31

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Discovery could lead to longer-lasting EV batteries, hasten energy transition

Anonymous — Thu, 12 Sep 2024 06:00:00 +0000

Discovery could lead to longer-lasting EV batteries, hasten energy transition Anonymous (not verified) Thu, 09/12/2024 - 00:00

Mike Toney explores how lithium-ion batteries self-discharge to improve future designs

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Probing intermediate configurations of oxygen evolution catalysis across the light spectrum

Anonymous — Mon, 09 Sep 2024 06:00:00 +0000

Probing intermediate configurations of oxygen evolution catalysis across the light spectrum Anonymous (not verified) Mon, 09/09/2024 - 00:00

Mapping a route for more efficient production of sustainable fuels

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Find out more about CEDARS

This perspective article, led by RASEI Fellow Tanja Cuk, brings together researchers at six research institutions from across the United States, to describe how advances in spectroscopy and theory can map out the elementary details of the oxygen evolution reaction, a critical reaction to enable the production of fuels from sustainable energy sources.

The oxygen evolution reaction (or OER for short), is a critical step in the creation of sustainable, decarbonized fuels, such as hydrogen. Water (H₂O) can be split into hydrogen (H₂) and oxygen (O₂) using electricity. This process pulls apart strong chemical bonds – it takes a lot of energy! If we can better understand this process, we can make it more efficient, which will enable us to create clean fuels and store renewable energy, like solar and wind power, to smooth out variations in the supply. Specifically, the OER is the half-reaction that occurs at the anode (positive electrode) during electrolysis, in which the water molecules are oxidized to produce oxygen gas (O₂), protons (H⁺), and electrons. Though this sounds straightforward, the process involves multiple intermediates, or steps, many of which are currently poorly defined. Understanding this complex process requires a collaborative approach. Jin Suntivich (Cornell University) and Dhananjay Kumar (North Carolina A&T) bring expertise in making advanced materials and electrochemistry, Geoffroy Hautier (Dartmouth College) and Ismaila Dabo (Carnegie Mellon University) develop theoretical models, and Ethan Crumlin (Lawrence Berkeley National Laboratory), Tanja Cuk (CU �鶹ӰԺ), and Jin Suntivich use X-ray and optical spectroscopy to visualize the small molecular intermediates.

Imagine that you have to drive from Denver, Colorado, to Greensboro, North Carolina. If someone gave you a map that only showed your starting location and destination, it would be quite difficult. You would know that you had to head east, but you wouldn’t know what roads to take, which were the fastest moving, or where any good stops were along the way. You could probably get there, but you would get lost a few times on the way, use some of the slow roads, and maybe be stuck staying in places you didn’t want to. It would be a very inefficient journey. Now compare this to using a modern navigation app, one that has details of every road along the way, the speed limits, the traffic levels, where all the gas stations are, the good restaurants and coffee shops, and good places to stop for the night. You would be far more efficient (and happy) using the navigation app.

It is the same with a chemical reaction. If you understand the elementary steps of a reaction, you can design a system that is more efficient and effective at getting to the final product. Creating this ‘map’ for the OER is a central mission of the Center for Electrochemical Dynamics and Reactions on Surfaces (CEDARS). CEDARS is a Department of Energy funded Energy Frontier Research Center (EFRC), that brings together twelve research groups at five universities and two DOE national labs across the chemical, materials, and computational sciences. CEDARS is headed by Director Dhananjay Kumar at North Carolina A&T, with a strong program in thin materials research. This is the first EFRC awarded to an HBCU as a lead institution in the country. There are several challenges that need to be overcome before the OER process can be scaled up. Currently OER is expensive, energy intensive and not reliable for continuous long-term operation. OER requires large inputs of electricity, the catalysts used in the reaction are based on scarce materials that are unstable under long-term exposure to the harsh conditions present in the OER process. By better understanding the elementary steps of the OER reaction researchers can design cheaper, more efficient processes.

RASEI Fellow, and Associate Director of CEDARS Tanja Cuk explains that there have been a series of proposed oxygen-related intermediates (e.g. OH*, O*, O-O), but it has been hard to capture experimental evidence for them and the elementary steps that create them. “The article is a perspective on how to get at the intermediates and their dynamics within the buried electrode-electrolyte interface. The approach involves model crystalline materials, targeted spectroscopies to isolate the intermediates, and theoretical investigations that predict how they appear in the electrochemistry and the spectroscopy. We also use materials that bind the intermediates at different strengths, so that they appear statically and transiently.” This fundamental and basic energy sciences approach combines expertise from across CEDARS bringing together computational theoretical modeling, materials synthesis, and spectroscopy. The diversity of institutions involved has already provided for many student and postdoctoral exchanges that further deepen the background of the team and broaden the scope of the research. Just last month the Center Director and his graduate student visited NREL and CU to test the samples made at NCAT.

Precise control of the materials under investigation is required for effective characterization and theoretical modeling. Dhananjay Kumar, Jin Suntivich, and collaborators within CEDARS use a process called epitaxial layer deposition, a procedure where a thin crystalline layer is grown on top of a substrate. For these investigations the epitaxial layers are the OER catalysts made from ruthenium and titanium oxides that are then tested electrochemically. Geoffroy Hautier is a materials theorist who uses computational models to calculate the structure and defects that intermediates create in the materials and their impacts on x-ray and optical spectra. Ismaila Dabo takes these configurations and creates a model of the electrical and water environment around the electrode interface, describing a more realistic environment for the OER processes. To provide a more detailed understanding, the theoretical models are tested and refined based on feedback from advanced spectroscopic observations. The spectroscopies highlight static spectra of intermediate coverages and transient intermediates during OER. Jin Suntivich brings expertise in combining in-situ electrochemistry with non-linear optical techniques; Ethan Crumlin develops in-situ and time-resolved x-ray spectroscopies; Tanja Cuk combines in-situ electrochemistry with ultrafast optical spectroscopy. Integrating the computational advances with the experimental observations provides a powerful toolkit. Accurate interpretation of the spectral observations relies on the findings from the computational techniques.

While the ‘map’ for the OER has not been solved, this interdisciplinary and fundamental approach to interrogating the OER process is providing invaluable insights into how different catalysts bind to the intermediates and how this impacts different reaction pathways. By characterizing the nature of the intermediates bound to the catalyst an understanding of their equilibrium behavior during the OER process can be developed. The CEDARS team are already thinking about next steps for this powerful approach. These include understanding the non-equilibrium dynamics of these intermediates by fully time resolved x-ray and optical probes and investigating more complex material structures. The observations from these ‘in-process’ reactions will help define the roadmap to a more efficient and cost-effective approach to generate clean fuels from renewable energy sources.

NATURE ENERGY, 2024 | https://doi.org/10.1038/s41560-024-01583-x

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Stronger Together: Coupling Excitons to Polaritons for Better Solar Cells and Higher Intensity LEDs

Anonymous — Tue, 06 Aug 2024 06:00:00 +0000

Stronger Together: Coupling Excitons to Polaritons for Better Solar Cells and Higher Intensity LEDs Anonymous (not verified) Tue, 08/06/2024 - 00:00

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Highlighting Opportunities for Manufacturing Perovskite Solar Panels with a Long-Term Outlook

Anonymous — Tue, 23 Jul 2024 06:00:00 +0000

Highlighting Opportunities for Manufacturing Perovskite Solar Panels with a Long-Term Outlook Anonymous (not verified) Tue, 07/23/2024 - 00:00

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Converting captured carbon to fuel: Study assesses what’s practical and what’s not

Anonymous — Mon, 22 Jul 2024 06:00:00 +0000

Converting captured carbon to fuel: Study assesses what’s practical and what’s not Anonymous (not verified) Mon, 07/22/2024 - 00:00

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How much energy can offshore wind farms in the US produce? New study sheds light

Anonymous — Thu, 25 Apr 2024 23:43:55 +0000

How much energy can offshore wind farms in the US produce? New study sheds light Anonymous (not verified) Thu, 04/25/2024 - 17:43

RASEI Fellow Julie Lundquist highlights the importance of using simulation tools to determine the locations of installing wind turbines

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Bacterial Disco Lights: Using light to control the movement and arrangement of cyanobacteria to form liquid crystalline active matter

Anonymous — Tue, 02 Apr 2024 06:00:00 +0000

Bacterial Disco Lights: Using light to control the movement and arrangement of cyanobacteria to form liquid crystalline active matter Anonymous (not verified) Tue, 04/02/2024 - 00:00

Daniel Morton

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This collaboration, between a bacterial biochemist and a condensed-matter physicist, use light to control the movement and arrangement of cyanobacteria, forming two- and three-dimensional nematic liquid crystalline states that could provide significant opportunities to regulate the behavior of the bacterial systems and open up new areas in bio-manufacturing that use carbon dioxide as the feedstock for the production of oxygen, biofuels, or biomaterials.

Cyanobacteria are one of the most ancient forms of life, dating back to ~3.5 billion years ago. Highly abundant, these bacterial dinosaurs use carbon dioxide and light as inputs and convert them to energy, motion, and oxygen. The term ‘Active Matter’ is used to describe systems that take in and dissipate energy at the level of constituent particles and, in the process, perform systematic movements. Essentially all forms of life can be considered active matter. Injecting energy into an active matter system often leads to emergent collective phenomena, think flocks of birds or schools of fish. Though there has been extensive research on the photosynthetic action of cyanobacteria, quantitative exploration of the motion, arrangement, and potential collective behavior of cyanobacteria is relatively unexplored. Intrigued by exploring these phenomena further, two RASEI Fellows formed an unusual partnership to investigate.

In 2018 RASEI Fellows Jeff Cameron and Ivan Smalyukh were awarded a grant from the DOE to build a specialized microscope system for imaging photosynthetic microbes. The system includes an ultrafast laser system that enable multi-photon excitation in the pigments in the cyanobacterial cells, a technique that was essential for this investigation. Cameron, a member of the Department of Biochemistry, is an expert in cyanobacteria and photosynthesis, while Smalyukh, a member of the Department of Physics, is an expert in condensed matter physics, with a specialty in liquid crystals. The unusual nature of this partnership is not lost on them. “Normally Biochemistry and Physics are separated, making close collaboration difficult” explains Cameron, “especially when close experimental collaboration is needed, requiring routine access to environmental chambers and biological research labs as well as advanced laser labs”. A key feature in how RASEI is setup is the co-location of multidisciplinary researchers. Cameron notes “This enables researchers to work hand-in-hand on studies that would simply not be possible if the two labs were on opposite sides of campus”.

Working together the findings from this team were conclusive; the cyanobacteria danced to the light! When a localized light was introduced to the bacteria, they harvested energy from the light through photosynthesis and used the energy generated to move towards the light. Experiments were done in two modes, one where the bacteria were confined to a two-dimensional plane, and the second where they could move in three-dimensions. In the two-dimensional system as the density of bacteria in the colony increased in the illuminated area emergent collective behavior emerged, with the bacteria forming a nematic arrangement, similar to that observed in synthetic liquid crystals. This emergent behavior was found to develop dramatically over time, with the direction, orientation, and trajectory of the cyanobacteria all changing, thought to be driven by an optimization toward enhanced light energy intake. Expanding this to the three-dimensional studies the team found that the cyanobacteria stacked on top of each other to form 3D active nematic slabs. The specialized microscope system enabled the teams to effectively explore these three-dimensional structures, even looking at cross-sectional views of the emergent behaviors. Comprehensive studies explored a range of properties of these emergent ‘Flocks of Cyanobacteria’, including examining transitions between fluid and gel states, the impacts of introducing defects, interactions between polydomain systems, and movement around foreign objects.

Precise control of biological systems is the ‘holy grail’ in biomanufacturing. Spatial patterning of the cyanobacteria impacts the structural and functional properties of the bacteria. Cyanobacteria only require carbon dioxide, water, and light, and can produce biofuels, commodity chemicals, and minerals, all while pulling carbon dioxide out of the air and producing oxygen. Understanding, and more importantly being able to reliably control, the optimal conditions for these bio-manufacturing to operate has the potential to enable new avenues to utilize these biological systems in benefiting society and the environment.

Armed with an enhanced understanding of how these bacteria move and can be controlled by light, the team is excited by the possibilities. Smalyukh explains “Our discovery of out-of-equilibrium active matter phase transitions in filamentous cyanobacteria systems may find utility in commanding collective behavior of cyanobacteria, with potential biotechnological utility ranging from control of bacterial mats and blooms, to oxygen generation an inhibition of toxin production”. Cameron adds “the possibilities are endless-once we can control the growth and orientation of biology, we can create novel materials and start to think about entirely new, environmentally-friendly, biomanufacturing opportunities.”

There is something poignant when you consider employing these ancient lifeforms, that were responsible for the Great Oxidation Event, profoundly changing life as we know it, as active agents in pulling carbon dioxide, the key causative greenhouse gas in the climate crisis, out of our atmosphere. The understanding and control made possible through the investigations described here bring this one step closer.

NATURE COMMUNICATIONS MATERIALS, 2024, 5, 37

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Analyses of the Opportunities and Barriers associated with Electrochemical-Driven Decarbonization

Anonymous — Fri, 27 Oct 2023 06:00:00 +0000

Analyses of the Opportunities and Barriers associated with Electrochemical-Driven Decarbonization Anonymous (not verified) Fri, 10/27/2023 - 00:00

Daniel Morton

The Climate Crisis has already caused increases in the occurrence of major weather events, such as heat waves, wildfires, and sea level rise worldwide. With less than three months left, 2023 is on track to be the hottest year in a 174-year record.

A Review on previous analysis methods for electrochemical reduction of carbon dioxide

Decarbonization of the chemical industry through electrification

Barriers and opportunities for the deployment of carbon dioxide electrolysis in net-zero emissions energy systems

Analysis of the use of electrochemical carbon dioxide reduction for air-to-syngas pathways

The emission of carbon into the Earth’s atmosphere is driving this change and in 2022 CO₂ emissions reached an all-time-high of more than 36.8 Gt-CO₂. That is the equivalent of 368,000 fully loaded U.S. aircraft carriers, or put another way, 1 Gt is roughly twice the mass of all humans on the planet. In 2022 the world is further away from net-zero emissions than we have ever been before.

In order to effectively address the climate crisis, we cannot rely solely on a transition to clean and renewable energy sources and reduction of carbon emissions, we are going to need effective methods to remove the carbon we have already put into the atmosphere to mitigate the increasing frequency of extreme weather events. The technologies need to achieve this are still emerging, and there are many aspects that are not fully understood. Two RASEI Fellows, Bri-Mathias Hodge and Wilson Smith have, over the past two years, been part of a series of studies that have applied rigorous analysis and modeling approaches to provide a thorough assessment of decarbonization and carbon capture technologies that outline the barriers, and opportunities, of a circular economy for carbon.

These studies have explored a series of different perspectives on how electrification and the electrochemical reduction of carbon dioxide can impact different sectors in our efforts to accelerate decarbonization. The scope of these studies has been broad, exploring impacts on the transport sector, chemical (this study also brought in RASEI Fellow Kyri Baker as a collaborator), and industrial complexes. This includes everything from more efficient and direct methods for heating, to replacing the carbon building blocks we pull out of the ground in the form of oil and gas with ones we can pull out of the atmosphere.

The most recent article in this series, which was published this month in the Journal Energy & Environmental Sciences, revolves around the use of direct air carbon dioxide capture (DACC), powered by renewable electricity, to generate syngas, an essential industrial feedstock for the production of fuels, plastics, advanced materials, and medicines. The electrochemical carbon dioxide reduction approach offers a more energy efficient strategy that can produce this valuable commodity while reducing the amount of carbon in our atmosphere.

RASEI Fellows Bri-Mathias Hodge and Wilson Smith has been part of a series of collaborative studies that have explored the use of electrochemical carbon reduction.

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The future of recycling could one day mean dissolving plastic with electricity

Anonymous — Mon, 03 Jul 2023 06:00:00 +0000

The future of recycling could one day mean dissolving plastic with electricity Anonymous (not verified) Mon, 07/03/2023 - 00:00

Daniel Morton

Plastics have proven to be a revolutionary class of materials, that are durable, lightweight, water resistant and relatively inexpensive and easy to manufacture. It is hard to think of a modern piece of technology that doesn’t include some plastic components, from electronics to plastic bottles.

The same properties that make plastics useful are also behind the creation of a global waste crisis.

Research Article

CU �鶹ӰԺ Today Highlight

Media Highlights:

Energy & Environment Leader

Materials Today

Plastics are polymers, long chains of molecules connecting together repeating links called monomers. By changing the chemical structure of the monomers, and the way in which they are connected together, the properties of the plastic can be engineered.

The majority of plastics are durable, which is great for an application (no one wants a leaky bottle of water), but not so great when you need to dispose of the application. Waste plastics can litter the environment for centuries. Larger pieces of plastic, such as bags, straws, bottles, packaging and many everyday objects, are called macroplastics. When present in the environment these pose a threat to wildlife through entanglement or consumption. The problem doesn’t stop there. Macroplastics can break down into smaller and smaller pieces, forming microplastics (<5 mm long), that are becoming increasingly ubiquitous, now found as pollutants in every part of our environment. While these plastics are being broken down into smaller pieces, on the chemical level the strong polymer chains remain strong, making them very hard to get rid of. It is estimated that on our current trajectory, by 2050 there could be more plastic in the ocean than fish (by weight; Ellen MacArthur Foundation, 2016).

Due to a combination of the strength of plastics and poor waste management systems, it is estimated that only 15 % of plastic waste is recycled. Most of the population operates on a linear economy model, a so-called “take-make-discard”, where raw materials are refined, used to manufacture products, which are then simply disposed of at the end of life. It is imperative that we move to a circular economy model for plastic use and recycling, and this work, by two teams of RASEI researchers, provides a step toward this transition.

Current plastic recycling methods are not up to the task. The most globally used method is called mechanical recycling. Plastics, which have been collected and separated, are mechanically broken down through a combination of chopping and grinding to produce a powder that is then melted and extruded into pellets ready for reheating and remolding. This process can only be done a few times. Melting can be destructive to the chemical structure and eventually, through repeated cycles, the plastic loses its strength.

RASEI Fellow Oana Luca and her team, in collaboration with the group of RASEI Fellow Seth Marder, have demonstrated an electrochemical approach to chemical recycling of polyethylene terephthalate (PET) plastics. PET is one of the most common plastics, used in clothing, food containers and bottles. In chemical recycling the work is done at the molecular level. By applying an electric current to a solution of the plastic and a redox catalyst (a molecule capable of capturing and then donating an electron), the polymer chain is broken in a selective manner to produce the original starting materials. Instead of getting a random mixture of chemical structures, as you would through heating in mechanical recycling, you get clean starting materials, which, after separation, can be used to produce new plastics. Using this technique there is no limit to the number of times plastics could be recycled. With the amount of plastic waste in the world, you would never have to use new starting materials!

While this approach holds great promise, there is a lot of work still to be done. The process shown in the lab could break down about 40 milligrams (about 1 /500 of a 16 Oz PET bottle), over a period of several hours.

“Although this is a great start, we believe that lots of work needs to be done to optimize the process as well as scale it up so it can eventually be applied on an industrial scale” said Phuc Pham, a doctoral student in the Luca Group.

The generality of this electrochemical approach offers an exciting opportunity. Different types of plastics could be put into the same chemical reactor and broken down into their respective starting materials, which could then be separated, which could significantly mitigate and streamline some of the waste collection and management issues.

“There are so many polymers and materials out there that people aren’t recycling at all. They’re not being collected. This is the beginning of many, many different kinds of chemistries” said Oana Luca.

This collaborative team, led by RASEI Fellow Oana Luca and including RASEI Director Seth Marder describes new approaches to PET recycling.

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