Chemical manufacturers frequently use toxic solvents such as alcohols and benzene to make products like pharmaceuticals and plastics. Researchers are examining a previously overlooked and misunderstood phenomenon in the chemical reactions used to make these products. This discovery brings a new fundamental understanding of catalytic chemistry and a steppingstone to practical applications that could someday make chemical manufacturing less wasteful and more environmentally sound.
The study led by University of Illinois Urbana-Champaign researcher David Flaherty, University of Minnesota, Twin Cities researcher Matthew Neurock and Virginia Tech researcher Ayman Karim is published in the journal Science.
Combining solvents and metal nanoparticles accelerates many chemical reactions and helps maximize yield and profit margins for the chemical industry. However, many solvents are toxic and difficult to safely dispose, the researchers said. Water works, too, but it is not nearly as efficient or reliable as organic solvents. The reason for the difference was thought to be the limited solubility of some reactants in water. However, multiple irregularities in experimental data have led the team to realize the reasons for these differences were not fully understood.
To better understand the process, the team ran experiments to analyze the reduction of oxygen to hydrogen peroxide – one set using water, another with methanol, and others with water and methanol mixtures. All experiments used palladium nanoparticles.
“In experiments with methanol, we observed spontaneous decomposition of the solvent that leaves an organic residue, or scum, on the surface of the nanoparticles,” said Flaherty, a professor of chemical and biomolecular engineering at Illinois. “In some cases, the scumlike residue clings to the nanoparticles and increases reaction rates and the amount of hydrogen peroxide formed instead of hampering the reaction. This observation made us wonder how it could be helping.”
The team found that the residue, or surface redox mediator, oxygen-containing species, including a key component hydroxymethyl. It accumulates on the palladium nanoparticles’ surface and opens new chemical reaction pathways, the study reports.
“Once formed, the residue becomes part of the catalytic cycle and is likely responsible for some of the different efficiencies among solvents reported over the past 40 years of work on this reaction,” Flaherty said. “Our work provides strong evidence that these surface redox mediators form in alcohol solvents and that they may explain many past mysteries for this chemistry.”
By working with multiple types of experiments and computational simulations, the team learned that these redox mediators effectively transfer both protons and electrons to reactants, whereas reactions in pure water transfer protons easily, but not electrons. These mediators also alter the nanoparticles’ surface in a way that lowers the energy barrier to be overcome for proton and electron transfer, the study reports.
“We show that the alcohol solvents as well as organic additives can react to form metal-bound surface mediators that act much in the same way that the enzymatic cofactors in our bodies do in catalyzing oxidation and reduction reactions,” Neurock said.
Additionally, this work may have implications for reducing the amounts of solvent used and waste generated in the chemical industry.
“Our research suggests that for some situations, chemical producers could form the surface redox mediators by adding small amounts of an additive to pure water instead of pumping thousands of gallons of organic solvents through these reactors,” Flaherty said.
The Energy and Biosciences Institute through the EBI-Shell program and the National Science Foundation supported this research.
The paper “Solvent molecules form surface redox mediators in situ and cocatalyze oxygen reduction on Pd” is available from the U. of I. News Bureau.
National Science Foundation funds collaborative effort to reimagine creation of chemicals and fuels
A $2 million grant from the National Science Foundation will help a team of scientists at the University of Illinois develop ways to use renewable energy to remediate carbon dioxide emissions and generate chemical building blocks and liquid fuels.
The main idea of their proposal is to reimagine the manufacturing of chemicals and fuels as society shifts from using petroleum for these processes to renewable sources such as biomass and carbon dioxide. David Flaherty, professor of chemical and biomolecular engineering and Dow Chemical Faculty Scholar, said he and his colleagues have been laying the intellectual groundwork for this proposal over the past several years.
The team is comprised of five faculty members at the University of Illinois including Flaherty, Andrew Gewirth (chemistry), Paul Kenis (chemical and biomolecular engineering), Joaquín Rodríguez-López (chemistry), and Ashlynn Stillwell (civil and environmental engineering).
The team’s proposal was selected among hundreds of others in a rigorous review process for the grant through National Science Foundation’s Emerging Frontiers in Research and Innovation Research Projects program. Their concept uses renewable energy that comes off the grid from solar or wind power to drive an electrochemical reactor that performs two useful reactions simultaneously.
First, they use one side of the reactor to reduce carbon dioxide to form molecules currently used to make durable goods such as plastics. This will reduce domestic greenhouse gas emissions. However, reducing carbon dioxide requires a large amount of energy, because these reactions are thermodynamically unfavorable, Flaherty said. The challenge here is turning a stable molecule such as carbon dioxide into a much less stable molecule, he said.
“Another way to think about this is that we are trying to reverse the combustion process that is used to generate energy to move cars or produce electricity in power plants,” Flaherty said.
Second, the other side of the reactor partially oxidizes (or burns) renewable and abundant materials that are locally available. The energy captured from this process helps drive the reduction of carbon dioxide while the oxidation reaction produces useful chemicals.
“We have to change our approach for making building block chemicals,” Flaherty said. “How do we manufacture chemicals and create fuels and energy that will support all the things we enjoy doing but doing it in a distributed manner that aligns with the location of emerging resources? We need to move away from these hundred-acre petroleum refineries and find solutions that work at smaller scales.”
Kenis, the Elio E.Tarika Endowed Chair in Chemical Engineering, found a way to reduce carbon dioxide that would decrease the amount of renewable energy necessary for the process by up to 50 percent. He found that by coupling the carbon dioxide reduction with a more favorable type of chemistry on the other side of the reactor, the amount of energy necessary will greatly decrease.
“Electrolysis is seen as an option for industry to change over from the present plants to electrolysis processes,” Kenis said.
He added that, as part of the Paris Accord, the chemical industry is in an energy transition from 2020 to 2050 in which the dependency on fossil fuels and the associated carbon dioxide production must be decreased.
This is a win-win-win scenario, Flaherty said. If successful, they will efficiently reduce greenhouse gas emissions, produce renewable chemicals and fuels, and create new job opportunities for operators and engineers in an emerging distributive chemical manufacturing economy.
“We are going to learn so much from each other along the way,” Flaherty said. “We all have our own perspectives, our own expertise, and this is an awesome opportunity for us to tackle a critical challenge. In addition, this will be an excellent way for us to teach students a diverse set of skills they need to solve important societal problems.”
Congratulations to Chemical and Biomolecular Engineering PhD students who have been selected to receive fellowships from the National Science Foundation Graduate Research Fellowship Program. They include Paola Baldaguez Medina, Vasiliki “Aliki” Kolliopoulos, and Chris Torres.
The NSF program recognizes and supports individuals early in their graduate training in science, technology, engineering, and mathematics fields. The aim is to help ensure the vitality and diversity of the scientific and engineering workforce in the U.S. The program provides three years of support for students who have demonstrated their potential for significant research achievements in STEM or STEM education.
Baldaguez Medina completed her undergraduate education at the University of Puerto Rico at Mayagüez in 2019. While there, she conducted research in separation processes with Professor Hernández-Maldonado and spectroscopy with Professor Hernández-Rivera. She also had internships at the University of Minnesota through the NSF Research Experiences for Undergraduates (REU) program working on block-copolymers, and at the University of Florida with Professor Rinaldi on rheology studies.
A member of Assistant Professor Xiao Su’s research group at the University of Illinois, her work focuses on developing water remediation techniques via electrochemical mediated systems for the removal of anthropogenic organic contaminants of concern. She uses redox-polymers electrodes for pollutant binding through electrosorption. Developing an electrochemical separation method could impact society in numerous ways by providing energy effective and modular technologies for water purification, Baldaguez Medina said.
Kolliopoulos is a member of Professor Brendan Harley’s lab, which has been developing advances in tissue engineering. Craniofacial bone defects are common in the context of congenital, traumatic, and post-oncologic conditions. Such bone defects are often large in size and heal poorly, motivating regenerative medicine efforts. A particular barrier to regenerative healing is the significant immune and inflammatory response post injury which can inhibit cell recruitment, vascular remodeling, and new tissue biosynthesis. The Harley lab is developing a class of mineralized collagen biomaterials capable of meeting a wide range of design requirements for successful deployment into CMF bone defects, notably the ability to conformally fit complex defect geometries and support stem cell osteogenesis.
Kolliopoulos said she aims to understand the effect of scaffold biophysical properties (microstructure, stiffness, alignment, mineral morphology) on the recruitment and subsequent activation status of macrophages. Her ultimate goal is to demonstrate biomaterials capable of modulating the kinetics of the macrophage response post injury as a means to accelerate implant integration and subsequent bone regeneration. She completed her undergraduate studies at The Ohio State University. In 2018, while working in the Carlos Castro Lab, she received an honorable mention for the NSF GRFP for her work on DNA Origami.
Torres is a member of Associate Professor David Flaherty’s research group. He studies the catalytic role of solid-liquid interfaces and extended solvent networks for liquid-phase oxidation reactions. His research goal is to create design rules for catalysts which reduce the environmental impact of chemical industries. He completed his undergraduate education at the University of New Mexico.
Congratulations to graduate student Daniel Bregante, who was among a select group of Illinois students chosen for a Scholar Award from the ARCS Foundation.
Founded in 1958, the ARCS Foundation was established by and is run entirely by women. Its mission is to boost American leadership and aid advancement in science and technology. To address the country’s need for new scientists and engineers, the foundation provides unrestricted funding to help the country’s brightest graduate and undergraduate students create new knowledge and innovative technologies.
Bregante was among nine students in the state chosen for the award this year by the Illinois chapter of ARCS.
He is a member of Professor David Flaherty’s research group and is in the process of completing his dissertation, “Unraveling Inner- and Outer-Sphere Interactions that Impact Catalysis at the Liquid-Solid Interface.”
Molecular interactions at solid-liquid interfaces can have profound effects on the stability of species that form during catalysis and separations. These interactions become increasingly complex when the solvent and reactive species are confined within nanopores (<1 nm in diameter). Bregante’s research focuses on understanding how the structuring and restructuring of solvent molecules within these nanopores during a chemical reaction leads to changes in catalysis.
His findings have shown that the presence of polar “defects” within the pores of Lewis acid zeolites (i.e., an epoxidation catalyst) leads to increases in rates and selectivities for alkene epoxidation (a multi-billion-dollar industry) by a factor of 100. These results directly contradict conventional wisdom, that states hydrophobic pores leads to the greatest yields. His work has shown, non-intuitively, that the polarity mis-match between hydrophobic surface species and water leads to increases in stability, and thus higher rates. These findings and the conceptual framework developed will provide a broader understanding for interactions between solvents, surfaces, and reactive species, and provide a basis to understand how similar restructuring events may impact critical intermediates within other research fields.
Bregante will be given the award at the ARCS annual reception in Chicago in October. As part of the event, he and fellow scholars will present research posters at the reception.
The Department of Energy has selected 73 scientists from across the nation, including University of Illinois chemical and biomolecular engineering professor David Flaherty, to receive significant funding for research as part of its Early Career Research Program. The effort, now in its tenth year, is designed to bolster the nation’s scientific workforce by providing support to exceptional researchers during the crucial early career years, when many scientists do their most formative work.
Flaherty’s research project is entitled, “The Role of Cooperative Interactions Among Surfaces, Solvents, and Reactive Intermediates on Catalysis at Liquid-Solid Interfaces.” His lab focuses on the overlapping topics of catalysis, surface science, and materials synthesis.
“Supporting our nation’s most talented and creative researchers in their early career years is crucial to building America’s scientific workforce and sustaining America’s culture of innovation,” said Secretary of Energy Rick Perry in a release announcing the winners. “We congratulate these young researchers on their significant accomplishments to date and look forward to their achievements in the years ahead.”
To be eligible for the award, a researcher must be an untenured, tenure-track assistant or associate professor at a U.S. academic institution or a full-time employee at a Department of Energy national laboratory, who received a Ph.D. within the past 10 years. Research topics are required to fall within one of the Department’s Office of Science’s six major program offices: advanced scientific computing research, basic energy sciences, biological and environmental research, fusion energy sciences, high energy physics, and nuclear physics.
Awardees were selected from a large pool of university- and national laboratory-based applicants. Selection was based on peer review by outside scientific experts. Projects announced today are selections for negotiation of financial award. The final details for each project award are subject to final grant and contract negotiations between the Department of Energy and the awardees.
Under the program, university-based researchers will receive about $150,000 per year to cover summer salary and research expenses. For researchers based at Department of Energy national laboratories, where DOE typically covers full salary and expenses of laboratory employees, grants will be about $500,000 per year to cover year-round salary plus research expenses. The research grants are planned for five years.
A list of the 73 awardees, their institutions, and titles of research projects is available on the Early Career Research Program webpage https://science.osti.gov/early-career.
Chemical and Biomolecular Engineering Professor David Flaherty has received a new grant from the U.S. Army to develop design rules for solid catalysts for selective oxidations in the liquid-phase.
“To do that, we need to understand how to engineer the electronic structure of atomically dispersed transition metal active sites on oxide supports, which depend on the metals that form the active sites and the manner by which they share electrons with the extended surface of the support,” Flaherty said.
The motivation for the research comes from the wide-spread need for epoxides for the production of advanced materials, industrial solvents, and common consumer goods. The epoxidation of light alkenes (unsaturated hydrocarbons), produced in high volume from traditional fossil reserves and now shale gas, provides reactive building blocks that confer unique properties to polymers and surfactants. As a result, epoxides are produced on a massive scale; the global production and market for ethylene oxide and propylene oxide alone exceeds $45 billion each year.
“We should be able to control rates and selectivities for epoxidation reactions by electronically modifying the active sites for these reactions through use of different isolated metal atoms or by placing these metal atoms onto surfaces that act like ligands and change their electronic properties,” Flaherty said.
The new grant will fund the building of an apparatus that will allow the lab to characterize the structure of the active site and catalytic intermediates while the reaction is occurring, rather than relying on ex situ characterization methods that are unable to provide the needed information. This problem is well-known, according to Flaherty, as catalysts are dynamic, seemingly animate objects whose appearance and behavior depends strongly on their surroundings. Therefore, in situ characterization is required to learn about the active form of the catalyst.
“The general principles established under this project may enable rational catalyst design towards more reactive and selective catalysts,” said Dawanne Poree, program manager, chemical science, Army Research Office, an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. “These type of materials could be of great value to the Army, for efficient decomposition of hazardous chemicals for personnel and equipment protection.”
Since 2016, the Flaherty lab has received support from the Army Research Office for its research in this area. The funding for this project, and other projects inspired by the findings, has supported several graduate students and a postdoctoral researcher in the lab and has led to the publication of five articles in highly regarded journals (J. Am. Chem. Soc. ACS Catalysis, J. Catalysis) since 2017.
Flaherty joined the University of Illinois Department of Chemical and Biomolecular Engineering in 2012. He earned his Ph.D. from the University of Texas at Austin in 2010 and his post-doctoral work was completed at the University of California, Berkeley. His lab focuses on the overlapping topics of catalysis, surface science, and materials synthesis.
Congratulations to Dr. David Flaherty, recipient of the Early Career Award from the regional chapter of the American Vacuum Society.
Flaherty, an assistant professor in chemical and biomolecular engineering, received the award at the AVS Prairie Chapter symposium in Chicago earlier this month. He delivered the talk, “Non-Innocent Solvents, Hydrogen Transfer, Oxygen Dissociation on Nanoparticles during the Direct Synthesis of H2O2.”
The Flaherty Research Group develops new principles needed to design catalytic materials and systems for the sustainable production of consumer products and fuels. Flaherty, who joined the department in 2012, holds a BS from University of California, Berkeley and a PhD from the University of Texas at Austin.
Congratulations Prof. Flaherty!
Congratulations to Alayna Johnson, who has been named a Goldwater Scholar for the 2018-19 academic year!
Alayna is a sophomore majoring in chemistry. As a freshman, she joined the lab of Dr. David Flaherty, assistant professor in the Department of Chemical and Biomolecular Engineering, where her research with team members Daniel Bregante, Ami Patel, and Zeynep Ayla centers on the synthesis of epoxides, which are used to manufacture pharmaceuticals and plastics.
Noting the negative environmental impact of current methods of epoxide synthesis, Johnson elaborated on her team’s goals: “We’re hoping to engineer a catalyst that would allow industries to make epoxides in a new and greener manner. The project is a great combination of materials chemistry, catalysis, and environmental chemistry.”
“Alayna quickly developed skills in kinetic analysis and spectroscopy and has used these tools to show how we can tailor independently the electronic structure, porous structure, and hydrogen bonding interactions of inorganic materials to minimize the environmental impact of these oxidation reactions,” Flaherty said.
Flaherty called Alayna “a talented researcher, a brilliant student, and a truly enjoyable person to work with.”
“In my career, I have rarely seen this strong set of skills in such a young student. Alayna demonstrates her unstoppable drive and motivation in the way she approaches her classwork and research and excels in both,” he said.
Johnson’s experiences in the Flaherty lab also taught her more about herself and her research interests: “I’ve learned that while my interests certainly lie in pure science, an understanding of basic engineering and computational principles is invaluable.”
“The aspect I appreciate most about research is the intellectual freedom that comes with deciding which experiments to run, how to analyze the results, and what to do when they do not match the expected hypothesis. Within research, we get to experience the rare but incredibly rewarding feeling that comes from seeing the results of a well-designed experiment and learning something new about the world,” she said.
Johnson is one of three University of Illinois students to receive the prestigious honor. Read more from the Department of Chemistry.
Chemical and Biomolecular Engineering Professors David Flaherty and Brendan Harley have been named winners of the College of Engineering Dean’s Award for Excellence in Research. The award is given annually to a handful of engineering faculty in recognition of their research. Both will be honored at the college’s faculty awards ceremony on April 23.
Since they joined the department, Professors Harley and Flaherty have emerged as exceptional scientists and mentors, said Paul Kenis, William H. and Janet G. Lycan Professor and Department Head.
“It’s rewarding to see faculty recognized for their dedication to advancing science and leading and training research groups that are doing truly pioneering work. I expect they will continue to push the boundaries of their fields—Harley in biomaterials and Flaherty in heterogeneous catalysis,” Kenis said.
Flaherty, an assistant professor in the department, said he is inspired by the accomplishments of his research group and “thrilled to see the efforts of my students recognized in this way.”
The Flaherty Research Group develops new principles needed to design catalytic materials and systems for the sustainable production of consumer products and fuels.
“This difficult work is only possible because of the many forms of support we receive from our department and from the campus. Interactions with exceptional colleagues and the use of outstanding facilities are a few of the ways in which Illinois cultivates excellent research. I am honored for our group to be acknowledged along with the many brilliant engineers at Illinois,” he said.
Flaherty, who joined the department in 2012, holds a BS from University of California, Berkeley and a PhD from the University of Texas at Austin.
Harley said it was a humbling to receive such an award.
“There are amazing faculty doing innovative, meaningful research across this campus. To be recognized in this manner is a tribute to the outstanding trainees in my group who everyday work to make science bigger, more rigorous, and more inclusive,” said Harley, associate professor and Robert W. Schaefer Faculty Scholar. “It is also a reflection of my colleagues, collaborators, as well as the facilities and support staff on this campus who make our work possible.”
The Harley Research Group explores “how we can design biomaterials that can be implanted into the body to facilitate regeneration. But we also are developing biomaterials to examine biological processes outside of the body such as disease development and treatment.”
“Our challenge is to develop materials that mimic the complex, heterogeneous environment within the tissues and organs of our body,” Harley said. “We are excited about the potential of our work, such as finding new ways to predict drug resistance and patient-to-patient variability in cancer as well as to implants to regenerate complex musculoskeletal injuries such as composite (hard and soft tissue) craniofacial defects experienced by warfighters after high-energy impacts.”
Harley joined the department in 2008. He holds an SB degree from Harvard University and an SM/ScD from MIT.
Congratulations to Dr. Takahiko Moteki who won the 2017 Outstanding Young Researcher Award from the Society of Chemical Engineers, Japan for his work on ethanol conversion in the Flaherty Research Group.
The citation was for “Ethanol upgrading via cascade C-C bond formation reactions.” The work was performed with the Energy Biosciences Institute with financial support from BP.
Moteki was a postdoctoral researcher in Dr. Flaherty’s group from October 2014 to October 2016. His research focused on developing strategies to form renewable chemicals and fuels from ethanol created by the fermentation of biomass. His work elucidated the reaction networks responsible for oligomerizing ethanol derived intermediates into larger species and demonstrated methods to control these networks to selectively produce either long chain alcohols or aromatic compounds.
Dr. Moteki is now an assistant professor in the Department of Chemical System Engineering at the University of Tokyo.
Congratulations Professor Moteki!