Ammonium nitrate is a fertilizer that helps feed the world’s population, but it comes with a catch: The runoff from agricultural use and industrial production is full of pollutants like nitrate. Removing nitrate from wastewater is costly and energy-intensive.
Jason Bates , an assistant professor of chemical engineering at the University of Virginia School of Engineering and Applied Science, has won a National Science Foundation CAREER Award of $702,370 to investigate an alternative that could convert the nitrate into valuable chemical products with renewably sourced electricity. The prestigious award supports early-career faculty who show potential as role models in research and education.
The conversion involves electrocatalysis, a process where chemical reactions occur at the surface of a conductive material, or electrode. The problem is, multiple reactions happen at once, resulting in poor efficiency and unwanted by-products.
That undermines the benefit of catalysis engineering, the science of designing materials (catalysts) to optimize chemical reactions . In industry and manufacturing, catalysis is used to reduce the costs, energy consumption and environmental impact of making products like gasoline, clothing and food.
Bates’ project could improve nitrate conversion, leading to new water treatment technologies. For example, a farmer could convert nitrate from field runoff back to ammonia using an on-site electrocatalytic device powered by solar or wind energy.
Turning waste into raw ingredients might help rebalance natural processes like the nitrogen cycle, which can’t keep up with fertilizer use. We can’t stop feeding people, but Bates believes technologies like nitrate conversion can give Mother Nature a much-needed hand.
To that end, a bigger goal is discovering new ways to study electrocatalytic reactions using methods from a related field.
“This project is all electrocatalysis, but we’re using tools and concepts from thermal catalysis to lead the field in new directions,” said Bates, who has expertise in both areas from his Ph.D. and postdoctoral training.
Electrocatalysis and thermal catalysis largely developed separately, and it’s only recently that researchers began crossing over. Bates is part of that wave, which helped bring him to UVA as a strategic hire under the University’s Catalysis Initiative for Clean Energy and Chemicals .
“Jason is a talented, creative researcher who thrives on bringing fresh ideas to tough societal challenges,” said Ayman Karim, Olsen Professor and chair of the chemical engineering department. “His CAREER Award exemplifies that spirit as well as his and UVA’s strengths in catalysis research aimed at solving some of our most pressing problems.”
While thermal catalysis processes in manufacturing are effective — and important for supporting societal needs — many are already highly optimized.
“The ammonia synthesis catalyst is a great example of this,” Bates said.
“It takes hundreds of degrees Celsius and tremendous pressure. That requires expensive equipment and a big chemical plant, whereas these technologies that use renewable electricity we envision could be applied at a smaller scale, but everywhere — scaling out instead of up in a centralized location.”
The concept could eventually be applied to other chemical products that rely on catalysis, potentially reducing demands on large-scale manufacturing. But it has to start with learning how to decode the reactions at the electrode surface.
One technique that’s used successfully to study reactions in thermal catalysis, but rarely in electrocatalysis, is modulation excitation spectroscopy. Like all spectroscopy, it uses light absorbed by the material you’re studying to take precise measurements that allow you to characterize the material’s physical and chemical properties.
Graduate student Zayan Akmal will apply this spectroscopic method to examine catalytic reactions in an electrochemical flow cell, a device containing a catalyst immersed in a solution that flows past it. This allows rapid exchange of charged particles in the solution, or electrolytes, in contact with the catalyst. An instrument wired to the cell drives the reaction with electrical current.
The researchers can control — or “modulate” — specific inputs to the cell dynamically, such as the voltage level, and, importantly, the quantity and type of electrolytes interacting with the catalyst.
“We’re doing this over time, so we’re not just taking a snapshot,” Bates said. “We’re taking a movie of the surface in a way, but it’s not an image. It’s a data set resulting from the interaction of the light with the catalyst surface.”
Akmal explained that modulation excitation selectively reveals molecular details in the data that conventional spectroscopy could miss.
“Identifying the roles of individual chemical species within a complex network of reactions is the true essence of this method,” he said. “It helps us map which interactions resulted in the fastest route from point A, in our case nitrate, to the end point, which is ammonia.”
Another graduate student, Isaac Boateng, will also conduct experiments using conventional electrochemical cells and kinetic modeling approaches inspired by thermal catalysis.
“There’s a whole slew of technologies that could leverage alternative energy sources to make products we need,” Bates said. “Developing the fundamental science to make industrial technologies like this possible could solve a lot more than the nitrate problem.”
Bates’ project includes two educational components beyond training the undergraduate and graduate researchers in his lab.
He is working with UVA’s First-Year Engineering Center to expand the chemical engineering design project options in Engineering Foundations, a required course, to include electrochemical water treatment systems.
And, in 2027, his lab will begin offering paid summer research experiences to high school students through Charlottesville’s Community Attention Youth Internship Program .
They are the ones who will bring his work to fruition, he said.
“As faculty, our greatest impact isn’t published papers or the proposals that get funded,” Bates said. “It’s producing students who will go out in the world and develop these technologies.”