Marcel Schreier, who joined the Department of Chemical and Biological Engineering at the University of Wisconsin-Madison as an assistant professor in 2019, has ambitious plans to develop more efficient and sustainable ways to interconvert electrical and chemical energy.
Today, chemical transformations, such as the ones that create the plastics we use every day, are almost exclusively driven by heat derived from chemical energy stored in fossil fuel sources.
If those transformations could occur with sufficient efficiency using electricity that comes from renewable sources, the chemical industry might someday be able to substantially reduce its carbon footprint.
“If we believe that the energy system is moving away from using fossil fuels as energy carriers and more into using electricity, the moment will come when we need to interface the chemical and electrical energy streams,” says Schreier.
Interface is an apt word for the combination of electricity and chemicals, not only at the massive systems- and industry-level scale, but all the way down to molecular details.
When a conductor for electrons (called the electrode) meets a medium that can carry charged chemical species (known as an electrolyte), an electrochemical interface appears. And that interface can drive chemicals to transform using electricity.
During his PhD studies with Michael Grätzel at the École Polytechnique Fédérale de Lausanne in Switzerland, Schreier created devices that employ such electrochemical interfaces at the surface of semiconductors to harvest energy from sunlight and drive the transformation of carbon dioxide to more useful products.
In other words, the devices drove combustion backwards, using energy from the sun to create useful chemicals from carbon dioxide.
He was highly successful: Schreier still holds the world record for the most efficient solar-powered transformation of carbon dioxide into chemical energy.
And in the process of developing those devices, Schreier had an epiphany.
“While I started with the application goal, I realized the real beast we are missing in our field is a molecular understanding of how electricity drives catalytic processes.”
Consequently, understanding how the catalyst surface chemistry and the properties of the electrochemical interface impact catalysis was the main focus of Schreier’s postdoctoral work in the laboratory of Yogesh Surendranath at the Massachusetts Institute of Technology.
It’s a tricky question, complicated by the sheer number of parameters that may influence electrochemical reactions and the complicated nature of the chemistry taking place at the interface. That’s why Schreier opts for an approach using well-defined model systems to uncover the pathways employed by individual reactions.
“Electrochemical interfaces are so complicated that often the data is convoluted by several competing factors,” says Schreier. “Yet, when you intelligently design your experiments, you can parse out how individual parameters influence the rate of reactions at the interface to be confident that you are looking at the pathway that mediates the transformation in which you are interested.”
This approach has helped Schreier reveal surprising results and even upend previously held assumptions about the sequences of reactions that take place at electrochemical interfaces.
In particular, he was able to demonstrate surprising connections between the role of heat and electricity in driving reactions.
While at UW-Madison, Schreier’s group take a bottom-up approach, focusing on catalytic methods to introduce electricity as a driving force in industrially relevant chemical transformations.
It’s the continuation of a globe-spanning career arc, driven by Schreier’s wide-ranging interests inside and out of the physical sciences and engineering.
During his education, Schreier carried out research at BASF in Germany, where he worked on the electrolyte chemistry for Lithium-ion batteries. He also gained experience in process design at a chemical contract manufacturer, and later worked at the University of Alberta, where he investigated the mechanism of olefin oligomerization in Fischer-Tropsch refining. Later, he obtained his master’s degree at the Swiss Federal Institute of Technology in Zurich, but not before a stint at Caltech where he researched fuel cells.
“My research has always been at the intersection between renewable energy and the traditional chemical industry,” says Schreier.
At UW-Madison, he’s looking forward to building his lab and mentoring some of the outstanding graduate students in the CBE department.
“When I visited campus, I talked to students working in catalysis and I was impressed by their enthusiasm, inquisitive attitudes, and strong scientific backgrounds,” says Schreier. “I’m excited to work with these people.”
Author: Sam Million-Weaver