WashU engineer to design catalyst for wasted plant material

Since 1975, vehicles have included a catalyst in their catalytic converters that facilitates conversion of harmful pollutants into less harmful emissions before they leave a vehicle's exhaust system. A chemical engineer at Washington University in St. Louis is designing a new type of catalyst that turns wasted plant material into a product that can be used for renewable chemical and material production.

Marcus Foston

Marcus Foston, assistant professor of energy, environmental & chemical engineering in the School of Engineering & Applied Science, will use a five-year, $250,000 grant from the American Chemical Society Herman Frasch Fund for Chemical Research to find a technology that will create a greater value for lignin, a byproduct of paper and bioethanol production, to be used to make other products.

"Waste biomass and agricultural residues are produced in enormous quantities globally, with up to 1.3 billion dry tons of biomass per year in the U.S. alone," Foston said. "This proposed catalytic conversion system for lignin will allow for more complete use of biomass, enhancing the use of waste produced during the processing of carbohydrates extracted from agricultural and energy crops."

Biorefineries employ integrated processes to use all of the materials and energy contained in biomass, including lignin, a component of the plant cell wall that makes up plants' defensive and support structures. However, by its design, lignin is very strong and rigid, making it difficult to break down. Foston's expertise is in breaking down lignin, which is usually thrown away or burned, into useful products.

"One of the major reasons lignin conversion is difficult and so challenging to investigate on a fundamental level is the high level of structural diversity that inherently defines lignin," Foston said. "The structure of lignin varies from species to species, or even from plant to plant, and is influenced by genetic, developmental and environmental factors."

Some of Foston's previous research has shown some benefit in breaking down lignin into an alcohol using a copper-doped porous metal oxide catalyst (CuPMO) without forming residues such as coke and char. This catalyst creates the hydrogen needed for efficient lignin deconstruction by a method called alcohol reforming. In preliminary research, Foston has found that a nickel-doped porous metal oxide catalyst (NiPMO) broke down lignin much faster than the CuPMO, but does not catalyze alcohol reforming to produce the hydrogen required for lignin deconstruction.

In the new research, Foston seeks to determine how combining the two metals into one catalyst will affect ethanol reforming and lignin deconstruction. His lab will design a nickel- and copper-doped porous metal oxide catalyst (NiCuPMO) as well as develop a conversion process using the catalyst and ethanol to convert lignin into products that are usable for other products.

Ultimately, among other goals, Foston wants to understand the role that different transition metals have in a multiple metallic catalyst to reform alcohol and catalyze hydrogen production and to break down lignin with that hydrogen and catalyze chemical production.

The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 90 tenured/tenure-track and 40 additional full-time faculty, 1,200 undergraduate students, 1,200 graduate students and 21,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.