College of Engineering News • Iowa State University

ISU chemical engineers discover key to unlocking performance of hydrogenation catalysts

Chemical engineering Ph.D. candidate Radhika Rao
CBE assistant professor Jean-Philippe Tessonnier

Carbon-supported metal nanoparticles have been used for decades as catalysts for the industrial production of chemicals. Yet, little is known about the role the carbon support plays on the performance of these materials. The choice of a support (activated carbon, carbon black, etc.) for a given process remains mostly based on trial and error. However, a recent study published in Nature Communications by researchers at Iowa State University now explains how carbon supports interact with precious metal nanoparticles and alter their electronic nature, thereby their catalytic performance.

Interfacial charge distributions in carbon-supported palladium catalysts” (DOI: 10.1038/s41467-017-00421-x) is the result of a three-year collaboration between Jean-Philippe Tessonnier, assistant professor of chemical and biological engineering, Ph.D. candidate Radhika Rao, and research teams at the University of Texas at Dallas, University of Florida, University of Strasbourg in France, Technical University of Denmark, and the Fritz Haber Institute of the Max Planck Society in Germany. The research was funded by the National Science Foundation Engineering Research Center for Biorenewable Chemicals (CBiRC).

“Carbon-supported noble metal catalysts have a broad array of applications and yet little is known about the strategies to rationally design them in order to obtain a target product from the reaction,” said Dr. Tessonnier. “We wanted to lay the foundation for understanding how carbons interact with metal nanoparticle catalysts. The results published in our Nature Communications article are a big step in this direction since they not only highlight the role of carbon supports on the catalyst’s performance, but also provide a simple methodology that can help leverage these properties for designing next-generation catalysts.”

Currently, hundreds of activated carbons and carbon blacks are commercially available. The common approach to designing carbon-supported catalysts consists of selecting a subset of materials based on the carbon manufacturers’ experience, and then testing them.

“This archaic trial and error selection process represents a serious roadblock to the further optimization of important industrial processes such as hydrogenation reactions,” said Tessonnier. “Our work opens new routes for increasing the selectivity of conventional palladium on carbon catalysts, thus decreasing waste. This is particularly important when dealing with renewable molecules obtained from biomass, where we want to selectively convert one chemical bond within a complex multifunctional chemical.”

Palladium on carbon is not only used for hydrogenation reactions, but it is also a common coupling catalyst that plays an important role for the production of pharmaceuticals and fine chemicals. Therefore, Iowa State researchers expect their work to have a broad impact spanning from the production of large volume petrochemicals to renewable chemicals from biomass and cancer therapeutics.