University of Rochester Researchers Advance Tungsten Carbide as Precious Metal Alternative

Researchers at the University of Rochester have identified new methods to utilize tungsten carbide as a potential alternative to precious metal catalysts like platinum. These advancements address challenges in understanding tungsten carbide's surface structure and aim to enhance its application in industrial chemical reactions, plastic upcycling, and more accurate temperature measurement within chemical reactors.

"These advancements address challenges in understanding tungsten carbide's surface structure and aim to enhance its application in industrial chemical reactions, plastic upcycling, and more accurate temperature measurement within chemical reactors."

Catalytic Performance Enhancements

Tungsten carbide, an Earth-abundant metal commonly used in industrial machinery, has been explored as a substitute for precious metals often employed in the production of plastics and detergents. A primary challenge has been understanding its various atomic configurations, or phases, which influence its catalytic properties.

Marc Porosoff, an associate professor at the University of Rochester, along with Sinhara Perera and Eva Ciuffetelli, conducted research published in ACS Catalysis. They manipulated tungsten carbide particles at the nanoscale within chemical reactors using temperature-programmed carburization. This process allowed them to create catalysts in specific phases and evaluate their performance.

The study indicated that some less thermodynamically stable phases were more effective as catalysts.

"Specifically, the β-W₂C phase demonstrated effectiveness in converting carbon dioxide into precursors for chemicals and fuels, suggesting potential to rival platinum."

This ACS Catalysis study received support from the Sloan Foundation and the Department of Energy.

Application in Plastic Upcycling

Porosoff and his colleagues have also investigated tungsten carbide's utility in upcycling plastic waste. A study published in the Journal of the American Chemical Society, co-led by Linxao Chen from the University of North Texas and supported by Porosoff and URochester Assistant Professor Siddharth Deshpande, detailed its application in hydrocracking. Hydrocracking is a process that breaks down large molecules, such as polypropylene found in water bottles, into smaller molecules for the creation of new products.

"In comparisons with platinum catalysts for hydrocracking, tungsten carbide was found to be less costly and more than 10 times more efficient."

Its metallic and acidic properties, when in the correct phase, are suitable for breaking down polymer carbon chains. Unlike typical platinum-based catalysts, tungsten carbide does not possess micropores that restrict interaction with the long polymer chains present in single-use plastics. This development aims to improve plastic waste conversion processes and support a circular economy.

The Journal of the American Chemical Society research was funded by the National Science Foundation.

Advances in Temperature Measurement

Accurate measurement of catalyst surface temperatures is important for coordinating chemical reactions, which can either absorb (endothermic) or release (exothermic) heat. Existing measurement techniques often provide average readings that can deviate from actual surface temperatures by 10 to 100 degrees Celsius, potentially affecting the reproducibility and robustness of catalysis studies.

In collaboration with Andrea Pickel, researchers developed a new optical measurement technique, described in EES Catalysis.

"This method offers a more precise way to measure temperatures directly within chemical reactors."

Applying this technique to tandem catalysts, where an exothermic reaction powers an endothermic one, could minimize waste heat and lead to more efficient chemical engineering processes.

The EES Catalysis study was funded by the New York State Energy Research and Development Authority through the Carbontech Development Initiative.