Advances in oil refining, drug and chemical production and environmental protection, says Israel E. Wachs, depend on understanding the relationship between a material’s molecular structures and its catalytic properties.
Wachs, the G. Whitney Snyder Professor of chemical engineering, has spent much of his career investigating that relationship. He has written more than 300 articles, he holds three dozen patents and he is one of the most frequently cited researchers in his field. Wachs’ article “Recent conceptual advances in the catalysis science of mixed metal oxide catalytic materials,” published in 2005 in Catalysis Today, was the fifth most-cited paper in the field of catalysis that year and one of the 50 most-cited papers published in Elsevier’s catalysis journals in 2004–08.
Catalysis, says Wachs, is indispensable to making products with as little waste as possible. Without the right catalysts in petroleum, chemical, pharmaceutical or environmental processes, he says, chances are you will not end up with an economical product. Thus, industry is counting on researchers to develop catalysts for new applications.
Wachs’ patents include a process used in paper mills that converts methanol, a costly pollutant, into formaldehyde, a chemical that can be used in making particle board.
Sequence is vital to Wachs. He prefers to conduct fundamental studies of catalysts before testing them.
“Few take this approach or get as detailed as I do,” he says. “That’s why we discover not only new catalysts, but also new phenomena that help produce better catalysts. Because of this approach, we know at the molecular level how catalysts work and how they change in different environments. This understanding can give us the ability to make products faster and with less waste.”
In one patented discovery, Wachs and his team found that by spreading metal oxides onto a stream of alcohol, they could make catalysts from pure natural materials without adding expensive precursors. This allows the catalysts, which usually lose their potency after a few years, to be rejuvenated.
Another discovery promises to help control the emission of nitrogen oxide (NOx) from autos and electric power plants. NOx is a greenhouse gas that also produces ground-level ozone pollution and acid rain. Funded by NSF, Wachs and his colleagues at Lehigh, Rice University and the University of Virginia are developing a molecularly engineered nanocatalyst that efficiently converts NOx into benign nitrogen and water.
Wachs utilizes Raman spectroscopy and other advanced molecular techniques to see in real time how molecules and catalytic active sites interact while simultaneously analyzing reaction products online. This enables his group to determine directly the relationships between catalytic structure and catalytic activity. This technique has been termed operando spectroscopy, and Wachs appropriately named his Lehigh lab the Operando Molecular Spectroscopy and Catalysis Research Laboratory.
Wachs confesses to a zeal for detail.
“I find it intellectually satisfying. I get answers much faster by figuring out what makes a catalyst tick than by testing 1,000 catalysts.”
His Ph.D. adviser at Stanford, Wachs says, exposed him to molecular-level research. His work at Exxon helped him understand complex industrial catalysts.
“I didn’t understand how complex catalysts worked, and the only way to figure that out was to move on to Lehigh, where I would enjoy the academic freedom to ask and pursue fundamental questions.”
In 2008, Wachs was chosen by the American Chemical Society to receive the George A. Olah Award in Hydrocarbon or Petroleum Chemistry for his contributions to catalysis over 30 years. Olah was the 1994 Nobel laureate in chemistry.
“Being at Lehigh, I interact with auto, mineral, chemical, pharmaceutical, environmental and petroleum companies,” says Wachs. “It’s a broader experience. What I enjoy most is the ability to establish the fundamental relationships between molecular structure and catalytic performance. If I know that relationship, I can design new and novel catalysts.”
