LSU ChE Professor Dr. Kunlun Ding Identifies Active Sites in Copper-Zeolite Catalysts

A research team led by LSU associate Professor Dr. Kunlun Ding has uncovered new insights into the structure of copper-zeolite catalysts. Using a nontraditional research approach, they identified monomeric copper species, small singular copper atoms, that may play an important role in catalyst performance, helping researchers better understand how copper-zeolite catalysts function. This discovery could ultimately improve the performance in chemical processes regarding emissions reduction and methane conversion.

Ding’s interest in catalysis began early in his academic career. While earning his Ph.D., he studied physical chemistry. During his first postdoctoral position at the University of California, Santa Barbara (UCSB), Ding began studying catalysis for methane conversion and the challenges associated with the process. This work eventually led him to his research on copper-zeolite catalysts. 
Copper-zeolite catalysts are already used in selective catalytic reduction (SCR) systems in 18-wheelers to help reduce harmful nitrogen oxide (NOx) emissions. Researchers are also studying these catalysts for methane conversion, a process that has not yet been commercialized. Understanding how these catalysts work at a molecular level has been a challenge in these processes. 

Ding and his research team used a unique approach to study the structure of copper-zeolite catalysts. Instead of relying only on traditional visible Raman spectroscopy, they used a deep-UV laser and detected monomeric copper species that had previously been difficult to observe.  Previous research suggested that dimeric copper species, two copper atoms together, were responsible for the catalyst’s active sites, which is where the chemical reaction happens. Ding’s research instead found that monomeric copper species play an important role as active sites. 

These methods were made possible by the collaboration of 4 institutions: LSU, the University of Alabama, Oak Ridge National Laboratory, and Lehigh University. LSU led the effort, Alabama conducted theoretical modeling, Lehigh contributed to the UV experiments, and Oak Ridge National Laboratory supported the Raman experiments. “It's really a team effort,” Ding said, “With this combination of many different efforts, we can put the story together and understand the catalyst better.” 

Future applications of the research could include improving the performance of catalysts used for NOx reduction and developing catalysts that could make methane conversion commercially viable. Ding also hopes the combined spectroscopy method can be applied to other catalyst systems and chemical processes. “We are very excited about this general topic of using the combination of many different spectroscopies to identify the site,” Ding said. “Then, we can develop some special material chemistry to develop new catalysts and ultimately make the catalysts better in all different kinds of chemical processes.”