Study Targets Atom Mobility to Improve Catalyst Performance
New research from a team of scientists at the University of California (UC), Santa Barbara; Stanford University and the University of Washington, is aiming to help chemical engineers design more efficient and durable industrial catalysts by directly measuring how metal ions move inside working catalytic materials.
Funded through the National Science Foundation’s Designing Materials to Revolutionize and Engineer our Future (DMREF) program, the collaboration focuses on understanding and controlling the mobility of positively charged ions, or cations, in solid catalysts.
According to Susannah Scott, a professor at UC who led the research, atom mobility has long been recognized as an important but difficult-to-observe feature of many catalytically active materials. “We’re now acknowledging that, in many cases, the dynamic behavior of atoms is critical to how catalysts function,” she said in a press statement. “They can migrate to create transient ensembles of atoms capable of catalyzing reactions that would not be possible otherwise.”
That same mobility, however, can also drive catalyst deactivation over time, causing loss of activity and selectivity. Scott said this has major economic and environmental implications for large-scale chemical manufacturing, where catalysts are expected to operate reliably for months or years. “There are enormous environmental and economic ramifications for these consequences of dynamic behavior, which is why we need to understand and control it better,” she added.
To track atom movement under operating conditions, the team is using high-energy X-ray techniques at the SLAC National Accelerator Laboratory, a U.S. Department of Energy national laboratory operated by Stanford University. Scott said the researchers have identified a signal that allows them to directly detect metal ion mobility while the catalyst is active.
Key to the work is the Debye–Waller factor, which provides a quantitative measure of how far atoms move from their equilibrium positions. By correlating this signal with catalytic performance, the researchers aim to intentionally design catalysts with controlled dynamic behavior rather than relying on trial-and-error discovery.
“We can’t just design static structures; we have to target their dynamic properties as well,” Scott noted.
The team is also studying how catalyst activation treatments, such as reduction in hydrogen, can trigger ion mobility and create active sites, as well as how controlled mobility may enable catalyst reactivation after deactivation. Scott noted that this could help address one of the biggest barriers to industrial adoption of new catalyst materials: lifetime, since industrial and commercial catalysts must perform for months or even years.
Beyond catalysis, the researchers expect the tools and insights developed in the project to apply to other technologies where ion motion is critical, including batteries.