Synchrotron shows that defects make catalysts

RESEARCHERS at the Hebrew University of Jerusalem in Israel have shown that it is defects at the edge of precious metal particles which given them catalytic activity.

Defects have long been hypothesised as the reason for a catalyst’s efficacy, as high catalytic reactivity is known to correlate to a high level of defects, but it has not previously been proven. Now Elad Gross and his colleagues at the Center for Nanoscience and Nanotechnology, have used Lawrence Berkeley National Laboratory’s Advanced Light Source (ALS) synchrotron to observe the catalyst in action. The ALS infrared probe can identify individual atoms and the locations where a reaction is taking place.

Gross and the team used the ALS probe to look at single platinum particles like those used in industrial catalysts. The researchers found that the chemical reactions largely happen on the edge of the particles. The centres of the particles are less reactive.

The images from the ALS showed that the platinum atoms at the edge of the particles are disordered and rough, while the centres are smooth. The atoms at the edges, therefore, are not completely surrounded by other platinum atoms and can form stronger interactions with reactant molecules to activate them and initiate chemical reactions.

“Our findings provide insights about the ways by which the atomic structure of catalysts controls their reactivity. This knowledge can direct the design of improved catalysts that will make chemical process greener, by decreasing the amount of energy that is consumed in the process and preventing the formation of unwanted, potentially hazardous, products,” said Gross.

Nature DOI: 10/bw7r