Direct instrumental identification of catalytically active surface sites

Capturing catalytic hotspots in action

30 January 2018

Homing in on hotspots of activity on the surface of catalysts reveals the tiny defects that drive quicker reactions.

While electrocatalysts speed up chemical reactions, the reaction speed varies across the material’s surface. Pinpointing the most ‘active sites’ on a surface during a reaction, however, is difficult.

Researchers from the Technical University of Munich covered a platinum catalyst with an electrically conductive liquid. They applied a voltage to the catalyst and scanned its surface with a microscope to measure random ‘noise’ in the current passing between the tip of the microscope and the platinum at different locations. Noise was created as hydrogen ions in the liquid reacted with electrons to form hydrogen gas. The team pinpointed active sites to within 1 to 2 nanometres and found the most reactive points were located at tiny defects on the platinum surface.

These findings could help improve the efficiency of electrocatalysts for clean energy reactions, such as turning carbon dioxide emissions back into fuel.

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References

1. Nature 549, 74–77 (2017). doi: 10.1038/nature23661