Science 350, 189–192 (2015)
Catalytic metals have been widely applied for the enhancement of important chemical processes. One prominent example is the treatment of exhaust gas to limit carbon monoxide emission, using platinum dispersed on a solid support to catalyse oxidation and water–gas shift reactions. However, the precise nature of the catalytic mechanism, and the potential involvement of either single atoms or nanoparticles of platinum, are still questioned. Now, Kunlun Ding and colleagues present a spectroscopic quantification of platinum atoms and nanoparticles on solid supports and study their respective catalytic contributions. They used infrared spectroscopy to monitor carbon monoxide adsorption on supports with varying platinum contents, and by identifying separate signals for adsorption to either atomic or nanocluster platinum, they were able to accurately quantify these different species. Only the carbon monoxide adsorbed on nanoclusters was observed to participate in the catalytic reaction on exposure to oxygen or water at low temperatures, while single atoms remained unreactive. This provides an important insight for future catalyst optimization.
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