Highly Stable and Reactive Platinum Single Atoms on Oxygen Plasma-Functionalized CeO Surfaces: Nanostructuring and Peroxo Effects.

Atomically dispersed precious metals on oxide supports have recently become increasingly interesting catalytic materials. Nonetheless, their non-trivial preparation and limited thermal and environmental stability constitutes an issue for their potential applications. Here we demonstrate that an oxygen plasma pre-treatment of the ceria (CeO ) surface serves to anchor Pt single atoms, making them active and resistant towards sintering in the CO oxidation reaction. Through a combination of experimental results obtained on well-defined CeO films and theory, we show that the O plasma causes surface nanostructuring and the formation of surface peroxo (O ) species, favoring the uniform and dense distribution of isolated strongly bonded Pt atoms. The promotional effect of the plasma treatment was further demonstrated on powder Pt/CeO catalysts. We believe that plasma functionalization can be applied to other metal/oxide systems to achieve tunable and stable catalysts with a high density of active sites.