Surpassing the single-atom catalytic activity limit through paired Pt-O-Pt ensemble built from isolated Pt<sub>1</sub> atoms.

Wang, Hui; Liu, Jin-Xun; Allard, Lawrence F; Lee, Sungsik; Liu, Jilei; Li, Hang; Wang, Jianqiang; Wang, Jun et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

Despite the maximized metal dispersion offered by single-atom catalysts, further improvement of intrinsic activity can be hindered by the lack of neighboring metal atoms in these systems. Here we report the use of isolated Pt<sub>1</sub> atoms on ceria as "seeds" to develop a Pt-O-Pt ensemble, which is well-represented by a Pt<sub>8</sub>O<sub>14</sub> model cluster that retains 100% metal dispersion. The Pt atom in the ensemble is 100-1000 times more active than their single-atom Pt<sub>1</sub>/CeO<sub>2</sub> parent in catalyzing the low-temperature CO oxidation under oxygen-rich conditions. Rather than the Pt-O-Ce interfacial catalysis, the stable catalytic unit is the Pt-O-Pt site itself without participation of oxygen from the 10-30 nm-size ceria support. Similar Pt-O-Pt sites can be built on various ceria and even alumina, distinguishable by facile activation of oxygen through the paired Pt-O-Pt atoms. Extending this design to other reaction systems is a likely outcome of the findings reported here.