Bottom-up precise synthesis of stable platinum dimers on graphene.

Yan, Huan; Lin, Yue; Wu, Hong; Zhang, Wenhua; Sun, Zhihu; Cheng, Hao; Liu, Wei; Wang, Chunlei et al. · Nat Commun · 2017

basic_science · Level V

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Abstract

Supported metal clusters containing only a few atoms are of great interest. Progress has been made in synthesis of metal single-atom catalysts. However, precise synthesis of metal dimers on high-surface area support remains a grand challenge. Here, we show that Pt<sub>2</sub> dimers can be fabricated with a bottom-up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt<sub>1</sub> single-atom deposition and attaching a secondary Pt atom selectively on the preliminary one. Scanning transmission electron microscopy, x-ray absorption spectroscopy, and theoretical calculations suggest that the Pt<sub>2</sub> dimers are likely in the oxidized form of Pt<sub>2</sub>O<sub>x</sub>. In hydrolytic dehydrogenation of ammonia borane, Pt<sub>2</sub> dimers exhibit a high specific rate of 2800 mol<sub>H2</sub> mol<sub>Pt</sub><sup>-1</sup> min<sup>-1</sup> at room temperature, ~17- and 45-fold higher than graphene supported Pt single atoms and nanoparticles, respectively. These findings open an avenue to bottom-up fabrication of supported atomically precise ultrafine metal clusters for practical applications.