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 Pt2 dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt1 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 Pt2 dimers are likely in the oxidized form of Pt2Ox. In hydrolytic dehydrogenation of ammonia borane, Pt2 dimers exhibit a high specific rate of 2800 molH2 molPt −1 min−1 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.
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机译：负载的仅包含几个原子的金属簇非常令人感兴趣。金属单原子催化剂的合成已取得进展。然而，在高表面积载体上精确合成金属二聚体仍然是一个巨大的挑战。在这里，我们显示可以通过自上而下的方法在石墨烯上使用原子层沉积，通过适当的成核位点生成，Pt1单原子沉积以及在初级原子上选择性地连接次级Pt原子，来制造Pt2二聚体。扫描透射电子显微镜，x射线吸收光谱和理论计算表明，Pt2二聚体可能以Pt2Ox的氧化形式存在。在氨硼烷的水解脱氢中，Pt2二聚体在室温下具有2800 molH2 molPt -1 min -1 的高比值，比高约17倍和45倍石墨烯分别负载Pt单原子和纳米颗粒。这些发现为自底向上制造支持原子精确超细金属团簇的实际应用开辟了道路。
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