Bottom-up precise synthesis of stable platinum dimers on graphene

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(2) dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt(1) 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(2) dimers are likely in the oxidized form of Pt(2)O(x). In hydrolytic dehydrogenation of ammonia borane, Pt(2) dimers exhibit a high specific rate of 2800 mol(H2) mol(Pt) (−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.