An atomically precise Pt17 nanocluster: their electronic structure and high activity for a hydrogen evolution reaction

Pt nanoclusters (Pt NCs) approximately 1 nm in size show potential as catalysts owing to their large specific surface areas and unique electronic structures, which are influenced by quantum size effects. However, synthesizing Pt NCs with atomic precision under ambient conditions remains challenging, with [Pt17(CO)12(PPh3)8]z (z = 1+ or 2+; CO = carbon monoxide; PPh3 = triphenylphosphine) being the only current example of such a NC. It exhibits extraordinary stability, and its electronic structure and catalytic utility in a range of reactions are topics of widespread interest. In this study, we reveal its electronic structure and explore its catalytic activity in the hydrogen evolution reaction (HER). Our findings revealed that [Pt17(CO)12(PPh3)8]z possesses a discrete electronic structure, with the HOMO and LUMO primarily constituted by the s, p, and d orbitals of Pt; that a Pt17 NC-supported carbon-black catalyst (Pt17/CB) achieves 3.59-times the HER mass activity of a commercially available Pt/CB catalyst; and that the optimal electronic structure of the surface Pt atoms in Pt17/CB significantly enhances its HER activity. These insights underscore the potential of leveraging atomically precise Pt NCs in the design and development of highly active electrocatalysts for water splitting.