Atomically Precise Au<sub>24</sub>Pt(thiolate)<sub>12</sub>(dithiolate)<sub>3</sub> Nanoclusters with Excellent Electrocatalytic Hydrogen Evolution Reactivity
Miyu Sera, Sakiat Hossain, S. Yoshikawa, Kana Takemae, Ayaka Ikeda, Tomoya Tanaka, Taiga Kosaka, Yoshiki Niihori, Tokuhisa Kawawaki, Yuichi Negishi
Abstract
[Au 24 Pt(C6) 18 ] 0 (C6 = 1-hexanethiolate) is twice as active as commercial Pt nanoparticles in promoting the electrocatalytic hydrogen evolution reaction (HER), thereby attracting attention as new HER catalysts with well-controlled geometric structures. In this study, we succeeded in synthesizing two new Au–Pt alloy nanoclusters, namely, [Au 24 Pt(TBBT) 12 (TDT) 3 ] 0 (TBBT = 4- tert -butylbenzenethiolate; TDT = thiodithiolate) and [Au 24 Pt(TBBT) 12 (PDT) 3 ] 0 (PDT = 1,3-propanedithiolate), by exchanging all the ligands of [Au 24 Pt(PET) 18 ] 0 (PET = 2-phenylethanethiolate) with mono- or dithiolates. Although [Au 24 Pt(TBBT) 12 (TDT) 3 ] 0 was synthesized serendipitously, a similar cluster, [Au 24 Pt(TBBT) 12 (PDT) 3 ] 0, was subsequently obtained by selecting the appropriate reaction conditions and optimal combination of thiolate and dithiolate ligands. Single crystal X-ray diffraction analyses revealed that the lengths and orientations of −Au(I)–SR–Au(I)– staples in [Au 24 Pt(TBBT) 12 (TDT) 3 ] 0 and [Au 24 Pt(TBBT) 12 (PDT) 3 ] 0 were different from those in [Au 24 Pt(C6) 18 ] 0, [Au 24 Pt(PET) 18 ] 0, and [Au 24 Pt(TBBT) 18 ] 0, and these subtle differences were reflected in the geometric and electronic structures as well as the HER activities of [Au 24 Pt(TBBT) 12 (TDT) 3 ] 0 and [Au 24 Pt(TBBT) 12 (PDT) 3 ] 0 . Accordingly, the HER activities of products [Au 24 Pt(TBBT) 12 (TDT) 3 ] 0 and [Au 24 Pt(TBBT) 12 (PDT) 3 ] 0 were, respectively, 3.5 and 4.9 times higher than those of [Au 24 Pt(C6) 18 ] 0 and [Au 24 Pt(TBBT) 18 ] 0 .