Kumar Bharat, Kawawaki Tokuhisa, Shimizu Nobuyuki, Imai Yukari, Suzuki Daiki, Hossain Sakiat, Nair Lakshmi V, Negishi Yuichi
Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
Nanoscale. 2020 May 14;12(18):9969-9979. doi: 10.1039/d0nr00702a.
To establish an ultimate energy conversion system consisting of a water-splitting photocatalyst and a fuel cell, it is necessary to further increase the efficiencies of the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the oxygen reduction reaction (ORR). Recently, it was demonstrated that thiolate (SR)-protected gold clusters, Aun(SR)m, and their related alloy clusters can serve as model catalysts for these three reactions. However, as the previous data have been obtained under different experimental conditions, it is difficult to use them to gain a deep understanding of the means to attain higher activity in these reactions. Herein, we measured the HER, OER, and ORR activities of Aun(SR)m and alloy clusters containing different numbers of constituent atoms, ligand functional groups, and heteroatom species under identical experimental conditions. We obtained a comprehensive set of results that illustrates the effect of each parameter on the activities of the three reactions. Comparison of the series of results revealed that decreasing the number of constituent atoms in the cluster, decreasing the thickness of the ligand layer, and substituting Au with Pd improve the activities in all reactions. Taking the stability of the cluster into consideration, [Au24Pd(PET)18]0 (PET = 2-phenylethanethiolate) can be considered as a metal cluster with high potential as an HER, OER, and ORR catalyst. These findings are expected to provide clear design guidelines for the development of highly active HER, OER, and ORR catalysts using Aun(SR)m and related alloy clusters, which would allow realization of an ultimate energy conversion system.
为了建立一个由光解水催化剂和燃料电池组成的终极能量转换系统，有必要进一步提高析氢反应（HER）、析氧反应（OER）和氧还原反应（ORR）的效率。最近，已证明硫醇盐（SR）保护的金簇Aun(SR)m及其相关合金簇可作为这三种反应的模型催化剂。然而，由于先前的数据是在不同的实验条件下获得的，因此难以用它们来深入了解在这些反应中获得更高活性的方法。在此，我们在相同的实验条件下测量了含有不同数量组成原子、配体官能团和杂原子种类的Aun(SR)m和合金簇的HER、OER和ORR活性。我们获得了一组全面的结果，阐明了每个参数对这三种反应活性的影响。对这一系列结果的比较表明，减少簇中组成原子的数量、减小配体层的厚度以及用Pd替代Au可提高所有反应的活性。考虑到簇的稳定性，[Au24Pd(PET)18]0（PET = 2-苯乙硫醇盐）可被视为一种具有高潜力的金属簇，可作为HER、OER和ORR催化剂。这些发现有望为使用Aun(SR)m和相关合金簇开发高活性HER、OER和ORR催化剂提供明确的设计指导方针，这将有助于实现一个终极能量转换系统。
