Xu Wen Wu, Gao Yi, Zeng Xiao Cheng
Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China. ; Department of Chemistry and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Sci Adv. 2015 Apr 24;1(3):e1400211. doi: 10.1126/sciadv.1400211. eCollection 2015 Apr.
New low-energy atomic structures of the thiolate-protected gold nanoparticle Au68(SH)32 are uncovered, where the atomic positions of the Au atoms are taken from the recent single-particle transmission electron microscopy measurement by Kornberg and co-workers, whereas the pattern of thiolate ligands on the gold core is attained on the basis of the generic formulation (or rule) of the "divide and protect" concept. Four distinct low-energy isomers, Iso1 to Iso4, whose structures all satisfy the generic formulation, are predicted. Density-functional theory optimization indicates that the four isomers are all lower in energy by 3 to 4 eV than the state-of-the-art low-energy isomer reported. Further analysis of the optimized structures of Au68(SH)32 shows that the structure of gold core in Iso1 to Iso4 is consistent with the experiment, whereas the positions of a few Au atoms at the surface of gold core are different. The computed optical absorption spectra of the four isomers are consistent with the measured spectrum. Computation of catalytic properties of Au68(SH)32 toward CO oxidation suggests that the magic number cluster can be a stand-alone nanoscale catalyst for future catalytic applications.
发现了硫醇盐保护的金纳米颗粒Au68(SH)32的新型低能原子结构，其中金原子的原子位置取自科恩伯格及其同事最近的单粒子透射电子显微镜测量结果，而金核上硫醇盐配体的模式是根据“分割与保护”概念的通用公式（或规则）得出的。预测了四种不同的低能异构体，即Iso1至Iso4，其结构均符合通用公式。密度泛函理论优化表明，这四种异构体的能量均比报道的最新低能异构体低3至4电子伏特。对Au68(SH)32优化结构的进一步分析表明，Iso1至Iso4中金核的结构与实验一致，而金核表面少数金原子的位置不同。这四种异构体的计算光学吸收光谱与测量光谱一致。对Au68(SH)32催化CO氧化性能的计算表明，这个神奇数字团簇可成为未来催化应用中的独立纳米级催化剂。
