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1. Core Size Conversion of Au ₃₂₉ (SCH ₂ CH ₂ Ph) ₈₄ to Au ₂₇₉ (SPh- t Bu) ₈₄ Nanomolecules

   https://doi.org/10.1021/acs.jpcc.9b01953  

   Eswaramoorthy, Senthil Kumar; Sakthivel, Naga Arjun; Dass, Amala (March 2019, The Journal of Physical Chemistry C)
2. Molecular Flexibility in Solvated Crystals of the Dimer, Au ₂ (μ-1,2-bis(diphenylphosphino)ethane) ₂ I ₂ , with Three-Coordinate Gold(I)

   https://doi.org/10.1021/acs.inorgchem.4c00783  

   Costa, Sarah; Aristov, Michael M; Lim, Sang Ho; Chui, Sarah M; Espinoza, Katelyn A; Olmstead, Marilyn M; Fettinger, James C; Berry, John F; Balch, Alan L (July 2024, Inorganic Chemistry)

   We report the ability to trap the dimer Au2(μ-dppe)2I2 (dppe is 1,2- bis(diphenylphosphino)ethane) with different separations between the three-coordinate gold ions in crystalline solvates. All of these solvates ((Au2(μ-dppe)2I2·4(CH2Cl2) (1), Au2(μ- dppe)2I2·2(CH2Cl2) (2), the polymorphs α-Au2(μ-dppe)2I2·2(HC(O)NMe2) (3) and β- Au2(μ-dppe)2I2·2(HC(O)NMe2) (4), and Au2(μ-dppe)2I2·4(CHCl3) (5)) along with polymeric {Au(μ-dppe)I}n·n(CHCl3) (6)) originated from the same reaction, only the solvent system used for crystallization differed. In the different solvates of Au2(μ-dppe)2I2, the Au···Au separation varied from 3.192(1) to 3.7866(3) Å. Computational studies undertaken to understand the flexible nature of these dimers indicated that the structural differences were primarily a result of crystal packing effects with aurophillic interactions having a minimal effect. 

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3. In situ study of nucleation and growth dynamics of Au nanoparticles on MoS ₂ nanoflakes

   https://doi.org/10.1039/c8nr03519a  

   Song, Boao; He, Kun; Yuan, Yifei; Sharifi-Asl, Soroosh; Cheng, Meng; Lu, Jun; Saidi, Wissam A.; Shahbazian-Yassar, Reza (January 2018, Nanoscale)

   Two-dimensional (2D) substrates decorated with metal nanoparticles offer new opportunities to achieve high-performance catalytic behavior. However, little is known on how the substrates control the nucleation and growth processes of the nanoparticles. This paper presents the visualization of dynamic nucleation and growth processes of gold nanoparticles on ultrathin MoS 2 nanoflakes by in situ liquid-cell transmission electron microscopy (TEM). The galvanic displacement resulting in Au nuclei formation on MoS 2 was observed in real time inside the liquid cell. We found that the growth mechanism of Au particles on pristine MoS 2 is in between diffusion-limited and reaction-limited, possibly due to the presence of electrochemical Ostwald ripening. A larger size distribution and more orientation variation is observed for the Au particles along the MoS 2 edge than on the interior. Differing from pristine MoS 2 , sulfur vacancies on MoS 2 induce Au particle diffusion and coalescence during the growth process. Density functional theory (DFT) calculations show that the size difference is because the exposed molybdenum atoms at the edge with dangling bonds can strongly interact with Au atoms, whereas sulfur atoms on the MoS 2 interior have no dangling bonds and weakly interact with gold atoms. In addition, S vacancies on MoS 2 generate strong nucleation centers that can promote diffusion and coalescence of Au nanoparticles. The present work provides key insights into the role of 2D materials in controlling the size and orientation of noble metal nanoparticles vital to the design of next generation catalysts. 

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4. N -Heterocyclic Carbene Polymer-Stabilized Au Nanowires for Selective and Stable Reduction of CO ₂

   https://doi.org/10.1021/jacs.5c04742  

   Chen, Yuliang; Wei, Kecheng; Duan, Hanyi; Sun, Haobo; Yu, Ziyan; Zohaib, Ahsan; Zhu, Pengcheng; He, Jie; Sun, Shouheng (April 2025, Journal of the American Chemical Society)

   The structural stability of nanocatalysts during electrochemical CO2 reduction (CO2RR) is crucial for practical applications. However, highly active nanocatalysts often reconstruct under reductive conditions, requiring stabilization strategies to maintain activity. Here, we demonstrate that the N-heterocyclic carbene (NHC) polymer stabilizes Au nanowire (NW) catalysts for selective CO2 reduction to CO over a broad potential range, enabling coupling with Cu NWs for one-step tandem conversion of CO2 to C2H4. By combining the hydrophobicity of the polystyrene chain and the strong binding of NHC to Au, the polymer stabilizes Au NWs and promotes CO2RR to CO with excellent selectivity (>90%) across −0.4 V to −1.0 V (vs RHE), a significantly broader range than unmodified Au NWs (−0.5 V to −0.7 V). Stable CO2RR at negative potentials yields a high jCO of 142 A/g Au at −1.0 V. In situ ATR-IR analysis indicates that the NHC polymer regulates the water microenvironment and suppresses hydrogen evolution at high overpotential. Moreover, NHC-Au NWs maintain excellent stability during 10 h of CO2RR testing, preserving the NW morphology and catalytic performance, while unmodified NWs degrade into nanoparticles with reduced activity and selectivity. NHC-Au NWs can be coupled with Cu NWs in a flow cell to catalyze CO2RR to C2H4 with 58% efficiency and a partial current density of 70 mA/cm2 (overall C2 product efficiency of 65%). This study presents an adaptable strategy to enhance the catalyst microenvironment, ensure stability, and enable efficient tandem CO2 conversion into value-added hydrocarbons. 

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5. Self-assembled HfO ₂ -Au nanocomposites with ultra-fine vertically aligned Au nanopillars

   https://doi.org/10.1039/D2NR03104C  

   Zhang, Yizhi; Zhang, Di; Liu, Juncheng; Lu, Ping; Deitz, Julia; Shen, Jianan; He, Zihao; Zhang, Xinghang; Wang, Haiyan (August 2022, Nanoscale)

   Oxide-metal-based hybrid materials have gained great research interest in recent years owing to their potential for multifunctionality, property coupling, and tunability. Specifically, oxide-metal hybrid materials in a vertically aligned nanocomposite (VAN) form could produce pronounced anisotropic physical properties, e.g. , hyperbolic optical properties. Herein, self-assembled HfO 2 -Au nanocomposites with ultra-fine vertically aligned Au nanopillars (as fine as 3 nm in diameter) embedded in a HfO 2 matrix were fabricated using a one-step self-assembly process. The film crystallinity and pillar uniformity can be obviously improved by adding an ultra-thin TiN-Au buffer layer during the growth. The HfO 2 -Au hybrid VAN films show an obvious plasmonic resonance at 480 nm, which is much lower than the typical plasmonic resonance wavelength of Au nanostructures, and is attributed to the well-aligned ultra-fine Au nanopillars. Coupled with the broad hyperbolic dispersion ranging from 1050 nm to 1800 nm in wavelength, and unique dielectric HfO 2 , this nanoscale hybrid plasmonic metamaterial presents strong potential for the design of future integrated optical and electronic switching devices. 

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