Au_130−xAg_x Nanoclusters with Non‐Metallicity: A Drum of Silver‐Rich Sites Enclosed in a Marks‐Decahedral Cage of Gold‐Rich Sites

Abstract

The synthesis and structure of atomically precise Au130−xAgx (average x=98) alloy nanoclusters protected by 55 ligands of 4‐tert‐butylbenzenethiolate are reported. This large alloy structure has a decahedral M54 (M=Au/Ag) core. The Au atoms are localized in the truncated Marks decahedron. In the core, a drum of Ag‐rich sites is found, which is enclosed by a Marks decahedral cage of Au‐rich sites. The surface is exclusively Ag−SR; X‐ray absorption fine structure analysis supports the absence of Au−S bonds. The optical absorption spectrum shows a strong peak at 523 nm, seemingly a plasmon peak, but fs spectroscopic analysis indicates its non‐plasmon nature. The non‐metallicity of the Au130−xAgx nanocluster has set up a benchmark to study the transition to metallic state in the size evolution of bimetallic nanoclusters. The localized Au/Ag binary architecture in such a large alloy nanocluster provides atomic‐level insights into the Au−Ag bonds in bimetallic nanoclusters.

Atomically Precise Alloy Nanoclusters

“…In terms of large-sized alloy NCs, Jin and co-workers synthesized Au 130Àx Ag x (TBBT) 55 (x =~98) in 2019. [168] Monometallic Au 130 (TBBT) 55 has not been reported. Therefore, Au 130Àx Ag x (TBBT) 55 (x =~98) is considered at ype of alloy NC formed for the first time by alloying Au and Ag.…”

“…Regarding the electronic structureo fA u 130Àx Ag x (TBBT) 55 ,o ptical absorption spectroscopy ( Figure 26 A) and ultrafastl aser spectroscopy (Figures 26 B-D) have revealed that it does not display metallicproperties. [168] 3. 84 were used as precursors because all of these Au n (SR) m NCs can be selectively synthesized or isolated.…”

Atomic Arrangement of AuAg Alloy on Carbon Support Enhances Electrochemical CO2 Reduction in Membrane Electrode Assembly

“…To understand the coordination of Ag atoms in the AuAg catalysts, which is an important factor for determining the surface energy and consequential catalytic activity, we performed EXAFS analysis (Figure S15). The initial AuAg-R and AuAg-B catalysts showed under-coordinated Ag atoms with different coordination numbers owing to the NP size and alloyed structure. − AuAg-R had a smaller coordination number than AuAg-B (Table S2), originating from the different particle sizes and alloy arrangements. TEM/SEM images and ECSA measurements showed that AuAg-R had a smaller particle size and higher surface area than AuAg-B (Figure and Figure S5).…”

Metal Nanoclusters in Point-of-Care Sensing and Biosensing Applications

“…Doping and alloying are employed for two important purposes. Because the costs of noble metals are similar, the combination of noble metals to each other is used for amplification purposes or to change the emitted light properties. ,, The combination of Au and Ag atoms is the most popular application of metal alloy NCs in biosensors. , There are reports that represented the amplification effect of Ag atoms on the PL of AuNCs. , Various PL biosensing strategies have been developed using bimetallic Ag/Au NCs including turn-off, − assembly induced emission, photoinduced election transferring, , and FRET- based strategies. This is due to their significant synergistic effect that boosts the analytical signals and the performance of the sensing surface .…”

“…Because the costs of noble metals are similar, the combination of noble metals to each other is used for amplification purposes or to change the emitted light properties. 432,521,522 The combination of Au and Ag atoms is the most popular application of metal alloy NCs in biosensors. 523,524 There are reports that represented the amplification effect of Ag atoms on the PL of AuNCs.…”