Single-Particle Hyperspectral Imaging Reveals Kinetics of Silver Ion Leaching from Alloy Nanoparticles
Single-Particle Hyperspectral Imaging Reveals Kinetics of Silver Ion Leaching from Alloy Nanoparticles
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DOI：
10.1021/acsnano.0c10150
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发表时间：
2021-04-22
期刊：
影响因子：
17.1
通讯作者：
Link, Stephan
中科院分区：
文献类型：
--
作者：
Al-Zubeidi, Alexander;Stein, Frederic;Link, Stephan
金-银合金纳米颗粒在多个应用中是令人感兴趣的，包括多相催化、光学传感和抗菌性能。惰性元素金充当银的稳定剂，以防止颗粒腐蚀，或者相反，控制抗菌银离子的释放动力学，以最小的细胞毒性获得长期功效。然而，很少有人知道银离子浸出的动力学从纳米粒子和它是如何与银含量，特别是不是在一个单一的颗粒水平。为了表征银离子从金-银合金纳米颗粒释放的动力学，我们采用了电子显微镜和单颗粒高光谱成像的组合，其具有足够快的采集速度以捕获不可逆的银离子浸出。单颗粒浸出曲线显示，由于与金的合金化以及两个浸出阶段，银离子浸出速率降低，速率常数具有很大的异质性。我们模拟的初始浸出阶段作为一个收缩颗粒的速率常数，指数依赖于银含量。第二，较慢的浸出阶段由合金的电化学氧化电势控制，合金的电化学氧化电势通过相对金含量的变化和银原子通过晶格的扩散而稳定地增加。有趣的是，具有相似尺寸和组成的单个纳米颗粒表现出完全不同的银离子浸出产率。大多数纳米颗粒完全释放银，但其中25%似乎阻止浸出。此外，纳米颗粒变得略微多孔。利用激光烧蚀技术制备纳米合金粒子，结合银离子浸出动力学研究，为纳米合金粒子的耐久性和生物活性设计提供了一种新的途径。
Gold-silver alloy nanoparticles are interesting for multiple applications, including heterogeneous catalysis, optical sensing, and antimicrobial properties. The inert element gold acts as a stabilizer for silver to prevent particle corrosion, or conversely, to control the release kinetics of antimicrobial silver ions for long-term efficiency at minimum cytotoxicity. However, little is known about the kinetics of silver ion leaching from bimetallic nanoparticles and how it is correlated with silver content, especially not on a single-particle level. To characterize the kinetics of silver ion release from gold-silver alloy nanoparticles, we employed a combination of electron microscopy and single-particle hyperspectral imaging with an acquisition speed fast enough to capture the irreversible silver ion leaching. Single-particle leaching profiles revealed a reduction in silver ion leaching rate due to the alloying with gold as well as two leaching stages, with a large heterogeneity in rate constants. We modeled the initial leaching stage as a shrinking-particle with a rate constant that exponentially depends on the silver content. The second, slower leaching stage is controlled by the electrochemical oxidation potential of the alloy being steadily increased by the change in relative gold content and diffusion of silver atoms through the lattice. Interestingly, individual nanoparticles with similar sizes and compositions exhibited completely different silver ion leaching yields. Most nanoparticles released silver completely, but 25% of them appeared to arrest leaching. Additionally, nanoparticles became slightly porous. Alloy nanoparticles, produced by scalable laser ablation in liquid, together with kinetic studies of silver ion leaching, provide an approach to design the durability or bioactivity of alloy nanoparticles.