{"title":"二氧化碳吸附引发的钯/金核/壳纳米粒子的成分变化和表面等离子共振。","authors":"Aimeric Ouvrard, Natalia Alyabyeva, Abdoul-Mouize Zakaria, Keke Yuan, Céline Dablemont, Rémi Lazzari, Fabrice Charra, Bernard Bourguignon","doi":"10.1063/5.0231175","DOIUrl":null,"url":null,"abstract":"<p><p>Controlling composition and plasmonic response of bimetallic nanoparticles (NPs) is of great relevance to tune their catalytic activity. Herein, we demonstrate reversible composition and plasmonic response transitions from a core/shell to a bimetallic alloyed palladium/gold NP triggered by CO adsorption and sample temperature. The use of self-organized growth on alumina template film allows scrutinizing the impact of core size and shell thickness onto NP geometry and plasmonic response. Topography, molecular adsorption, and plasmonic response are addressed by scanning tunneling microscopy, vibrational sum frequency generation (SFG) spectroscopy, and surface differential reflectance spectroscopy, respectively. Modeling CO dipolar interaction and optical reflectivity corroborate the experimental findings. We demonstrate that probing CO adsorption sites by SFG is a remarkably sensitive and relevant method to investigate shell composition and follow in real-time Pd atom migration between the core and the shell. Pd-Au alloying is limited to the first two monolayers of the shell and no plasmonic response is found, while for a thicker shell, a plasmonic response is observed, concomitant with a lower Pd concentration in the shell. Above 10-4 mbar, at room temperature, CO adsorption triggers the shell restructuration, forming a Pd-Au alloy that weakens the plasmonic response via Pd migration from the core to the shell. NP annealing at 550 K, after pumping CO, leads to the desorption of remaining CO and gives enough mobility for Pd to migrate back inside the core and recover a pure gold shell with its original plasmonic response. This work demonstrates that surface stoichiometry and plasmonic response can be tuned by using CO adsorption and NP annealing.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.1000,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Change of composition and surface plasmon resonance of Pd/Au core/shell nanoparticles triggered by CO adsorption.\",\"authors\":\"Aimeric Ouvrard, Natalia Alyabyeva, Abdoul-Mouize Zakaria, Keke Yuan, Céline Dablemont, Rémi Lazzari, Fabrice Charra, Bernard Bourguignon\",\"doi\":\"10.1063/5.0231175\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Controlling composition and plasmonic response of bimetallic nanoparticles (NPs) is of great relevance to tune their catalytic activity. 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Pd-Au alloying is limited to the first two monolayers of the shell and no plasmonic response is found, while for a thicker shell, a plasmonic response is observed, concomitant with a lower Pd concentration in the shell. Above 10-4 mbar, at room temperature, CO adsorption triggers the shell restructuration, forming a Pd-Au alloy that weakens the plasmonic response via Pd migration from the core to the shell. NP annealing at 550 K, after pumping CO, leads to the desorption of remaining CO and gives enough mobility for Pd to migrate back inside the core and recover a pure gold shell with its original plasmonic response. 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引用次数: 0
摘要
控制双金属纳米粒子(NPs)的组成和等离子响应对调整其催化活性具有重要意义。在此,我们展示了由一氧化碳吸附和样品温度引发的从核/壳到双金属合金钯/金 NP 的可逆组成和等离子响应转变。利用氧化铝模板薄膜上的自组织生长,可以仔细研究核尺寸和壳厚度对 NP 几何形状和等离子响应的影响。通过扫描隧道显微镜、振动和频率发生(SFG)光谱和表面差分反射光谱分别研究了形貌、分子吸附和等离子响应。一氧化碳偶极相互作用模型和光学反射率证实了实验结果。我们证明,用 SFG 探测 CO 吸附位点是一种非常灵敏和相关的方法,可用于研究外壳成分并实时跟踪 Pd 原子在核心和外壳之间的迁移。Pd-Au 合金仅限于外壳的前两个单层,没有发现等离子响应,而对于较厚的外壳,则会观察到等离子响应,同时外壳中的 Pd 浓度较低。在室温下,当气压超过 10-4 毫巴时,CO 吸附会引发外壳重组,形成 Pd-Au 合金,通过 Pd 从内核向外壳迁移而削弱等离子响应。在抽吸 CO 之后,在 550 K 下进行 NP 退火会导致剩余 CO 的解吸,并为 Pd 迁移回核心内部提供足够的流动性,从而恢复具有原始等离子响应的纯金外壳。这项研究表明,利用 CO 吸附和 NP 退火可以调整表面化学计量和等离子响应。
Change of composition and surface plasmon resonance of Pd/Au core/shell nanoparticles triggered by CO adsorption.
Controlling composition and plasmonic response of bimetallic nanoparticles (NPs) is of great relevance to tune their catalytic activity. Herein, we demonstrate reversible composition and plasmonic response transitions from a core/shell to a bimetallic alloyed palladium/gold NP triggered by CO adsorption and sample temperature. The use of self-organized growth on alumina template film allows scrutinizing the impact of core size and shell thickness onto NP geometry and plasmonic response. Topography, molecular adsorption, and plasmonic response are addressed by scanning tunneling microscopy, vibrational sum frequency generation (SFG) spectroscopy, and surface differential reflectance spectroscopy, respectively. Modeling CO dipolar interaction and optical reflectivity corroborate the experimental findings. We demonstrate that probing CO adsorption sites by SFG is a remarkably sensitive and relevant method to investigate shell composition and follow in real-time Pd atom migration between the core and the shell. Pd-Au alloying is limited to the first two monolayers of the shell and no plasmonic response is found, while for a thicker shell, a plasmonic response is observed, concomitant with a lower Pd concentration in the shell. Above 10-4 mbar, at room temperature, CO adsorption triggers the shell restructuration, forming a Pd-Au alloy that weakens the plasmonic response via Pd migration from the core to the shell. NP annealing at 550 K, after pumping CO, leads to the desorption of remaining CO and gives enough mobility for Pd to migrate back inside the core and recover a pure gold shell with its original plasmonic response. This work demonstrates that surface stoichiometry and plasmonic response can be tuned by using CO adsorption and NP annealing.
期刊介绍:
The Journal of Chemical Physics publishes quantitative and rigorous science of long-lasting value in methods and applications of chemical physics. The Journal also publishes brief Communications of significant new findings, Perspectives on the latest advances in the field, and Special Topic issues. The Journal focuses on innovative research in experimental and theoretical areas of chemical physics, including spectroscopy, dynamics, kinetics, statistical mechanics, and quantum mechanics. In addition, topical areas such as polymers, soft matter, materials, surfaces/interfaces, and systems of biological relevance are of increasing importance.
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