聚乙烯吡咯烷酮 (PVP) 作为封端和结构导向剂在 Pt 纳米立方体形成中的作用,Nanoscale Advances

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聚乙烯吡咯烷酮 (PVP) 作为封端和结构导向剂在 Pt 纳米立方体形成中的作用
Nanoscale Advances ( IF 4.6 ) Pub Date : 2019-06-24 , DOI: 10.1039/c9na00186g
I A Safo ₁ , M Werheid ₁ , C Dosche ₁ , M Oezaslan _{1,

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Affiliation

在这项工作中，我们研究了 PVP 和 Ag ⁺离子在多元醇合成中铂纳米立方体 (NC) 形成中的特定作用。采用透射电子显微镜 (TEM)、傅里叶变换红外 (FTIR) 光谱和 X 射线光电子能谱 (XPS) 等各种表征技术来揭示 PVP 和 Ag ⁺离子浓度对所得单分散性和粒径的影响铂 NC。非常有趣的是，我们仅使用 0.4 M PVP（不含 Ag ⁺离子）。此外，Pt NCs 的分散性很大程度上取决于初始 PVP 浓度。这一观察通过控制沿 <100> 方向相对于 <111> 方向的相对增长率，强调了 PVP 在 NC 形成过程中的重要作用。^{时间分辨实验表明，在没有 Ag +}离子的情况下，Pt NCs 的形成和生长比在Ag ⁺的情况下要快得多。离子，这可以通过沿<100>方向的生长速率增强或/和沿<111>的生长速率的抑制来解释。从 XPS 和 FTIR 数据揭示了 PVP 的化学吸附吡咯烷酮环和 Pt 表面之间的电子相互作用，显示出 N 1s 的结合能负移和 Pt-CO 振动带的红移。根据我们的实验结果，我们提出了基于 PVP 作为主要结构导向剂的扩展形成和生长机制。我们的模型表明，形成多层壳的 PVP 脂肪链影响前体离子到初始 Pt 种子的质量传输，以控制具有暴露 {100} 平面的 Pt NCs 的生长速率。总之，我们提供了一个简单的，

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The role of polyvinylpyrrolidone (PVP) as a capping and structure-directing agent in the formation of Pt nanocubes

In this work, we have investigated the specific role of PVP and Ag⁺ ions in the formation of platinum nanocubes (NCs) in polyol synthesis. Various characterization techniques such as transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to unravel the effects of PVP and Ag⁺ ion concentrations on the monodispersity and particle size of the obtained Pt NCs. Very interestingly, we have already fabricated Pt NCs with similar monodispersity and particle size using only 0.4 M PVP (absence of Ag⁺ ions). Furthermore, the dispersity of the Pt NCs strongly depends on the initial PVP concentration. This observation underscores the important role of PVP during the NC formation processes by controlling the relative growth rates along the <100> direction with respect to those of the <111>. Time-resolved experiments show that the formation and growth of Pt NCs are much faster in the absence of Ag⁺ ions than with Ag⁺ ions, which can be explained by the enhanced growth rate along the <100> direction or/and the suppression of the growth rate along the <111>. Electronic interactions between the chemisorbed pyrrolidone ring of the PVP and Pt surface are revealed from the XPS and FTIR data, showing a negative shift of the binding energy of N 1s and a red shift of the Pt–CO vibration band. From our experimental results, we propose extended formation and growth mechanisms based on PVP as the main structure-directing agent. Our model indicates that the aliphatic chains of PVP forming a multi-layer shell influence the mass transport of precursor ions to the initial Pt seed to control the growth rate of Pt NCs with exposed {100} planes. Altogether, we provide a simple, efficient and resource-friendly synthetic guideline for the preparation of nano-sized Pt NCs with high monodispersity and high purity.

更新日期：2019-08-06

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