Wy Younghyun, Jung Hayoon, Hong Jong Wook, Han Sang Woo
Center for Nanotectonics, Department of Chemistry and KI for the NanoCentury, KAIST, Daejeon 34141, Korea.
Department of Chemistry, University of Ulsan, Ulsan 44610, Korea.
Acc Chem Res. 2022 Mar 15;55(6):831-843. doi: 10.1021/acs.accounts.1c00682. Epub 2022 Feb 25.
ConspectusLocalized surface plasmon resonance is a unique property appearing in certain metal nanostructures, which can generate hot carriers (electrons and holes) and bring about an intense electromagnetic field localized near the surface of nanostructures. Specific locations, such as the rough surfaces and gaps in nanostructures, where a strong electromagnetic field is formed are referred to as hot spots. Hot-spot-containing plasmonic nanostructures have shown great promise in molecular sensing and plasmon-induced catalytic applications by exploiting the unique optical properties of hot spots. In this Account, we will review our recent developments in the synthesis of Au nanostructures consisting of multiple hot spots and Au-based heteronanostructures combining secondary active metals or semiconductors with Au nanostructures as promising plasmonic platforms for hot-spot-induced sensing and photocatalysis. We first provide a brief introduction to Au nanocrystals and Au nanoparticle assemblies with multiple hot spots. High-index-faceted hexoctahedral Au nanocrystals having multiple high-curvature vertices and edges are beneficial for the generation of an intense and reproducible electromagnetic field, which can enhance the performance of surface-enhanced Raman scattering-based molecular sensing. In addition, the engineering of interparticle gaps in Au nanoparticle assemblies to have a controlled size and a certain number of gaps can lead to the enhancement of plasmonic properties due to the significant amplification of the electromagnetic field at interparticle gaps. We then discuss hot-spot-containing Au-based heteronanostructures prepared by growing secondary components on the aforementioned Au nanostructures. With a combination of merit from strong plasmon energy formed by hot spots and catalytically active secondary materials, Au-based heteronanostructures have emerged as an attractive and versatile catalyst platform for various photocatalytic reactions. Through the control of key factors governing the photocatalysis of Au-based heteronanostructures, such as the coupling manner, shell thickness of secondary materials, and intimacy of contact, the plasmon energy formation of heteronanostructures and its transfer to catalytically active materials can be optimized, leading to the promotion of photocatalysis, such as photocatalytic hydrogen evolution. The rational design of Au nanostructures and Au-based heteronanostructures with multiple hot spots not only could realize enhanced sensing and photocatalysis but also could enable the understanding of the geometry-performance relationship. It is envisioned that the developed strategies can offer new opportunities for the design of various high-efficiency catalytic platforms.
综述
局域表面等离子体共振是某些金属纳米结构中出现的一种独特性质，它能够产生热载流子（电子和空穴）并在纳米结构表面附近产生强烈的局域电磁场。纳米结构中的粗糙表面和间隙等特定位置会形成强电磁场，这些位置被称为热点。含热点的等离子体纳米结构通过利用热点独特的光学性质，在分子传感和等离子体诱导催化应用中展现出巨大潜力。在本综述中，我们将回顾我们在合成由多个热点组成的金纳米结构以及将二次活性金属或半导体与金纳米结构相结合的金基异质纳米结构方面的最新进展，这些结构是用于热点诱导传感和光催化的有前景的等离子体平台。我们首先简要介绍具有多个热点的金纳米晶体和金纳米颗粒组装体。具有多个高曲率顶点和边缘的高指数面八面体金纳米晶体有利于产生强烈且可重复的电磁场，这可以提高基于表面增强拉曼散射的分子传感性能。此外，对金纳米颗粒组装体中的颗粒间间隙进行工程设计，使其具有可控的尺寸和一定数量的间隙，由于颗粒间间隙处电磁场的显著放大，可导致等离子体性质的增强。然后我们讨论通过在上述金纳米结构上生长二次组分制备的含热点的金基异质纳米结构。结合热点形成的强等离子体能量和催化活性二次材料的优点，金基异质纳米结构已成为用于各种光催化反应的有吸引力且通用的催化剂平台。通过控制影响金基异质纳米结构光催化的关键因素，如耦合方式、二次材料的壳层厚度和接触紧密程度，可以优化异质纳米结构的等离子体能量形成及其向催化活性材料的转移，从而促进光催化，如光催化析氢。合理设计具有多个热点的金纳米结构和金基异质纳米结构不仅可以实现增强的传感和光催化，还可以深入理解几何结构与性能的关系。可以预见，所开发的策略可为设计各种高效催化平台提供新的机会。
