Ye Zhongju, Wei Lin, Xiao Lehui, Wang Jianfang
State Key Laboratory of Medicinal Chemical Biology , Tianjin Key Laboratory of Biosensing and Molecular Recognition , College of Chemistry , Nankai University , Tianjin , 300071 , China . Email:
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research , Key Laboratory of Phytochemical R&D of Hunan Province , College of Chemistry and Chemical Engineering , Hunan Normal University , Changsha , 410082 , China.
Chem Sci. 2019 Apr 29;10(22):5793-5800. doi: 10.1039/c9sc01666j. eCollection 2019 Jun 14.
Understanding morphology dependent catalytic kinetics from a single nanoparticle plays a significant role in the development of robust nano-catalysts with high efficiency. Unfortunately, detailed knowledge of the morphology dependent catalytic properties of single nanoparticles after shape transitions is lacking. In this work, the distinct catalytic properties of a single gold nanoparticle (GNP) after symmetry breaking were disclosed at the single-particle level for the first time. The morphology of the spherical GNP was elongated into a rod shape (, gold nanorod, GNR) with a tightly focused Gaussian laser beam based on the photothermal effect. By using the fluorogenic oxidation reaction (, amplex red to resorufin) as a model reaction, noticeable variation in catalytic efficiency after the shape modulation process was found at the single-particle level. The GNP displays noticeably higher catalytic efficiency which might be ascribed to the heterogeneous lattice structure on the particle surface as confirmed by transmission electron microscopy (TEM) characterization. Rearrangement of surface atoms after shape modulation normally generates a more ordered crystal structure, resulting in a lower surface energy for catalytic reaction. However, both of these nanoparticles still exhibit dynamic activity fluctuation in a temporal dependent route, indicating a distinct spontaneous dynamic surface restructuring process. These kinetic evidences might facilitate the development nanoparticle-based heterogeneous catalysts, particularly based on the morphology effect.
从单个纳米颗粒理解形态依赖的催化动力学在开发高效的稳健纳米催化剂方面起着重要作用。不幸的是，缺乏关于形状转变后单个纳米颗粒的形态依赖催化特性的详细知识。在这项工作中，首次在单颗粒水平上揭示了单个金纳米颗粒（GNP）在对称性破坏后的独特催化特性。基于光热效应，利用紧密聚焦的高斯激光束将球形GNP的形态拉长为棒状（即金纳米棒，GNR）。通过使用荧光氧化反应（即从吖啶红到试卤灵）作为模型反应，在单颗粒水平上发现了形状调制过程后催化效率的显著变化。GNP显示出明显更高的催化效率，这可能归因于通过透射电子显微镜（TEM）表征所证实的颗粒表面的异质晶格结构。形状调制后表面原子的重排通常会产生更有序的晶体结构，从而导致催化反应的表面能降低。然而，这两种纳米颗粒在时间依赖路径上仍表现出动态活性波动，表明存在明显的自发动态表面重构过程。这些动力学证据可能有助于基于纳米颗粒的多相催化剂的开发，特别是基于形态效应的催化剂。
