Polyethylenimine (PEI)-capped gold nanoparticles have found a wide use in the sensing, catalytic, and biomedical fields. However, a controlled synthesis of well-defined polyhedral PEI-capped gold nanoparticles is yet to be explored. In this work, we have demonstrated that, through a seeded growth, well-defined polyhedral PEI-capped nanoparticles of gold (38–50 nm) can be synthesized. The numerous sharp tips and edges facilitated their use as both active surface-enhanced Raman scattering (SERS) and catalytic materials. Using the conversion of 4-nitrothiophenol to 4-aminothiophenol as a model reaction, the SERS and catalytic properties of the polyhedral PEI-capped nanoparticles were simultaneously demonstrated. The polyhedral gold nanoparticles, thus, serve as a simple but active bifunctional substrate for in situ SERS-based chemical reaction monitoring. In addition, the easy fabrication of these bifunctional nanoparticles makes them stand out from the numerous conventional substrates that require a multistep and complex process of integrating catalytic and SERS properties into a single nanomaterial.

聚乙烯亚胺（PEI）包覆的金纳米颗粒已在传感，催化和生物医学领域得到了广泛的应用。然而，明确定义的多面体PEI封端的金纳米粒子的受控合成尚待探索。在这项工作中，我们已经证明，通过种子生长，可以合成定义明确的多面体PEI封端的金纳米颗粒（38–50 nm）。大量尖锐的尖端和边缘有助于将其用作活性表面增强拉曼散射（SERS）和催化材料。使用4-硝基硫代苯酚向4-氨基硫代苯酚的转化作为模型反应，同时证明了多面体PEI封端的纳米粒子的SERS和催化性能。因此，多面体金纳米颗粒 用作简单但有效的双功能底物，用于基于SERS的原位化学反应监测。另外，这些双功能纳米粒子的易于制造使其在众多常规基材中脱颖而出，这些基材需要将催化和SERS特性整合到单个纳米材料中的多步骤且复杂的过程。