Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Nano Lett. 2023 Jun 28;23(12):5437-5444. doi: 10.1021/acs.nanolett.3c00250. Epub 2023 Jun 16.
Analysis of the influence of dissimilar facets on the adsorption, stability, mobility, and reactivity of surface ligands is essential for designing ligand-coated nanocrystals with optimal functionality. Herein, para-nitrothiophenol and nitronaphthalene were chemisorbed and physisorbed, respectively, on Au nanocrystals, and the influence of different facets within a single Au nanocrystal on ligands properties were identified by IR nanospectroscopy measurements. Preferred adsorption was probed on (001) facets for both ligands, with a lower density on (111) facets. Exposure to reducing conditions led to nitro reduction and diffusion of both ligands toward the top (111) facet. Nitrothiophenol was characterized with a diffusivity higher than that of nitronaphthalene. Moreover, the strong thiol-Au interaction led to the diffusion of Au atoms and the formation of thiol-coated Au nanoparticles on the silicon surface. It is identified that the adsorption and reactivity of surface ligands were mainly influenced by the atomic properties of each facet, while diffusion was controlled by ligand-metal interactions.
分析不同晶面对于表面配体吸附、稳定性、迁移性和反应性的影响，对于设计具有最佳功能的配体包覆纳米晶体至关重要。在此，对金纳米晶体进行了对硝基苯硫酚的化学吸附和硝萘的物理吸附，并通过红外纳米光谱测量确定了单个金纳米晶体内部不同晶面对配体性质的影响。对于两种配体，均优先在（001）晶面上吸附，而在（111）晶面上的吸附密度较低。在还原条件下，会导致硝基还原，并且两种配体都会向顶（111）晶面迁移。对硝基苯硫酚的扩散系数要高于硝萘。此外，强的巯基-金相互作用导致金原子的扩散，并在硅表面形成巯基包覆的金纳米颗粒。可以确定，表面配体的吸附和反应性主要受每个晶面的原子性质影响，而扩散则由配体-金属相互作用控制。
