Abstract

In the framework of the theory of tunneling resonance electron-vibrational spectroscopy, taking into account the interelectron (Coulomb) interaction, which is essential for ultrasmall metal nanoparticles (≤5 nm), a model is constructed that quantitatively explains the results of published spectroscopic experiments carried out using scanning tunneling microscopy, in which for nanoparticles of gold (Au NPs) deposited on pyrolytic graphite, previously there were observed equidistant series of negative differential resistances with periods of 0.1–0.5 V. It was found that series with sufficiently large periods (~0.3–0.5 V), having growing (by the measure of increasing voltage on the nanocontact) envelopes correlate with the sizes of Au NPs and are formed by the Coulomb blockade mechanism. Series with small periods (~0.1 V) correspond to vibrational transitions of atomic particles adsorbed on the surface of Au NPs. A new size effect was discovered for the first time, consisting in the increased adsorption ability of ultrasmall gold nanoparticles having the same sizes (≈3.2 nm) as particles with increased catalytic activity. The new adsorption effect gives a direct and affirmative answer to the frequently discussed question of the “intrinsic” Au NP superactivity, which is not related to the properties of carriers.

中文翻译：

---

超小金颗粒吸附性能的尺寸效应

摘要

在隧穿共振电子振动光谱理论的框架内，考虑到超小金属纳米颗粒（≤5nm）必不可少的电子间（库仑）相互作用，构建了一个模型，该模型定量地解释了已发表的光谱实验的结果使用扫描隧道显微镜进行，其中对于沉积在热解石墨上的金纳米颗粒（Au NPs），以前曾观察到等距的负微分电阻系列，周期为0.1-0.5V。发现该系列的周期足够大（约0.3-0.5 V）的包络层（通过测量纳米触点上的电压增加）与Au NP的尺寸相关，并且是通过库仑阻塞机制形成的。小周期系列（〜0。1 V）对应于吸附在Au NPs表面的原子粒子的振动跃迁。首次发现了新的尺寸效应，包括与具有增加的催化活性的颗粒具有相同尺寸（≈3.2nm）的超小金纳米颗粒的吸附能力增强。新的吸附作用直接回答了“内在” Au NP超级活性这一经常讨论的问题，该问题与载体的性质无关。