Abstract Platinum nanostructures are of large interest because of their electrocatalytic properties, enhanced by the high surface/to volume ratio, and find applications in numerous fields from fuel cells and electrolyzers, to gas biosensors and nano-biomedicine. In this work we present a simple procedure, based on spontaneous galvanic displacement, to obtain Pt nanoparticles (PtNPs) directly on Si substrate. The nucleation and growth processes involved in the deposition have been studied by Transmission Electron Microscopy and Rutherford Backscattering Spectrometry. The nucleation is quite complex and includes, first, the generation of primary non-growing clusters, with size smaller than 2 nm. Then, for longer deposition times, larger particles are formed, resulting from dynamic coalescence of primary clusters with/or single ion attachment processes. The growth of such larger particles follows the prediction of the classical diffusion limited model. Moreover, the large nanoparticles are poly-crystalline and exhibit a nano-porous structure, in agreement with a mixed aggregative-diffusion limited growth. The nano-porous structure implies a high internal surface area, therefore making these particles particularly promising as efficient catalysts.

中文翻译：

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对电流置换沉积过程中硅表面 Pt 成核机制的新见解

摘要 铂纳米结构因其电催化性能而备受关注，并因高表面积/体积比而增强，并在燃料电池和电解槽、气体生物传感器和纳米生物医学等众多领域中得到应用。在这项工作中，我们提出了一个基于自发电流位移的简单程序，以直接在 Si 衬底上获得 Pt 纳米粒子 (PtNPs)。通过透射电子显微镜和卢瑟福背散射光谱法研究了沉积中涉及的成核和生长过程。成核非常复杂，首先包括生成尺寸小于 2 nm 的初级非生长簇。然后，对于更长的沉积时间，形成更大的颗粒，由具有/或单离子附着过程的初级簇的动态聚结产生。这种较大颗粒的生长遵循经典扩散限制模型的预测。此外，大纳米粒子是多晶的，并表现出纳米多孔结构，与混合聚集扩散限制生长一致。纳米多孔结构意味着高内表面积，因此使这些颗粒特别有希望作为有效的催化剂。