Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China.
Center for Integrated Spectroscopy, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China.
Nat Commun. 2023 May 22;14(1):2934. doi: 10.1038/s41467-023-38536-z.
Deciphering the three-dimensional atomic structure of solid-solid interfaces in core-shell nanomaterials is the key to understand their catalytical, optical and electronic properties. Here, we probe the three-dimensional atomic structures of palladium-platinum core-shell nanoparticles at the single-atom level using atomic resolution electron tomography. We quantify the rich structural variety of core-shell nanoparticles with heteroepitaxy in 3D at atomic resolution. Instead of forming an atomically-sharp boundary, the core-shell interface is found to be atomically diffuse with an average thickness of 4.2 Å, irrespective of the particle's morphology or crystallographic texture. The high concentration of Pd in the diffusive interface is highly related to the free Pd atoms dissolved from the Pd seeds, which is confirmed by atomic images of Pd and Pt single atoms and sub-nanometer clusters using cryogenic electron microscopy. These results advance our understanding of core-shell structures at the fundamental level, providing potential strategies into precise nanomaterial manipulation and chemical property regulation.
解析核壳纳米材料中固-固界面的三维原子结构是理解其催化、光学和电子性质的关键。在这里，我们使用原子分辨电子断层扫描技术在单原子水平上探测钯-铂核壳纳米颗粒的三维原子结构。我们以原子分辨率量化了具有异质外延的核壳纳米颗粒在三维空间中的丰富结构多样性。核壳界面并不是形成原子级锐利的边界，而是原子扩散的，平均厚度为 4.2Å，与颗粒的形态或晶体织构无关。扩散界面中高浓度的 Pd 与从 Pd 种子中溶解的游离 Pd 原子高度相关，这一点通过使用低温电子显微镜获得的 Pd 和 Pt 单原子和亚纳米团簇的原子图像得到了证实。这些结果在基础层面上推进了我们对核壳结构的理解，为精确的纳米材料操纵和化学性质调控提供了潜在策略。
