Chen Peng-Cheng, Gao Mengyu, McCandler Caitlin A, Song Chengyu, Jin Jianbo, Yang Yao, Maulana Arifin Luthfi, Persson Kristin A, Yang Peidong
Kavli Energy Nanoscience Institute, University of California, Berkeley, CA, USA.
Department of Chemistry, University of California, Berkeley, CA, USA.
Nat Nanotechnol. 2024 Jun;19(6):775-781. doi: 10.1038/s41565-024-01626-0. Epub 2024 Mar 1.
Understanding the mixing behaviour of elements in a multielement material is important to control its structure and property. When the size of a multielement material is decreased to the nanoscale, the miscibility of elements in the nanomaterial often changes from its bulk counterpart. However, there is a lack of comprehensive and quantitative experimental insight into this process. Here we explored how the miscibility of Au and Rh evolves in nanoparticles of sizes varying from 4 to 1 nm and composition changing from 15% Au to 85% Au. We found that the two immiscible elements exhibit a phase-separation-to-alloy transition in nanoparticles with decreased size and become completely miscible in sub-2 nm particles across the entire compositional range. Quantitative electron microscopy analysis and theoretical calculations were used to show that the observed immiscibility-to-miscibility transition is dictated by particle size, composition and possible surface adsorbates present under the synthesis conditions.
了解多元素材料中元素的混合行为对于控制其结构和性能至关重要。当多元素材料的尺寸减小到纳米尺度时，纳米材料中元素的混溶性通常与其体相材料不同。然而，目前缺乏对这一过程全面且定量的实验认识。在此，我们探究了金（Au）和铑（Rh）在尺寸从4纳米变化到1纳米、组成从15% Au到85% Au的纳米颗粒中的混溶性是如何演变的。我们发现，这两种不混溶的元素在尺寸减小的纳米颗粒中呈现出从相分离到合金化的转变，并且在整个组成范围内，在尺寸小于2纳米的颗粒中完全混溶。定量电子显微镜分析和理论计算表明，观察到的从不混溶到混溶的转变是由颗粒尺寸、组成以及合成条件下可能存在的表面吸附物决定的。
