This article aims to address the formation and the structural disordering/ordering phenomena of PtNi nanoalloys supported on hollow graphitic spheres (HGSs) using pair distribution function (PDF) analysis under ex situ/in situ data collection conditions. Starting from small nanoparticles (10–15 Å in diameter) embedded in HGSs, structural changes were monitored during stepwise heating and cooling of the sample using in situ PDF analysis. In order to evaluate the conventional synthesis route for the production of PtNi nanoalloys supported on HGSs, ex situ PDF experiments were performed before and after heat treatment in a furnace. The studies demonstrate that the local structure of the in situ synthesised PtNi nanoalloy differs from its ex situ synthesised counterpart. A partially ordered PtNi nanoalloy was obtained during the stepwise in situ cooling of the precursor, whereas the conventional ex situ synthesis route did not lead to the formation of an ordered crystal structure. In this study we could show that rapid heating and cooling results in a disordered PtNi alloy whereas slow heating and cooling leads to disorder–order transitions in PtNi.

中文翻译：

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使用原位对分布函数分析监测空心石墨球上负载的PtNi纳米合金的形成†

本文旨在解决形成和使用下对分布函数（PDF）分析支撑在中空石墨球PtNi纳米合金的结构无序化/排序现象（HGSS）易地/原位数据收集条件。从嵌入在HGS中的小纳米颗粒（直径10–15Å）开始，使用原位PDF分析在逐步加热和冷却样品的过程中监测结构变化。为了评估在HGS上制备PtNi纳米合金的常规合成路线，在炉内热处理前后进行了非原位PDF实验。研究表明，原位的局部结构合成PtNi纳米合金不同于其易地合成对应物。在前驱物的逐步原位冷却过程中获得了部分有序的PtNi纳米合金，而常规的非原位合成路线并未导致形成有序的晶体结构。在这项研究中，我们可以证明快速加热和冷却会导致无序的PtNi合金，而缓慢加热和冷却会导致PtNi的无序有序转变。