Bechelli Solene, Gonzalez B, Piquet Vincent, Essafri Ilham, Desgranges Caroline, Delhommelle Jerome
Department of Chemistry, University of North Dakota , Grand Forks, North Dakota 58202, United States.
J Phys Chem B. 2017 Sep 14;121(36):8558-8563. doi: 10.1021/acs.jpcb.7b06028. Epub 2017 Aug 29.
Using molecular simulation, we shed light on the crystal nucleation process in systems of Cu, Ni, and their nanoalloy. For each system, we simulate the formation of the crystal nucleus along the entire nucleation pathway and determine the free energy barrier overcome by the system to form a critical nucleus. Comparing the results obtained for the pure metals to those for the nanoalloy, we analyze the impact of alloying on the free energy of nucleation, as well as on the size and structure of the crystal nucleus. Specifically, we relate the greater free energy of nucleation, and bigger critical nuclei, obtained for the nanoalloy, to the difference in size and cohesive energy between the two metals. Furthermore, we characterize the dependence of the local composition of the incipient crystal cluster on its size, which is of key significance for the applications of bimetallic nanoparticles in catalysis.
通过分子模拟，我们揭示了铜、镍及其纳米合金体系中的晶体成核过程。对于每个体系，我们沿着整个成核路径模拟晶核的形成，并确定体系形成临界核时所克服的自由能垒。将纯金属与纳米合金的结果进行比较，我们分析了合金化对成核能以及晶核尺寸和结构的影响。具体而言，我们将纳米合金获得的更高成核能和更大临界核与两种金属之间的尺寸和内聚能差异联系起来。此外，我们还表征了初始晶体簇的局部组成对其尺寸的依赖性，这对于双金属纳米颗粒在催化中的应用具有关键意义。
