Vega Lorena, Viñes Francesc, Neyman Konstantin M
Departament de Ciència de Materials i Química Física, Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
Nanomaterials (Basel). 2021 Dec 22;12(1):17. doi: 10.3390/nano12010017.
Metal nanoparticles (NPs) are ubiquitous in many fields, from nanotechnology to heterogeneous catalysis, with properties differing from those of single-crystal surfaces and bulks. A key aspect is the size-dependent evolution of NP properties toward the bulk limit, including the adoption of different NP shapes, which may bias the NP stability based on the NP size. Herein, the stability of different Pd NPs ( = 10-1504 atoms) considering a myriad of shapes is investigated by first-principles energy optimisation, leading to the determination that icosahedron shapes are the most stable up to a size of ca. 4 nm. In NPs larger than that size, truncated octahedron shapes become more stable, yet a presence of larger {001} facets than the Wulff construction is forecasted due to their increased stability, compared with (001) single-crystal surfaces, and the lower stability of {111} facets, compared with (111) single-crystal surfaces. The NP cohesive energy breakdown in terms of coordination numbers is found to be an excellent quantitative tool of the stability assessment, with mean absolute errors of solely 0.01 eV·atom, while a geometry breakdown allows only for a qualitative stability screening.
金属纳米颗粒（NPs）在从纳米技术到多相催化等许多领域都普遍存在，其性质与单晶表面和块体不同。一个关键方面是纳米颗粒性质随尺寸向块体极限的演变，包括采用不同的纳米颗粒形状，这可能会根据纳米颗粒的尺寸影响其稳定性。在此，通过第一性原理能量优化研究了考虑多种形状的不同钯纳米颗粒（含10 - 1504个原子）的稳定性，结果确定在尺寸约为4纳米以下时，二十面体形状最稳定。在大于该尺寸的纳米颗粒中，截顶八面体形状变得更稳定，但预计会出现比伍尔夫结构更大的{001}面，这是因为与（001）单晶表面相比，它们的稳定性增加，且与（111）单晶表面相比，{111}面的稳定性较低。发现基于配位数的纳米颗粒内聚能分解是稳定性评估的一种出色定量工具，平均绝对误差仅为0.01 eV·原子，而几何分解仅允许进行定性的稳定性筛选。
