Owen Cameron J, Xie Yu, Johansson Anders, Sun Lixin, Kozinsky Boris
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Nat Commun. 2024 May 6;15(1):3790. doi: 10.1038/s41467-024-48192-6.
Metal surfaces have long been known to reconstruct, significantly influencing their structural and catalytic properties. Many key mechanistic aspects of these subtle transformations remain poorly understood due to limitations of previous simulation approaches. Using active learning of Bayesian machine-learned force fields trained from ab initio calculations, we enable large-scale molecular dynamics simulations to describe the thermodynamics and time evolution of the low-index mesoscopic surface reconstructions of Au (e.g., the Au(111)-'Herringbone,' Au(110)-(1 × 2)-'Missing-Row,' and Au(100)-'Quasi-Hexagonal' reconstructions). This capability yields direct atomistic understanding of the dynamic emergence of these surface states from their initial facets, providing previously inaccessible information such as nucleation kinetics and a complete mechanistic interpretation of reconstruction under the effects of strain and local deviations from the original stoichiometry. We successfully reproduce previous experimental observations of reconstructions on pristine surfaces and provide quantitative predictions of the emergence of spinodal decomposition and localized reconstruction in response to strain at non-ideal stoichiometries. A unified mechanistic explanation is presented of the kinetic and thermodynamic factors driving surface reconstruction. Furthermore, we study surface reconstructions on Au nanoparticles, where characteristic (111) and (100) reconstructions spontaneously appear on a variety of high-symmetry particle morphologies.
长期以来，人们都知道金属表面会发生重构，这对其结构和催化性能有显著影响。由于先前模拟方法的局限性，这些微妙转变的许多关键机理方面仍知之甚少。通过从第一性原理计算中训练贝叶斯机器学习力场的主动学习方法，我们能够进行大规模分子动力学模拟，以描述金的低指数介观表面重构的热力学和时间演化（例如，Au(111)-“人字形”、Au(110)-(1×2)-“缺失行”和Au(100)-“准六边形”重构）。这种能力使我们能够从原子层面直接理解这些表面状态从其初始晶面动态出现的过程，提供了以前无法获得的信息，如成核动力学以及在应变和与原始化学计量比的局部偏差影响下重构的完整机理解释。我们成功地重现了先前在原始表面上重构的实验观察结果，并提供了在非理想化学计量比下响应应变时旋节分解和局部重构出现的定量预测。本文提出了驱动表面重构的动力学和热力学因素的统一机理解释。此外，我们研究了金纳米颗粒上的表面重构，其中特征性的(111)和(100)重构会在各种高对称颗粒形态上自发出现。
