海归学者发起的公益学术平台
分享信息，整合资源
交流学术，偶尔风月
异相催化对于可持续能源产生和存储、精细化学品的合成和食品生产都有重要影响。更好的催化剂的发现需要从原子尺度来加速结构-性能关系的认识。计算能力和资源的迅速发展，使利用密度泛函理论来分析复杂反应化学过程成为可能，例如，多配位基吸附物和高吸附物覆盖度。然而，要模拟这些复杂的反应化学仍然存在很大挑战，例如，在低对称性表面的高吸附物覆盖度的分析，以及缺乏普适的流程来系统地模拟这些情况。这些问题急需一个有效工具，能够在众多不同几何构型中探测唯一吸附物构型，并且利用这些信息能够推演更高覆盖度的构型。
来自美国普度大学的Greeley教授研究团队，报道了一种基于Python的算法，利用非直接图形表示来描述给定的异相催化模型系统。这些图形表示是多分子的，涉及到多种不同类型的原子和价键，以及吸附物原子和基底表面之间的多种接触点（单、双和三配位基）。这些图形表示用来探测唯一的吸附物构型和催化剂表面的吸附位点。而且，这些图形表示还可以确定和比较低或高覆盖度唯一构型以及单配位基和多配位基几何构型。这一方法模拟进一步与进化算法相结合，能够系统地估计低对称性表面上的高覆盖度模型。另外，最近邻相互作用的估计等设计原则可以用来简化大量样品空间。作者利用这一策略演示了Pt3Sn(111)梯田表面吸附NO的覆盖度依赖相图分析和反应中间物丙炔(CHCCH3*)吸附在PtIn(021)台阶表面时吸附能与唯一最小能构型的确定。这种基于图形的方法在异相催化领域构建了一种新的图形理论，能够自动、快速地筛选与吸附物相互作用的多种表面接触点组合，而且可以拓展到多种原子模型应用。该文近期发表于npj Computational Materials 6: 79 (2020)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。
Graph theory approach to determine configurationsof multidentate and high coverage adsorbatesfor heterogeneous catalysis
Siddharth Deshpande, Tristan Maxson& Jeffrey Greeley
Heterogeneous catalysts constitute a crucial component of many industrial processes, and to gain an understanding of the atomicscale features of such catalysts, ab initio density functional theory is widely employed. Recently, growing computational power haspermitted the extension of such studies to complex reaction networks involving either high adsorbate coverages or multidentateadsorbates, which bind to the surface through multiple atoms. Describing all possible adsorbate configurations for such systems,however, is often not possible based on chemical intuition alone. To systematically treat such complexities, we present ageneralized Python-based graph theory approach to convert atomic scale models into undirected graph representations. Theserepresentations, when combined with workflows such as evolutionary algorithms, can systematically generate high coverageadsorbate models and classify unique minimum energy multidentate adsorbate configurations for surfaces of low symmetry,including multi-elemental alloy surfaces, steps, and kinks. Two case studies are presented which demonstrate these capabilities;first, an analysis of a coverage-dependent phase diagram of absorbate NO on the Pt3Sn(111) terrace surface, and second, aninvestigation of adsorption energies, together with identifying unique minimum energy configurations, for the reactionintermediate propyne (CHCCH3*) adsorbed on a PdIn(021) step surface. The evolutionary algorithm approach reproduces highcoverage configurations of NO on Pt3Sn(111) using only 15% of the number of simulations required for a brute force approach.Furthermore, the screening of potentially hundreds of multidentate adsorbates is shown to be possible without humanintervention. The strategy presented is quite general and can be applied to a spectrum of complex atomic systems.
本文系网易新闻·网易号“各有态度”特色内容
媒体转载联系授权请看下方