Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
J Am Chem Soc. 2021 Oct 27;143(42):17535-17547. doi: 10.1021/jacs.1c07217. Epub 2021 Oct 13.
Although the tailored metal active sites and porous architectures of MOFs hold great promise for engineering challenges ranging from gas separations to catalysis, a lack of understanding of how to improve their stability limits their use in practice. To overcome this limitation, we extract thousands of published reports of the key aspects of MOF stability necessary for their practical application: the ability to withstand high temperatures without degrading and the capacity to be activated by removal of solvent molecules. From nearly 4000 manuscripts, we use natural language processing and image analysis to obtain over 2000 solvent-removal stability measures and 3000 thermal degradation temperatures. We analyze the relationships between stability properties and the chemical and geometric structures in this set to identify limits of prior heuristics derived from smaller sets of MOFs. By training predictive machine learning (ML, i.e., Gaussian process and artificial neural network) models to encode the structure-property relationships with graph- and pore-structure-based representations, we are able to make predictions of stability orders of magnitude faster than conventional physics-based modeling or experiment. Interpretation of important features in ML models provides insights that we use to identify strategies to engineer increased stability into typically unstable 3d-transition-metal-containing MOFs that are frequently targeted for catalytic applications. We expect our approach to accelerate the time to discovery of stable, practical MOF materials for a wide range of applications.
尽管 MOF 的定制金属活性位点和多孔架构在气体分离到催化等工程挑战中具有很大的应用前景,但由于缺乏对如何提高其稳定性的理解,限制了它们在实际中的应用。为了克服这一限制,我们提取了数千篇关于 MOF 稳定性的关键方面的已发表报告,这些方面对于其实际应用是必要的:在不降解的情况下承受高温的能力,以及通过去除溶剂分子进行激活的能力。从近 4000 篇手稿中,我们使用自然语言处理和图像分析获得了超过 2000 种溶剂去除稳定性测量值和 3000 种热降解温度。我们分析了这组稳定性性质与化学和几何结构之间的关系,以确定从较小 MOF 集推导出来的先前启发式的限制。通过训练预测性机器学习 (ML,即高斯过程和人工神经网络) 模型,以基于图和孔结构的表示来编码结构-性质关系,我们能够比传统基于物理的建模或实验更快地进行稳定性顺序的预测。对 ML 模型中的重要特征的解释提供了我们用于识别策略的见解,这些策略可用于将通常不稳定的 3d 过渡金属含 MOF 工程化,以提高稳定性,这些 MOF 通常是催化应用的目标。我们预计,我们的方法将加快发现稳定、实用的 MOF 材料的时间,适用于广泛的应用。