Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland.
Chem Rev. 2020 Nov 11;120(21):11703-11809. doi: 10.1021/acs.chemrev.0c00576. Epub 2020 Oct 21.
Isolated atoms featuring unique reactivity are at the heart of enzymatic and homogeneous catalysts. In contrast, although the concept has long existed, single-atom heterogeneous catalysts (SACs) have only recently gained prominence. Host materials have similar functions to ligands in homogeneous catalysts, determining the stability, local environment, and electronic properties of isolated atoms and thus providing a platform for tailoring heterogeneous catalysts for targeted applications. Within just a decade, we have witnessed many examples of SACs both disrupting diverse fields of heterogeneous catalysis with their distinctive reactivity and substantially enriching our understanding of molecular processes on surfaces. To date, the term SAC mostly refers to late transition metal-based systems, but numerous examples exist in which isolated atoms of other elements play key catalytic roles. This review provides a compositional encyclopedia of SACs, celebrating the 10th anniversary of the introduction of this term. By defining single-atom catalysis in the broadest sense, we explore the full elemental diversity, joining different areas across the whole periodic table, and discussing historical milestones and recent developments. In particular, we examine the coordination structures and associated properties accessed through distinct single-atom-host combinations and relate them to their main applications in thermo-, electro-, and photocatalysis, revealing trends in element-specific evolution, host design, and uses. Finally, we highlight frontiers in the field, including multimetallic SACs, atom proximity control, and possible applications for multistep and cascade reactions, identifying challenges, and propose directions for future development in this flourishing field.
具有独特反应性的孤立原子是酶和均相催化剂的核心。相比之下，尽管这一概念由来已久，但单原子多相催化剂（SAC）直到最近才受到关注。主体材料具有与均相催化剂配体相似的功能，决定了孤立原子的稳定性、局部环境和电子性质，从而为定制针对特定应用的多相催化剂提供了一个平台。在短短十年内，我们已经看到了许多 SAC 的例子，它们以其独特的反应性打破了多相催化的多个领域的格局，并极大地丰富了我们对表面分子过程的理解。迄今为止，SAC 一词主要指的是后过渡金属基体系，但也有许多例子表明，其他元素的孤立原子在关键催化作用中发挥了作用。这篇综述提供了 SAC 的组成百科全书，庆祝这一术语提出 10 周年。通过最广泛的意义定义单原子催化，我们探索了完全的元素多样性，加入了整个元素周期表的不同领域，并讨论了历史里程碑和最新发展。特别是，我们研究了通过不同的单原子-主体组合获得的配位结构和相关性质，并将其与它们在热、电和光催化中的主要应用联系起来，揭示了特定元素的演变、主体设计和用途的趋势。最后，我们强调了该领域的前沿，包括多金属 SAC、原子邻近控制以及多步和级联反应的可能应用，确定了挑战，并为这一蓬勃发展的领域提出了未来发展的方向。
