Zhang Tianjun, Walsh Andrew G, Yu Jihong, Zhang Peng
Department of Chemistry, Dalhousie University, 6274 Coburg Road, B3H 4R2, Halifax, Canada.
Chem Soc Rev. 2021 Jan 7;50(1):569-588. doi: 10.1039/d0cs00844c. Epub 2020 Nov 10.
Monometallic catalysts, in particular those containing noble metals, are frequently used in heterogeneous catalysis, but they are expensive, rare and the ability to tailor their structures and properties remains limited. Traditionally, alloy catalysts have been used instead that feature enhanced electronic and chemical properties at a reduced cost. Furthermore, the introduction of single metal atoms anchored onto supports provided another effective strategy to increase both the atomic efficiency and the chance of tailoring the properties. Most recently, single-atom alloy catalysts have been developed in which one metal is atomically dispersed throughout the catalyst via alloy bonding; such catalysts combine the traditional advantages of alloy catalysts with the new feature of tailoring properties achievable with single atom catalysts. This review will first outline the atomic scale structural analysis on single-atom alloys using microscopy and spectroscopy tools, such as high-angle annular dark field imaging-scanning transmission electron microscopy and extended X-ray absorption fine structure spectroscopy. Next, progress in research to understand the electronic properties of single-atom alloys using X-ray spectroscopy techniques and quantum calculations will be presented. The catalytic activities of single-atom alloys in a few representative reactions will be further discussed to demonstrate their structure-property relationships. Finally, future perspectives for single-atom alloy catalysts from the structural, electronic and reactivity aspects will be proposed.
单金属催化剂，特别是那些含有贵金属的催化剂，常用于多相催化，但它们价格昂贵、稀有，且调整其结构和性能的能力仍然有限。传统上，人们转而使用具有增强电子和化学性质且成本降低的合金催化剂。此外，将单金属原子锚定在载体上提供了另一种提高原子效率和调整性能机会的有效策略。最近，已开发出单原子合金催化剂，其中一种金属通过合金键合原子分散在整个催化剂中；这类催化剂将合金催化剂的传统优势与单原子催化剂可实现的性能调整新特性结合起来。本综述将首先概述使用显微镜和光谱工具（如高角度环形暗场成像-扫描透射电子显微镜和扩展X射线吸收精细结构光谱）对单原子合金进行的原子尺度结构分析。接下来，将介绍利用X射线光谱技术和量子计算来理解单原子合金电子性质的研究进展。将进一步讨论单原子合金在一些代表性反应中的催化活性，以展示它们的结构-性能关系。最后，将从结构、电子和反应性方面提出单原子合金催化剂的未来展望。
