Rise of atomically dispersed metal catalysts: Are they a new class of catalysts?

Atomically dispersed metal catalysts or single-atom catalysts have made great strides during the past decade in the catalysis field. While an initial vision of atomically dispersed metal catalysts was to combine the advantages of homogeneous and heterogeneous catalysts, their unexpected potentials continue to be discovered. In this account, we introduce historical backgrounds underpinning the emergence of atomically dispersed metal catalysts. Next, we illustrate some recent examples demonstrating the unusual reactivities of atomically dispersed metal catalysts, which are hard to realize by homogeneous or heterogeneous catalysts. We conclude the account by suggesting the remaining challenges in this exciting field.