ABSTRACT
Atomically dispersed metallic materials or single-atom catalysts (SACs) have become promising candidates in contemporary catalysis science because of their merits in terms of highly efficient use of metal atoms, precisely identified active sites, high activity, and controllable selectivity. However, for practical large-scale applications of SACs to become possible, advances are still needed to overcome stability and clustering problems. To date, numerous experimental and theoretical investigations have studied the stability and performance of SACs on different substrates. In this chapter, we provide a systematic overview of the recent research progress for SACs on different substrates from the theoretical side. The stability of the single metal atom is analyzed based on its two main determining factors, namely the formation energies and diffusion energy barriers. In addition, the unique electronic properties of the single atoms are analyzed and related to the d-band center theory. We review in detail several representative reactions on different substrates ranging from metal oxide to carbon nitride materials. For these systems, we collate the current fundamental understanding of the electronic structure and its intrinsic connection with the catalytic properties of SACs. We conclude the chapter by providing a brief critical outlook in terms of unsolved challenges in the field.
