Roles of Coordination Geometry in Single-Atom Catalysts

Single-atom catalysts (SACs) have recently emerged as a new frontier for bridging the qualities of homogeneous and heterogeneous catalysts with 100% atomic utilization efficiency. The atomically dispersed characteristics of SACs always involve strong interactions between the metal centers and the neighboring atoms on supports. More importantly, the inherently atomic configurations resulting from metal–support interactions strongly influence their catalytic behaviors. Therefore, understanding the effects of the coordinative metal environment is extremely important for the design and preparation of new-generation SACs with high stability and rich functionalities. This chapter extensively discusses these aspects by highlighting state-of-the-art research progress on engineering the coordination geometries of metal single atoms and points out some foreseeable challenges and critical issues in the modulation of SAC active sites for further maintaining their catalytic superiority. Materials based on carbon, the most extensively explored support with a well-characterized coordination geometry, are particularly used as ideal examples.