Hemilabile Coordination in Single-Atom Catalyst: A Strategy To Overcome the Limitation of the Scaling Relationship.

Traditional catalyst optimization, based on the Sabatier principle, encounters performance limits due to the scaling relationship between binding energies for a series of adsorbates. This restriction prevents independent optimization of the reactant activation and product desorption. Single-atom catalysts (SACs) offer a unique advantage, with their ability to dynamically adjust the metal-support coordination environment. This flexibility allows us to apply hemilability, a concept from homogeneous catalysis, to modulate catalytic activity. Hemilability, which involves the reversible opening and closing of the coordination site, enables SACs to dynamically alter their electronic structure, effectively decoupling the competing requirements of activation and desorption. In this Perspective, we highlight how SACs, with hemilabile metal-support coordination, represent a promising strategy to bypass the limitations imposed by the scaling relationship. We also discuss the experimental challenges and future opportunities for directly observing and controlling these dynamic processes in SACs, thus presenting a powerful way for developing more efficient catalytic systems.