Designing efficient single-atomic catalysts for bifunctional oxygen electrocatalysis via a general two-step strategy

The rational design of efficient electrocatalysts based on comprehensive mechanistic insights is crucial to widespread penetration of future sustainable and eco-friendly energy technologies. Herein, via systematic first-principles calculations, we propose a general two-step strategy for developing highly active single-atom catalyst (SACs) supported on a prototypical substrate (g-C3N4) for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Our results show that the intrinsic activity can be properly evaluated by a robust screening rule, and, particularly, the descriptor can be readily calculated by a few handy and basic properties. According to the knowledge, we propose an effective approach (i.e., creating an N vacancy in the cavity of g-C3N4) that enables further activity improvement. Specifically, the predicted ORR/OER activity on Ag and Rh based SACs are comparable or even outperforms that of respective benchmark catalysts. This study not only provides several promising candidates for bifunctional ORR/OER, but also directs a new avenue for rational design of high-performance catalysts.