Unraveling the Stability of N‐Doped Graphene Supported Single‐Atom and Dual‐Atom Catalysts From Pourbaix Diagram

Single-atom catalysts (SACs) and dual-atom catalysts (DACs) exhibit great potential in heterogeneous catalysis. However, studying their stability under practical reaction conditions remains a challenge. This work theoretically studies the electrochemical stability of N-doped graphene-supported SAC and DAC of five metals (Cr, Mn, Fe, Co, and Ni) under different pH and electric potentials. We propose a universal method that not only considers the chemical speciation of leached metal in solution (ions, hydroxides, and oxyanions) but also introduces structural modification for the substrate vacancy (binding with H). By constructing pH-potential dependent Gibbs free-energy criteria, Pourbaix diagrams (stability) for each catalyst without and with adsorbates were plotted. The results show that Co- and Ni-SAC possess good stability over a wide range of potentials and pH, and Co-SAC can be further stabilized by adsorbates (*H, *OH, or *OOH). Fe-SAC can only be stable with *H, *O, and *OOH, while Mn-SAC only exhibits stability with *O, under certain potentials and pH. Cr-SAC and Cr-, Mn-, Fe-DAC are unstable under all conditions. The stable regions of DAC are generally smaller than those of SAC, indicating potential difficulties in synthesis and applications. This study provides a theoretical model for evaluating and screening durable catalysts in realistic applications.