Through the Self-Optimization process to achieve high OER activity of SAC catalysts within the framework of TMO3@G and TMO4@G: A High-Throughput theoretical study

High-throughput DFT calculations are performed to explore the oxygen evolution reaction (OER) catalytic activity of a series of 2D graphene-based systems with TMO3 or TMO4 functional units. By screening the 3d/4d/5d transition metal (TM) atoms, a total of twelve TMO3@G or TMO4@G systems had extremely low overpotential of 0.33 ∼ 0.59 V, in which the V/Nb/Ta atom in VB group and Ru/Co/Rh/Ir atom in VIII group served as the active sites. The mechanism analysis reveals that the filling of outer electrons of TM atom can play an important role in determining the overpotential value by affecting the ΔGO* value as an effective descriptor. Especially, in addition to the general situation of OER on the clean surface of the systems containing the Rh/Ir metal centers, the self-optimization process of TM-sites was carried out, and it made most of these single-atom catalysts (SAC) systems to have high OER catalytic activity. All these fascinating findings can contribute to an in-depth understanding of the OER catalytic activity and mechanism of the excellent graphene-based SAC systems. This work will facilitate the design and implementation of non-precious and highly efficient OER catalysts in the near future.