Revealing the role of surface reconstruction and charge redistribution in M1M2-N4-Grs for bifunctional oxygen electrocatalysts

Abstract

Motivated by the effectiveness of carbon-based material catalysts in electrocatalytic reactions, we developed 55 M1M2-N4-Grs configurations (where M1, M2 = Sc to Zn) utilizing the novel graphene allotrope, Graphsene. These catalysts were evaluated for their catalytic performance in the oxygen reduction reaction and oxygen evolution reaction using density functional theory calculations. Several catalytic structures can be benchmarked against IrO₂ (110) and Pt (111). Notably, the Cu sites of CuCu–N4-Grs complexe manifest robust bifunctional activity, with overpotentials of 0.50/0.47 V for OER/ORR. Detailed electronic structure analysis reveals that Ti, Mn and Cu synergistically modulate the d-band center of catalytic site, and underscores the limitations of the d-band center as well as the integrated crystal orbital Hamilton population. A charge redistribution effect induced by surface reconstruction was found to further enhance the adsorption behavior of intermediates. Bader charge analysis identified the electronic gain of the ∗OH intermediate as crucial for catalytic activity. This study highlights the pivotal role of synergistic enhancement by bimetallic atomic sites and surface reconstruction in boosting catalytic performance, offering a theoretical framework for the development of efficient, non-precious metal bifunctional electrocatalysts.