Screening of transition metal-based MOF as highly efficient bifunctional electrocatalysts for oxygen reduction and oxygen evolution

Designing efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is momentous for energy storage and conversion, as well as sustainable development. Herein, based on the recent prepared of two novel two-dimensional MOF materials, namely Ni–2D–SA and Ni–O–2D–SA, the replacement of Ni atoms in these two MOFs with 3d, 4d, and 5d transition metals is comprehensively investigated using density functional theory methods to screen out electrocatalysts with high bifunctional activity and stability for ORR and OER. Stability analysis indicates that some catalysts are thermodynamically and electrochemically stable. By calculating the overpotentials (ηORR and ηOER) and potential gap (∆E), it is found that Ir–2D–SA and Co–O–2D–SA possess the smallest ∆E values with 0.61 V (ηORR = 0.28 V, ηOER = 0.33 V) and 0.53 V (ηORR = 0.29 V, ηOER = 0.24 V), respectively, which are expected to be the most promising bifunctional electrocatalysts. The descriptor φ2 has proven that the binding strength for reaction intermediates is limited to active metal and environment around the active metal. Finally, all excellent catalysts have good resistance to poisoning. This work provides theoretical guidance for preparing efficient ORR and OER electrocatalysts.