Computational Screening of Two-Dimensional Metal-Organic Frameworks as Efficient Single-Atom Catalysts for Oxygen Reduction Reaction

The development of efficient and inexpensive oxygen reduction reaction (ORR) catalysts is crucial for renewable energy technologies. Herein, using density functional theory (DFT) methods and microkinetic simulations, we systematically investigated the ORR catalytic performance of a series of 2D metal-organic frameworks M-3(HADQ)(2) (HADQ=2,3,6,7,10,11-hexaamine dipyrazino quinoxaline). It shows that all 2D M-3(HADQ)(2) (M=Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh and Pd) monolayers are metallic, due to pi-conjugated crystal orbitals centered on the central metals and ligand N atoms. The catalytic activity of M-3(HADQ)(2) depends on the binding strength between ORR intermediates and metal species, and can be tuned via changing the central metals. Among these candidates, Rh-3(HADQ)(2) and Co-3(HADQ)(2) show superior ORR performance to Pt (111) with high half-wave potentials of 0.99 and 0.93 V, respectively. Moreover, the screened two catalysts have excellent intermediate-tolerance ability for dynamic coverage of oxygenated species on the active sites. Our work provides a new path towards developing efficient ORR electrocatalysts.