A novel 2D Co3(HADQ)2 metal-organic framework as a highly active and stable electrocatalyst for acidic oxygen reduction

Efficient and robust electrocatalysts for acidic Oxygen reduction reaction (ORR) is crucial for the proton exchange membrane hydrogen fuel cells. However, the current electrocatalysts suffer from the stability issues in the acidic enviorment during ORR. Herein, we introduce a new layer-stacked two-dimensional (2D) metal-organic framework (MOF), Co3(HADQ)2 (HADQ = 2,3,6,7,10,11-hexaamine dipyrazino quinoxaline), synthesized for the first time. This novel MOF material shows the extremely high conductivity of 8,385.744 S/m with extraordinary activity (E1/2 = 0.836 V vs. RHE, n = 3.93, and jL = 5.31 mAcm−2) and an exceptional stability (up to 20,000 cycles) as the electrocatalyst for ORR in an acidic media (pH = 0.29), outperforming most of the state of the art Metal-N-C and single-atom electrocatalysts for acidic ORR. Density functional theory calculations indicate that the Co-sites are the active sites. We propose that Co3(HADQ)2 is a promising model catalyst for mechanistic studies of acidic ORR, due to its well defined and tunable structure.