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The two‐dimensional (2D) metal‐organic frameworks (MOFs) have capabilities to reduce CO2 with high Faradaic efficiency (FE). Herein, the role of incorporating bimetallic Ni and Fe into newly constructed MOFs is studied. This work highlights the use of bimetallic synergistic effect with surrounded nitrogen atoms, opening new avenues for efficient electrocatalytic reduction of CO2. This MOF Ni‐Fe contains moieties surrounded by four nitrogen atoms via covalent bonding, which resembles the porphyrin‐based molecular units as selective and effective homogeneous CO2 reduction electrocatalysts. Besides, density functional theory (DFT) also helps to figure out that the incorporation combination of metals helps achieve the high FE of 98.2% with stability up to 30 h under a low applied potential of −0.5 V versus reversible hydrogen electrode (RHE). These results offer a promising avenue to develop and optimize the MOFs‐based electrocatalysts for electrochemical conversion of CO2. [ABSTRACT FROM AUTHOR]

• A Novel layer-stacked well designed and highly crystalline 2D MOF named as Co 3 (HADQ) 2 MOF. • This Unique MOF features Co-N 4 motifs along with pyridinic Nitrogen (total N content: 28.6 at. %) as the active sites for ORR. • Outclass most of the electrocatalysts with a high activity (E 1/2 = 0.836 V vs. RHE, n = 3.93, and j L = 5.31 mAcm−2) in acidic media. • Exceptionally electrochemical stability up to 20,000 cycles for ORR in an acidic media at 0.29 pH. 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), Co 3 (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 (E 1/2 = 0.836 V vs. RHE, n = 3.93, and j L = 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 Co 3 (HADQ) 2 is a promising model catalyst for mechanistic studies of acidic ORR, due to its well defined and tunable structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-single atom anchored on carbon nanotubes catalyst was fabricated. • The catalyst exhibits excellent ORR catalytic activity in alkaline and acidic media. • The activity is boosted by the decorated Fe-N 4 on carbon nanotubes. Developing cost-effective and high-performance non-precious electrocatalysts for ORR in acidic and alkaline media is an urgent need for clean energy generation. A significant improvement in the ORR performance has been realized by the single-atom catalysts (SACs). However, activity deterioration caused by the dissolution of catalyst structure is still a lingering challenge. Herein, we report a simple strategy for protecting the structure of SAC by implanting/decorating Fe-ZIF-derived carbon nanotubes with Fe-N 4 , denoted as FeSA@CNTs. The as-developed FeSA@CNTs catalyst exhibits an outstanding ORR activity in an alkaline medium with onset potential (E o) = 0.998 V and half-wave potential E 1/2 = 0.898 V, which are 28 mV and 29 mV higher than commercial 20% Pt/C, respectively. Moreover, FeSA@CNTs in an acidic medium show an impressive high half-wave potential (E 1/2 = 0.8290 V) comparable to Pt/C (E 1/2 = 0.8292 V) which is better than most recently reported ORR catalysts. The density functional theory (DFT) validates that the smaller difference in the energy orbitals of Fe in Fe-N 4 and O 2 improved the electron transfer onto the reaction intermediate (OH*) in the rate-determining step, which provides the higher catalytic activity for FeSA@CNTs' in both acidic and alkaline media. [ABSTRACT FROM AUTHOR]