Nitrogen-coordinated single iron atom catalysts derived from metal organic frameworks for oxygen reduction reaction

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

“…For instance, the interaction between the reaction intermediates and a model Fe SACs (Fe–N–C) was investigated by combining in situ infrared absorption spectroscopy (ATR‐IR) and DFT calculations (Figure e) . The model Fe–N–C was synthesized by direct pyrolysis of Fe modified ZIF‐8 with the optimization of Fe/Zn ratio, heating temperature, and protective atmosphere . STEM (Figure d) and XAS analyses confirmed that atomically dispersed Fe atoms were well distributed along the edges of the porous carbon matrix with a FeN 4 configuration, supporting the hypothesis of the edge‐hosted FeN 2+2 model.…”

“…d) HAADF‐STEM images showing the Fe sites anchored along the edge of the carbon support. Reproduced with permission . Copyright 2019, Elsevier.…”

Standing Carbon‐Supported Trace Levels of Metal Derived from Covalent Organic Framework for Electrocatalysis

“…Differently, Co@COF 900 ‐leached still exhibited ORR activity in alkaline solution with E 1/2 of 0.73 V, and a j limit of 6.1 mA cm −2 (Figure d). The half‐wave potential of Co@COF 900 was more negative than that of recently reported single atom Co or Fe catalysts (e.g., Fe‐N‐C ( E 1/2 = 0.81 V), N/Fe‐CG (0.73 V), and Co‐N‐C‐10 ( E 1/2 = 0.79 V)), which may be caused by the low content of Co atoms. XPS measurement of Co@COF 900 detected no Co signal while N remained in the catalyst (Figure S17, Supporting Information).…”

“…Both Co‐N x sites and nitrogen functional groups contributed to the ORR activity in the alkaline electrolyte. The mass activity of cobalt in the acidic electrolyte can be calculated 13b. Accordingly, the mass activity of the Co@COF 900 achieved 838, 2272, 6020 mA mg −1 at 0.9, 0.7, and 0.5 V, which is higher than state‐of‐the‐art catalysts, such as 20Mn‐NC‐second,3a C‐FeZIF‐1.44‐950,2a and (Fe,Co)/N‐C (Table S3, Supporting Information).…”

Emerging Metal Single Atoms in Electrocatalysts and Batteries

“…[ 54 ] The common strategy for preparing the Fe SAs entails the utilization of Fe‐containing organic precursors, followed by pyrolysis under high temperature. So far, reported Fe‐containing organic precursors include Fe‐bipyridine, [ 55 ] Fe‐phthalocyanine, [ 56 ] Fe‐zeolitic imidazolate framework (ZIF)‐8, [ 57–59 ] Fe‐polypyrrole, [ 60–62 ] Fe‐porphyrinic triazine, [ 63 ] Fe‐imidazole‐melamine, [ 64 ] Fe‐1,3,5‐tris(4‐aminophenyl)‐benzene/terephthaldehyde, [ 65 ] Fe‐1,10 phenanthroline, [ 66 ] Fe‐pyrrole‐thiophene copolymer, [ 67 ] Fe‐histidine, [ 68 ] Fe‐porphyrinic MOFs, [ 69 ] Fe‐phthalocyanine/unsubstituted phthalocyanine, [ 70 ] Fe‐formamide, [ 71 ] Fe‐tetra(4′‐vinylphenyl)porphyrin, [ 72 ] Fe‐bis(imino)‐pyridine, [ 73 ] Fe‐phthalocyanine/ZIF‐8, [ 74 ] Fe‐melamine/lipoic acid, [ 75 ] Fe‐polydopamine, [ 76 ] Fe‐guanine, [ 77 ] Fe‐polyoxyethylene‐polyoxypropylene‐polyoxyethylene (pluronic F‐127), [ 78 ] Fe‐glucosamine hydrochloride, [ 79 ] Fe‐porphyra, [ 80 ] and ferrocene‐ZIF‐8. [ 81 ] For instance, Li et al.…”