Fig. 1 Synthetic scheme and morphology characterization of FeN5SA/CNF. (A) Schematic formation process of carbon nanoframe–confined atomically dispersed Fe sites with axial five-N coordination for mimicking the active center of cytocrome P450. (B and C) TEM images and (D) high-angle annular dark-field STEM (HAADF-STEM) image of FeN5 SA/CNF. (E and F) Magnified HAADF-STEM images of FeN5 SA/CNF showing the dominant metal single atom. (G) EELS mapping images of FeN5 SA/CNF of the selected region in (D). Scale bars, 1 μm and 100, 100, 5, 2, and 50 nm (B to G, respectively).
Fig. 2 Atomic structure characterization of FeN5SA/CNF. (A) XPS spectrum of N 1s. a.u., arbitrary unit. (B) Normalized XANES spectra at Fe K-edge of the Fe foil, Fe2O3, FePc, and FeN5 SA/CNF and (C) the corresponding k3-weighted Fourier-transformed spectra. (D) Fitting curves of the EXAFS of FeN5 SA/CNF in the r-space and k-space [inset of (D)].
Fig. 3 Oxidase-like activity of FeN5SA/CNF. (A) Schematic illustration of oxidase-like characteristics of FeN5 SA/CNF–catalyzed TMB oxidation. (B) Ultraviolet-visible (UV-vis) absorption spectra of FeN5 SA/CNF in O2-saturated, air-saturated, and N2-saturated sodium acetate–acetic acid buffer. (C) The durability of FeN5 SA/CNF treated with acid (alkali) for 21 hours. (D) Time-dependent absorbance changes at 652 nm, (E) histogram of V0, and (F) typical Michaelis-Menten curves in the presence of FeN5 SA/CNF (i), MnN5 SA/CNF (ii), CoN5 SA/CNF (iii), FeN4 SA/CNF (iv), NiN5 SA/CNF (v), and CuN5 SA/CNF (vi) in air-saturated sodium acetate–acetic acid buffer. The inset of (E) is an optical image of the TMB solution catalyzed by corresponding catalysts. Photo credit: Liang Huang, Changchun Institute of Applied Chemistry.
Fig. 4 Theoretical investigation of oxidase-like activity over FeN5SA/CNF. (A) Proposed reaction pathways of O2 reduction to H2O with optimized adsorption configurations on FeN5 SA/CNF. The gray, blue, purple, red, and white balls represent the C, N, Fe, O, and H atoms, respectively. (B) Free energy diagram for oxygen reduction reaction on single-atom enzyme mimics with TMB as reductant in an acidic medium.
Supplementary Materials
Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/5/eaav5490/DC1
Fig. S1. The structures of cytocrome P450, horseradish peroxidase, and catalase and the corresponding active center.
Fig. S2. Morphology of the Zn-MOF precursor.
Fig. S3. Structure of the Zn-MOF precursor.
Fig. S4. FTIR spectra of FePc, Zn-MOF, and FePc@Zn-MOF.
Fig. S5. Morphology and structure of FeN5 SA/CNF.
Fig. S6. Surface area and pore structure characterization.
Fig. S7. HRTEM images of FeN5 SA/CNF.
Fig. S8. XPS and Mössbauer spectra of FeN5 SA/CNF.
Fig. S9. Morphology and atomic structure of FeN5 SA/CNF@800°C.
Fig. S10. Morphology and atomic structure of FeN5 SA/CNF@1000°C.
Fig. S11. Morphology and atomic structure of FeN4 SA/CNF.
Fig. S12. Morphology and atomic structure of MnN5 SA/CNF.
Fig. S13. Morphology and atomic structure of CoN5 SA/CNF.
Fig. S14. Morphology and atomic structure of NiN5 SA/CNF.
Fig. S15. Morphology and atomic structure of CuN5 SA/CNF.
Fig. S16. UV-vis absorption spectra of the catalysts.
Fig. S17. Oxidase-like activities of FeN5 SA/CNF in different conditions.
Fig. S18. UV-vis absorption spectra of FeN5 SA/CNF.
Fig. S19. Morphology and structure of synthesized conventional nanozymes.
Fig. S20. UV-vis absorption spectra of TMB solutions.
Fig. S21. Morphological changes in bacteria.
Fig. S22. In vitro cytotoxicity experiments.
Fig. S23. Photographs of in vivo mice wound model.
Fig. S24. Double-reciprocal plots of activity of these catalysts.
Fig. S25. The analysis of the intermediate state of and active center in FeN5 SA/CNF.
Fig. S26. Theoretical investigation of oxidase-like activity.
Table S1. Mössbauer parameters of FeN5 SA/CNF.
Table S2. Comparison of oxidase-like activity of synthesized catalysts.
Table S3. Comparison of the kinetic constants of the single-atom enzyme mimics.
Table S4. The adsorption energy on the single-atom catalysts.
Table S5. Reaction free energy of intermediate species on single-atom catalysts.
Table S6. Comparison of the kinetic constants of FeN5 SA/CNF and nanozymes.
References (44–51)
Additional Files
Supplementary Materials
This PDF file includes:
- Fig. S1. The structures of cytocrome P450, horseradish peroxidase, and catalase and the corresponding active center.
- Fig. S2. Morphology of the Zn-MOF precursor.
- Fig. S3. Structure of the Zn-MOF precursor.
- Fig. S4. FTIR spectra of FePc, Zn-MOF, and FePc@Zn-MOF.
- Fig. S5. Morphology and structure of FeN5 SA/CNF.
- Fig. S6. Surface area and pore structure characterization.
- Fig. S7. HRTEM images of FeN5 SA/CNF.
- Fig. S8. XPS and Mössbauer spectra of FeN5 SA/CNF.
- Fig. S9. Morphology and atomic structure of FeN5 SA/CNF@800°C.
- Fig. S10. Morphology and atomic structure of FeN5 SA/CNF@1000°C.
- Fig. S11. Morphology and atomic structure of FeN4 SA/CNF.
- Fig. S12. Morphology and atomic structure of MnN5 SA/CNF.
- Fig. S13. Morphology and atomic structure of CoN5 SA/CNF.
- Fig. S14. Morphology and atomic structure of NiN5 SA/CNF.
- Fig. S15. Morphology and atomic structure of CuN5 SA/CNF.
- Fig. S16. UV-vis absorption spectra of the catalysts.
- Fig. S17. Oxidase-like activities of FeN5 SA/CNF in different conditions.
- Fig. S18. UV-vis absorption spectra of FeN5 SA/CNF.
- Fig. S19. Morphology and structure of synthesized conventional nanozymes.
- Fig. S20. UV-vis absorption spectra of TMB solutions.
- Fig. S21. Morphological changes in bacteria.
- Fig. S22. In vitro cytotoxicity experiments.
- Fig. S23. Photographs of in vivo mice wound model.
- Fig. S24. Double-reciprocal plots of activity of these catalysts.
- Fig. S25. The analysis of the intermediate state of and active center in FeN5 SA/CNF.
- Fig. S26. Theoretical investigation of oxidase-like activity.
- Table S1. Mössbauer parameters of FeN5 SA/CNF.
- Table S2. Comparison of oxidase-like activity of synthesized catalysts.
- Table S3. Comparison of the kinetic constants of the single-atom enzyme mimics.
- Table S4. The adsorption energy on the single-atom catalysts.
- Table S5. Reaction free energy of intermediate species on single-atom catalysts.
- Table S6. Comparison of the kinetic constants of FeN5 SA/CNF and nanozymes.
- References (44–51)
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