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A sulfur-tethering synthesis strategy toward high-loading atomically dispersed noble metal catalysts

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Science Advances  25 Oct 2019:
Vol. 5, no. 10, eaax6322
DOI: 10.1126/sciadv.aax6322
  • Fig. 1 Schematic illustration of the preparation and model structure of the atomically dispersed noble metal catalysts.

    Five atomically dispersed noble metal (Ru, Rh, Pd, Ir, and Pt) catalysts were prepared on the meso_S-C supports with high metal loading of up to 10 wt %.

  • Fig. 2 Characterizations of Pt/meso_S-C.

    (A to D) HAADF-STEM images of (A) 5Pt/meso_S-C, (B) 10Pt/meso_S-C, (C) 20Pt/meso_S-C, and (D) 30Pt/meso_S-C. (E) XRD patterns of the Pt/meso_S-C catalysts. The standard peaks of Pt (JCPDS no. 04-0802) were shown in red lines. a.u., arbitrary units. (F) Normalized XANES spectra of 10Pt/meso_S-C, 30Pt/meso_S-C, H2PtCl6/meso_S-C, and Pt foil at the Pt L3-edge. (G) EXAFS spectra of 10Pt/meso_S-C, 30Pt/meso_S-C, Pt foil, and PtO2.

  • Fig. 3 Characterization of atomically dispersed noble metal catalysts.

    (A to D) HAADF-STEM images of (A) 5Ir/meso_S-C, (B) 5Rh/meso_S-C, (C) 5Pd/meso_S-C, and (D) 3Ru/meso_S-C. (E to H) Corresponding EXAFS spectra of (E) 5Ir/meso_S-C, (F) 5Rh/meso_S-C, (G) 5Pd/meso_S-C, and (H) 3Ru/meso_S-C at R space. EXAFS spectra of metal oxide and foil were also shown for comparison.

  • Fig. 4 Catalytic performance of atomically dispersed noble metal catalysts.

    (A) FAOR anodic sweep voltammograms of the atomically Pt/meso_S-C and reference catalysts, as normalized by the Pt mass. The inset shows the magnified curve of Pt/C. Test conditions: sweep rate, 10 mV s−1; 0.5 M H2SO4; 0.5 M HCOOH; and Pt loading, 10.2 μg cm−2 for all samples. (B) Comparison of the mass activity of the catalysts for FAOR at 0.6 V. (C) Catalytic performance of quinoline hydrogenation over 5Ir/meso_S-C and reference catalysts. (D) Recycle of 10Ir/meso_S-C for catalytic hydrogenation of quinoline.

  • Table 1 XAFS fitting parameters of Pt species in Pt/meso_S-C and reference materials.

    N, coordination number for the absorber-backscatterer pair; R, the average absorber-backscatterer distance; σ2, the Debye-Waller factor; ΔE0 is the inner potential correction; r factor shows the goodness of the fit. The k range for Fourier transformation was from 2.5 to 12.4 Å−1 and the fitted R range was from 1.1 to 3.2 Å.

    SampleShellNR (Å)σ2 (10−3 Å2)ΔE0 (eV)r factor
    Pt foilPt-Pt12 (fixed)2.763 ± 0.0034.5 ± 0.46.90 ± 0.430.002
    PtO2Pt-O6 (fixed)1.987 ± 0.0094.1 ± 0.78.1 ± 1.20.024
    Pt-Pt6 (fixed)3.102 ± 0.0072.9 ± 0.59.9 ± 0.2
    5Pt/meso_S-CPt-S3.6 ± 0.32.270 ± 0.0073.4 ± 0.73.06 ± 0.460.007
    10Pt/meso_S-CPt-S3.6 ± 0.32.264 ± 0.0073.4 ± 0.73.06 ± 0.460.004
    20Pt/meso_S-CPt-S2.8 ± 0.32.261 ± 0.0085.2 ± 0.93.06 ± 0.460.002
    Pt-Pt2.3 ± 0.72.717 ± 0.0369.3 ± 2.46.90 ± 0.43
    30Pt/meso_S-CPt-S2.2 ± 0.22.267 ± 0.0076.1 ± 0.83.06 ± 0.460.003
    Pt-Pt4.4 ± 0.62.734 ± 0.0058.8 ± 0.96.90 ± 0.43
  • Table 2 Hydrogenation of various quinoline derivatives on the 5Ir/meso_S-C catalyst.

    Reaction condition: T = 100°C, P = 2 MPa, 2 hours, Ir/substrate = 0.1 at %, 0.5 mmol substrate, 1 ml ethanol as solvent, o-xylene as standard.


    Embedded Image

    *T = 120°C.

    T = 120°C, 3 hours.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/10/eaax6322/DC1

      Fig. S1. TPR and XPS characterizations.

      Fig. S2. Structure characterizations and models of Pt/meso_S-C.

      Fig. S3. HAADF-STEM images of 5 wt % Pt on reference supports.

      Fig. S4. Structure characterizations of Ir/meso_S-C.

      Fig. S5. HAADF-STEM images of additional Pd, Rh, and Ru catalysts.

      Fig. S6. Stability of the catalysts for FAOR.

      Fig. S7. HAADF-STEM images of the 10Ir/meso_S-C catalyst after five cycles.

      Table S1. Physicochemical properties of meso_S-C and other reference carbon supports.

      Table S2. XAFS fitting parameters of Ir species in Ir/meso_S-C and Ir powder.

    • Supplementary Materials

      This PDF file includes:

      • Fig. S1. TPR and XPS characterizations.
      • Fig. S2. Structure characterizations and models of Pt/meso_S-C.
      • Fig. S3. HAADF-STEM images of 5 wt % Pt on reference supports.
      • Fig. S4. Structure characterizations of Ir/meso_S-C.
      • Fig. S5. HAADF-STEM images of additional Pd, Rh, and Ru catalysts.
      • Fig. S6. Stability of the catalysts for FAOR.
      • Fig. S7. HAADF-STEM images of the 10Ir/meso_S-C catalyst after five cycles.
      • Table S1. Physicochemical properties of meso_S-C and other reference carbon supports.
      • Table S2. XAFS fitting parameters of Ir species in Ir/meso_S-C and Ir powder.

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