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Intermetallic nickel silicide nanocatalyst—A non-noble metal–based general hydrogenation catalyst

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Science Advances  08 Jun 2018:
Vol. 4, no. 6, eaat0761
DOI: 10.1126/sciadv.aat0761
  • Fig. 1 Catalysts characterization.

    (A) XRD data for Ni-phen@SiO2-1000 (blue) and Ni@SiO2-1000 (red). (B) X-ray photoelectron spectroscopy (XPS) measurement of the intermetallic nickel silicide catalyst Ni-phen@SiO2-1000. a.u., arbitrary units.

  • Fig. 2 Catalysts characterization.

    Scanning TEM (STEM)–high-angle annular dark-field (HAADF, top), annular bright-field (ABF) images and energy-dispersive x-ray (EDX) mapping of (A) Ni-phen@SiO2-1000 (free-standing Ni-Si nanoparticle embedded in carbon) and of (B) Ni@SiO2-1000 prepared without 1,10-phenanthroline ligand (no formation of intermetallic Ni-Si nanoparticles is observed, and Ni/NiO core-shell nanoparticles are formed).

  • Fig. 3 Formation of nickel silicide nanoparticles.
  • Scheme 1 Hydrogenation of nitroarenes with intermetallic Ni-Si catalyst Ni-phen@SiO2-1000.

    Reaction conditions: (A) Nitroarene (0.5 mmol), catalyst (40 mg; 4.0 mol % Ni), H2 (10 bar), 60°C, 20 hours, and 1:1 H2O/MeOH (2 ml). Isolated yields are reported unless otherwise indicated. (B to D) Nitrobenzene (0.5 mmol), Ni-phen@SiO2-1000 catalyst (40 mg; 4.0 mol % Ni), H2 (10 bar), 40°C, 20 hours, and 1:1 H2O/MeOH (2 ml). (D) Raney Ni catalyst (7.5 or 88 mg; 25 or 300 mol % Ni, respectively). a20 bar of H2, 80°C, 24 hours; bGC yields using n-hexadecane standard.

  • Scheme 2 Hydrogenation of other polar functional groups with intermetallic Ni–Si catalyst Ni-phen@SiO2-1000.

    Reaction conditions: (A) Substrate (0.5 mmol), catalyst (45 mg; 4.5 mol % Ni), H2 (20 bar), 80°C (aldehydes) or 100°C (ketones), 20 hours, and 1:1 H2O/MeOH (2 ml). (B and C) Nitrile (0.5 mmol), catalyst (45 mg; 4.5 mol % Ni), H2 (50 bar), 100°C (aromatic nitriles) or 130°C (aliphatic nitriles), 20 hours, and 7 M NH3/MeOH (2 ml). Isolated yields of hydrochloride salts. (D) Imine (0.25 mmol), catalyst (45 mg; 9.0 mol % Ni), H2 (50 bar ), 100°C, 16 hours, and 7 M NH3/MeOH (2 ml) or MeOH (2 ml). Isolated yields are reported unless otherwise indicated. a110°C; b120°C; c90 mg (9.0 mol % Ni); dGC yields using n-hexadecane standard; e150°C, 48 hours; fcomplete reduction of alkene; g2 ml of MeOH as a solvent.

  • Scheme 3 Hydrogenation of alkenes, alkynes, and quinolines and dehydrogenation of tetrahydroquinolines with intermetallic Ni–Si catalyst Ni-phen@SiO2-1000.

    Reaction conditions: (A) Substrate (0.5 mmol), catalyst (40 mg; 4.0 mol % Ni), H2 (10 bar), 40°C, 20 hours, and 1:1 H2O/MeOH (2 ml). GC yields using n-hexadecane standard, unless otherwise indicated. (B) Quinoline (0.5 mmol), catalyst (45 mg; 4.5 mol % Ni), H2 (50 bar), 120°C, 20 hours, and 1:1 H2O/MeOH (2 ml). Isolated yields. (C) Tetrahydroquinoline (0.5 mmol), catalyst (40 mg; 4.0 mol % Ni), air (10 bar), 100°C, 20 hours, and 1:1 H2O/MeOH (2 ml). Isolated yield. a60°C; b80°C; cisolated yield of hydrogenated product; dreaction time (48 hours); ealong with 4% of m-ethylbenzyl alcohol; falong with 6% of p-ethylbenzylamine; g90% conversion, 4% of p-ethylbenzylamine is formed. (D) Tetrahydroquinaldine (1.25 mmol), catalyst (500 mg; 20 mol % Ni), 200°C, 48 hours, triglyme (5 ml), and under Ar. Yield is determined by GC analysis of the liquid phase. Hydrogen evolution was measured by a manual burette.

  • Table 1 Hydrogenation of benchmark substrates with nickel-supported catalysts.
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Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/6/eaat0761/DC1

    section S1. Materials and methods

    section S2. Procedure for the catalyst preparation (fig. S1).

    section S3. TEM and EDX data (fig. S2 to S5)

    section S4. XRD diffraction patterns and data (figs. S6 to S10)

    section S5. XPS spectra and data (fig. S11)

    section S6. Elemental analysis of the catalysts and BET (fig. S12)

    section S7. Thermogravimetric analysis (TGA; figs. S13 and S14)

    section S8. Procedures for hydrogenation reactions (figs. S15 and S16)

    section S9. Product characterization

    section S10. Procedures for dehydrogenation reactions (figs. S17 to S19)

    section S11. Catalyst recycling

    section S12. Nuclear magnetic resonance (NMR) spectral charts

    fig. S1. Ni-phen@SiO2-1000 after pyrolysis.

    fig. S2. TEM images of the Ni-phen@SiO2-1000.

    fig. S3. ABF and HAADF-STEM images of intermetallic nickel silicide catalyst Ni-phen@SiO2-1000.

    fig. S4. HAADF-STEM and EDX measurement of the intermetallic nickel silicide catalyst Ni-phen@SiO2-1000.

    fig. S5. ABF-, HAADF-STEM, and EDX measurement of the catalyst Ni@SiO2-1000 prepared without ligand.

    fig. S6. Powder pattern of nickel-based catalysts supported on fumed silica.

    fig. S7. Powder pattern of Ni-phen@SiO2-800 measured up to 148°2θ.

    fig. S8. Powder pattern of various nickel-based catalysts with different ligands (S2.3).

    fig. S9. Powder pattern of various nickel-based catalysts on various supports.

    fig. S10. Powder pattern of nickel catalyst on silica gel and quartz (S2.3).

    fig. S11. XPS measurement of the intermetallic nickel silicide catalyst.

    fig. S12. N2 adsorption-desorption isotherms and BJH desorption pore size distribution.

    fig. S13. TG-DSC-MS analysis of Ni-phen@SiO2-1000.

    fig. S14. TG-DSC-MS analysis of Ni-phen@SiO2-1000.

    fig. S15. Autoclave and glass vials used for hydrogenations.

    fig S16. Concentration/time diagram for the hydrogenation of benzonitrile.

    fig. S17. Manual burette setup.

    fig. S18. Gas evolution from 1,2,3,4-tetrahydroquinaldine.

    fig. S19. Gas composition analysis by GC.

    table S1. Elemental analysis of the studied catalysts.

    table S2. BET surface area and pore volume of the samples.

    table S3. Hydrogenation of the standard substrates (Table 1 in the main text).

    table S4. Hydrogenation of the nitrobenzene with SiO2-supported catalysts.

    table S5. Recycling experiments.

    table S6. Nickel leaching in the recycling experiments.

    table S7. Effect of the pH on hydrogenation of nitrobenzene.

  • Supplementary Materials

    This PDF file includes:

    • section S1. Materials and methods
    • section S2. Procedure for the catalyst preparation (fig. S1).
    • section S3. TEM and EDX data (fig. S2 to S5)
    • section S4. XRD diffraction patterns and data (figs. S6 to S10)
    • section S5. XPS spectra and data (fig. S11)
    • section S6. Elemental analysis of the catalysts and BET (fig. S12)
    • section S7. Thermogravimetric analysis (TGA; figs. S13 and S14)
    • section S8. Procedures for hydrogenation reactions (figs. S15 and S16)
    • section S9. Product characterization
    • section S10. Procedures for dehydrogenation reactions (figs. S17 to S19)
    • section S11. Catalyst recycling
    • section S12. Nuclear magnetic resonance (NMR) spectral charts
    • fig. S1. Ni-phen@SiO2-1000 after pyrolysis.
    • fig. S2. TEM images of the Ni-phen@SiO2-1000.
    • fig. S3. ABF and HAADF-STEM images of intermetallic nickel silicide catalyst Ni-phen@SiO2-1000.
    • fig. S4. HAADF-STEM and EDX measurement of the intermetallic nickel silicide catalyst Ni-phen@SiO2-1000.
    • fig. S5. ABF-, HAADF-STEM, and EDX measurement of the catalyst Ni@SiO2-1000 prepared without ligand.
    • fig. S6. Powder pattern of nickel-based catalysts supported on fumed silica.
    • fig. S7. Powder pattern of Ni-phen@SiO2-800 measured up to 148°2θ.
    • fig. S8. Powder pattern of various nickel-based catalysts with different ligands (S2.3).
    • fig. S9. Powder pattern of various nickel-based catalysts on various supports.
    • fig. S10. Powder pattern of nickel catalyst on silica gel and quartz (S2.3).
    • fig. S11. XPS measurement of the intermetallic nickel silicide catalyst.
    • fig. S12. N2 adsorption-desorption isotherms and BJH desorption pore size distribution.
    • fig. S13. TG-DSC-MS analysis of Ni-phen@SiO2-1000.
    • fig. S14. TG-DSC-MS analysis of Ni-phen@SiO2-1000.
    • fig. S15. Autoclave and glass vials used for hydrogenations.
    • fig S16. Concentration/time diagram for the hydrogenation of benzonitrile.
    • fig. S17. Manual burette setup.
    • fig. S18. Gas evolution from 1,2,3,4-tetrahydroquinaldine.
    • fig. S19. Gas composition analysis by GC.
    • table S1. Elemental analysis of the studied catalysts.
    • table S2. BET surface area and pore volume of the samples.
    • table S3. Hydrogenation of the standard substrates (Table 1 in the main text).
    • table S4. Hydrogenation of the nitrobenzene with SiO2-supported catalysts.
    • table S5. Recycling experiments.
    • table S6. Nickel leaching in the recycling experiments.
    • table S7. Effect of the pH on hydrogenation of nitrobenzene.

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