Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Dynamic restructuring drives catalytic activity on nanoporous gold–silver alloy catalysts

Nature Materials volume 16, pages 558–564 (2017)Cite this article

Subjects

Abstract

Bimetallic, nanostructured materials hold promise for improving catalyst activity and selectivity, yet little is known about the dynamic compositional and structural changes that these systems undergo during pretreatment that leads to efficient catalyst function. Here we use ozone-activated silver–gold alloys in the form of nanoporous gold as a case study to demonstrate the dynamic behaviour of bimetallic systems during activation to produce a functioning catalyst. We show that it is these dynamic changes that give rise to the observed catalytic activity. Advanced in situ electron microscopy and X-ray photoelectron spectroscopy are used to demonstrate that major restructuring and compositional changes occur along the path to catalytic function for selective alcohol oxidation. Transient kinetic measurements correlate the restructuring to three types of oxygen on the surface. The direct influence of changes in surface silver concentration and restructuring at the nanoscale on oxidation activity is demonstrated. Our results demonstrate that characterization of these dynamic changes is necessary to unlock the full potential of bimetallic catalytic materials.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Activation of npAu for selective methanol oxidation.
Figure 2: Pulsed experiments over ozone-treated npAu.
Figure 3: E-TEM analysis of npAu after ozone treatment.
Figure 4: E-TEM analysis of npAu during CO and CH3OH exposure.
Figure 5: AP-XPS analysis of npAu.
Figure 6: Changes in the relative surface concentrations of Ag, O and Au.

Similar content being viewed by others

References

  1. Behrens, M. et al. The active site of methanol synthesis over Cu/ZnO/Al2O3 industrial catalysts. Science 336, 893–897 (2012).

    Article  CAS  Google Scholar 

  2. Xin, H. L. et al. Revealing the atomic restructuring of Pt–Co nanoparticles. Nano Lett. 14, 3203–3207 (2014).

    Article  CAS  Google Scholar 

  3. Tao, F. et al. Reaction-driven restructuring of Rh–Pd and Pt–Pd core–shell nanoparticles. Science 322, 932–934 (2008).

    Article  CAS  Google Scholar 

  4. Brett, G. L. et al. Selective oxidation of glycerol by highly active bimetallic catalysts at ambient temperature under base-free conditions. Angew. Chem. 123, 10318–10321 (2011).

    Article  Google Scholar 

  5. Della Pina, C., Falletta, E. & Rossi, M. Highly selective oxidation of benzyl alcohol to benzaldehyde catalyzed by bimetallic gold–copper catalyst. J. Catalys. 260, 384–386 (2008).

    Article  CAS  Google Scholar 

  6. Whiting, G. T. et al. Methyl formate formation from methanol oxidation using supported gold–palladium nanoparticles. ACS Catalys. 5, 637–644 (2015).

    Article  CAS  Google Scholar 

  7. Kotionova, T. et al. Oxidative esterification of homologous 1,3-propanediols. Catalys. Lett. 142, 1114–1120 (2012).

    Article  CAS  Google Scholar 

  8. Suzuki, K. et al. Aerobic oxidative esterification of aldehydes with alcohols by gold–nickel oxide nanoparticle catalysts with a core–shell structure. ACS Catalys. 3, 1845–1849 (2013).

    Article  CAS  Google Scholar 

  9. Stowers, K. J., Madix, R. J. & Friend, C. M. From model studies on Au(111) to working conditions with unsupported nanoporous gold catalysts: oxygen-assisted coupling reactions. J. Catalys. 308, 131–141 (2013).

    Article  CAS  Google Scholar 

  10. Wang, L.-C. et al. Exploiting basic principles to control the selectivity of the vapor phase catalytic oxidative cross-coupling of primary alcohols over nanoporous gold catalysts. J. Catalys. 329, 78–86 (2015).

    Article  CAS  Google Scholar 

  11. Sault, A. G., Madix, R. J. & Campbell, C. T. Adsorption of oxygen and hydrogen on Au(110)-(1 × 2). Surf. Sci. 169, 347–356 (1986).

    Article  CAS  Google Scholar 

  12. Meyer, R., Lemire, C., Shaikhutdinov, S. K. & Freund, H. J. Surface chemistry of catalysis by gold. Gold Bull. 37, 72–124 (2011).

    Article  Google Scholar 

  13. Personick, M. L. et al. Ozone-activated nanoporous gold: a stable and storable material for catalytic oxidation. ACS Catalys. 5, 4237–4241 (2015).

    Article  CAS  Google Scholar 

  14. Xu, C. et al. Low temperature CO oxidation over unsupported nanoporous gold. J. Am. Chem. Soc. 129, 42–43 (2007).

    Article  CAS  Google Scholar 

  15. Biener, M. M. et al. ALD functionalized nanoporous gold: thermal stability, mechanical properties, and catalytic activity. Nano Lett. 11, 3085–3090 (2011).

    Article  CAS  Google Scholar 

  16. Fujita, T. et al. Atomic origins of the high catalytic activity of nanoporous gold. Nat. Mater. 11, 775–780 (2012).

    Article  CAS  Google Scholar 

  17. Xu, B., Liu, X., Haubrich, J., Madix, R. J. & Friend, C. M. Selectivity control in gold-mediated esterification of methanol. Angew. Chem. Int. Ed. 48, 4206–4209 (2009).

    Article  CAS  Google Scholar 

  18. Xu, B., Haubrich, J., Freyschlag, C. G., Madix, R. J. & Friend, C. M. Oxygen-assisted cross-coupling of methanol with alkyl alcohols on metallic gold. Chem. Sci. 1, 310–316 (2010).

    Article  CAS  Google Scholar 

  19. Wang, L. C. et al. Active sites for methanol partial oxidation on nanoporous gold catalysts. J. Catalys. 344, 778–783 (2016).

    Article  CAS  Google Scholar 

  20. in Non-tetrahedrally Bonded Elements and Binary Compounds I Vol. 41C (eds Madelung, O., Rössler, U. & Schulz, M.) 1–3 (Springer, 1998).

  21. Jones, P. G. et al. Gold(III) oxide. Acta Crystallogr. B 35, 1435–1437 (1979).

    Article  Google Scholar 

  22. Krozer, A. & Rodahl, M. X-ray photoemission spectroscopy study of UV/ozone oxidation of Au under ultrahigh vacuum conditions. J. Vac. Sci. Technol. A 15, 1704–1707 (1997).

    Article  CAS  Google Scholar 

  23. Tanuma, S., Powell, C. J. & Penn, D. R. Calculations of electron inelastic mean free paths. Surf. Interface Anal. 21, 165–176 (1994).

    Article  CAS  Google Scholar 

  24. Kaspar, T. C., Droubay, T., Chambers, S. A. & Bagus, P. S. Spectroscopic evidence for Ag(III) in highly oxidized silver films by X-ray photoelectron spectroscopy. J. Phys. Chem. C 114, 21562–21571 (2010).

    Article  CAS  Google Scholar 

  25. Hammond, J. S. & Gaarenstroom, S. W. X-ray photoelectron spectroscopic studies of cadmium– and silver–oxygen surfaces. Anal. Chem. 47, 2193–2199 (1975).

    Article  CAS  Google Scholar 

  26. Hoflund, G. B., Hazos, Z. F. & Salaita, G. N. Surface characterization study of Ag, AgO, and Ag2O using x-ray photoelectron spectroscopy and electron energy-loss spectroscopy. Phys. Rev. B 62, 11126–11133 (2000).

    Article  CAS  Google Scholar 

  27. Xu, B., Siler, C. G. F., Madix, R. J. & Friend, C. M. Ag/Au mixed sites promote oxidative coupling of methanol on the alloy surface. Chem. Eur. J. 20, 4646–4652 (2014).

    Article  CAS  Google Scholar 

  28. Boronin, A. I., Koscheev, S. V. & Zhidomirov, G. M. XPS and UPS study of oxygen states on silver. J. Electron Spectrosc. Relat. Phenom. 96, 43–51 (1998).

    Article  CAS  Google Scholar 

  29. Tyson, C. C. et al. Charge redistribution in Au–Ag alloys from a local perspective. Phys. Rev. B 45, 8924–8928 (1992).

    Article  CAS  Google Scholar 

  30. Kibis, L. S. et al. The investigation of oxidized silver nanoparticles prepared by thermal evaporation and radio-frequency sputtering of metallic silver under oxygen. Appl. Surf. Sci. 257, 404–413 (2010).

    Article  CAS  Google Scholar 

  31. Moskaleva, L. V., Weiss, T., Klüner, T. & Bäumer, M. Chemisorbed oxygen on the Au(321) surface alloyed with silver: a first-principles investigation. J. Phys. Chem. C 119, 9215–9226 (2015).

    Article  CAS  Google Scholar 

  32. Fujita, T. et al. Atomic observation of catalysis-induced nanopore coarsening of nanoporous gold. Nano Lett. 14, 1172–1177 (2014).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under award no. DE-SC0012573. Work at LLNL was performed under the auspices of the US Department of Energy by LLNL under Contract DE-AC52-07NA27344. This research used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. It also used resources of the Advance Light Source, which is supported by the Office of Science of the US DOE under Contract No. DE-AC02-05CH11231. We thank H. Bluhm for advice on the preparation of the AP-XPS experiments and H. Xin for valuable discussion regarding the EELS data.

Author information

Authors and Affiliations

  1. Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA

    Branko Zugic, Lucun Wang & Cynthia M. Friend

  2. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

    Christian Heine, Barbara A. J. Lechner & Miquel Salmeron

  3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA

    Dmitri N. Zakharov & Eric A. Stach

  4. Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California 94550, USA

    Juergen Biener

  5. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

    Robert J. Madix & Cynthia M. Friend

Authors
  1. Branko Zugic
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Lucun Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Christian Heine
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Dmitri N. Zakharov
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Barbara A. J. Lechner
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Eric A. Stach
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Juergen Biener
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Miquel Salmeron
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Robert J. Madix
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Cynthia M. Friend
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

C.M.F., R.J.M., J.B. and B.Z. conceived and designed the experimental plan. B.Z. conducted the flow reactor experiments. B.Z. and J.B. prepared the npAu samples. L.W. conceived and conducted the TAP reactor experiments. C.H., M.S., B.A.J.L. and B.Z. conceived and conducted the AP-XPS experiments and analysed the XPS data. E.A.S., D.N.Z. and B.Z. planned and conducted E-TEM experiments. B.Z. wrote the initial draft of the manuscript. All authors discussed the results and contributed to the final preparation of the manuscript.

Corresponding author

Correspondence to Cynthia M. Friend.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1325 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zugic, B., Wang, L., Heine, C. et al. Dynamic restructuring drives catalytic activity on nanoporous gold–silver alloy catalysts. Nature Mater 16, 558–564 (2017). https://doi.org/10.1038/nmat4824

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat4824

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing