Reversible loss of core–shell structure for Ni–Au bimetallic nanoparticles during CO2 hydrogenation

Abstract

The high catalytic performance of core–shell nanoparticles is usually attributed to their distinct geometric and electronic structures. Here we reveal a dynamic mechanism that overturns this conventional understanding by a direct environmental transmission electron microscopy visualization coupled with multiple state-of-the-art in situ techniques, which include synchrotron X-ray absorption spectroscopy, infrared spectroscopy and theoretical simulations. A Ni–Au catalytic system, which exhibits a highly selective CO production in CO2 hydrogenation, features an intact ultrathin Au shell over the Ni core before and after the reaction. However, the catalytic performance could not be attributed to the Au shell surface, but rather to the formation of a transient reconstructed alloy surface, promoted by CO adsorption during the reaction. The discovery of such a reversible transformation urges us to reconsider the reaction mechanism beyond the stationary model, and may have important implications not only for core–shell nanoparticles, but also for other well-defined nanocatalysts.

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Fig. 1: Microstructure and catalytic performance of NiAu/SiO2.
Fig. 2: In situ observation of the structural transition of NiAu NPs during the reaction.
Fig. 3: Catalysis mechanism in the structural evolution of NiAu.

Data availability

All the data needed to support the plots and evaluate the conclusions within this article are present within it, the Supplementary Information or the Cambridge Crystallographic Data Centre (deposition no. CSD 1979031-1979068), or are available from the corresponding author upon reasonable request.

References

  1. 1.

    Hansen, P. L. et al. Atom-resolved imaging of dynamic shape changes in supported copper nanocrystals. Science 295, 2053–2055 (2002).

    CAS  Article  Google Scholar 

  2. 2.

    Nolte, P. et al. Shape changes of supported Rh nanoparticles during oxidation and reduction cycles. Science 321, 1654–1658 (2008).

    CAS  Article  Google Scholar 

  3. 3.

    Yoshida, H. et al. Visualizing gas molecules interacting with supported nanoparticulate catalysts at reaction conditions. Science 335, 317–319 (2012).

    CAS  Article  Google Scholar 

  4. 4.

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

    CAS  Article  Google Scholar 

  5. 5.

    Wei, X. et al. Geometrical structure of the gold–iron(iii) oxide interfacial perimeter for CO oxidation. Angew. Chem. Int. Ed. 57, 11289–11293 (2018).

    CAS  Article  Google Scholar 

  6. 6.

    Gawande, M. B. et al. Core–shell nanoparticles: synthesis and applications in catalysis and electrocatalysis. Chem. Soc. Rev. 44, 7540–7590 (2015).

    CAS  Article  Google Scholar 

  7. 7.

    Bhattarai, N., Casillas, G., Ponce, A. & Jose-Yacaman, M. Strain-release mechanisms in bimetallic core–shell nanoparticles as revealed by Cs-corrected STEM. Surf. Sci. 609, 161–166 (2013).

    CAS  Article  Google Scholar 

  8. 8.

    Bu, L. et al. Biaxially strained PtPb/Pt core/shell nanoplate boosts oxygen reduction catalysis. Science 354, 1410–1414 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    Tedsree, K. et al. Hydrogen production from formic acid decomposition at room temperature using a Ag–Pd core–shell nanocatalyst. Nat. Nanotechnol. 6, 302–307 (2011).

    CAS  Article  Google Scholar 

  10. 10.

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

    CAS  Article  Google Scholar 

  11. 11.

    Zhan, W. C. et al. Crystal structural effect of AuCu alloy nanoparticles on catalytic CO oxidation. J. Am. Chem. Soc. 139, 8846–8854 (2017).

    CAS  Article  Google Scholar 

  12. 12.

    Chi, M. F. et al. Surface faceting and elemental diffusion behaviour at atomic scale for alloy nanoparticles during in situ annealing. Nat. Commun. 6, 8925 (2015).

    CAS  Article  Google Scholar 

  13. 13.

    Wang, F. et al. Tourmaline-modified FeMnTiOx catalysts for improved low-temperature NH3-SCR performance. Environ. Sci. Technol. 53, 6989–6996 (2019).

    CAS  Article  Google Scholar 

  14. 14.

    Vara, M. et al. Understanding the thermal stability of palladium–platinum core–shell nanocrystals by in situ transmission electron microscopy and density functional theory. ACS Nano 11, 4571–4581 (2017).

    CAS  Article  Google Scholar 

  15. 15.

    Wu, C. H. et al. Bimetallic synergy in cobalt–palladium nanocatalysts for CO oxidation. Nat. Catal. 2, 78–85 (2019).

    CAS  Article  Google Scholar 

  16. 16.

    Su, D. S., Zhang, B. & Schlogl, R. Electron microscopy of solid catalysts—transforming from a challenge to a toolbox. Chem. Rev. 115, 2818–2882 (2015).

    CAS  Article  Google Scholar 

  17. 17.

    Wang, D. & Li, Y. One-pot protocol for Au-based hybrid magnetic nanostructures via a noble-metal-induced reduction process. J. Am. Chem. Soc. 132, 6280–6281 (2010).

    CAS  Article  Google Scholar 

  18. 18.

    Duan, S., Wang, R. & Liu, J. Stability investigation of a high number density Pt1/Fe2O3 single-atom catalyst under different gas environments by HAADF-STEM. Nanotechnology 29, 204002 (2018).

    Article  Google Scholar 

  19. 19.

    Scherzer, O. The theoretical resolution limit of the electron microscope. J. Appl. Phys. 20, 20–29 (1949).

    CAS  Article  Google Scholar 

  20. 20.

    Pennycook, S. J. & Boatner, L. A. Chemically sensitive structure-imaging with a scanning transmission electron microscope. Nature 336, 565–567 (1988).

    CAS  Article  Google Scholar 

  21. 21.

    Williams, D. B. & Carter, C. B. (eds) Transmission Electron Microscopy: A Textbook for Materials Science 483–506 (Springer, 1996).

  22. 22.

    Hansen, T. W. & Wagner, J. B. Catalysts under controlled atmospheres in the transmission electron microscope. ACS Catal. 4, 1673–1685 (2014).

    CAS  Article  Google Scholar 

  23. 23.

    Xin, H. L., Niu, K., Alsem, D. H. & Zheng, H. In situ TEM study of catalytic nanoparticle reactions in atmospheric pressure gas environment. Microsc. Microanal. 19, 1558–1568 (2013).

    CAS  Article  Google Scholar 

  24. 24.

    Takenaka, S., Kobayashi, S., Ogihara, H. & Otsuka, K. Ni/SiO2 catalyst effective for methane decomposition into hydrogen and carbon nanofiber. J. Catal. 217, 79–87 (2003).

    CAS  Google Scholar 

  25. 25.

    Liu, X. et al. Structural changes of Au–Cu bimetallic catalysts in CO oxidation: in situ XRD, EPR, XANES, and FT-IR characterizations. J. Catal. 278, 288–296 (2011).

    CAS  Article  Google Scholar 

  26. 26.

    Ueckert, T., Lamber, R., Jaeger, N. I. & Schubert, U. Strong metal support interactions in a Ni/SiO2 catalyst prepared via sol–gel synthesis. Appl. Catal. A 155, 75–85 (1997).

    CAS  Article  Google Scholar 

  27. 27.

    Beniya, A., Isomura, N., Hirata, H. & Watanabe, Y. Low temperature adsorption and site-conversion process of CO on the Ni(111) surface. Surf. Sci. 606, 1830–1836 (2012).

    CAS  Article  Google Scholar 

  28. 28.

    Lang, R. et al. Non defect-stabilized thermally stable single-atom catalyst. Nat. Commun. 10, 234 (2019).

    Article  Google Scholar 

  29. 29.

    Yang, F., Yao, Y., Yan, Z., Min, H. & Goodman, D. W. Preparation and characterization of planar Ni–Au bimetallic model catalysts. Appl. Surf. Sci. 283, 263–268 (2013).

    CAS  Article  Google Scholar 

  30. 30.

    Mihaylov, M., Knözinger, H., Hadjiivanov, K. & Gates, B. C. Characterization of the oxidation states of supported gold species by IR spectroscopy of adsorbed CO. Chem. Ing. Tech. 79, 795–806 (2007).

    CAS  Article  Google Scholar 

  31. 31.

    Ruban, A. V., Skriver, H. L. & Nørskov, J. K. Surface segregation energies in transition-metal alloys. Phys. Rev. B 59, 15990–16000 (1999).

    Article  Google Scholar 

  32. 32.

    Swiatkowska-Warkocka, Z., Pyatenko, A., Krok, F., Jany, B. R. & Marszalek, M. Synthesis of new metastable nanoalloys of immiscible metals with a pulse laser technique. Sci. Rep. 5, 9849 (2015).

    CAS  Article  Google Scholar 

  33. 33.

    Liu, W., Sun, K. & Wang, R. In situ atom-resolved tracing of element diffusion in NiAu nanospindles. Nanoscale 5, 5067–5072 (2013).

    CAS  Article  Google Scholar 

  34. 34.

    Porosoff, M. D., Yan, B. & Chen, J. G. Catalytic reduction of CO2 by H2 for synthesis of CO, methanol and hydrocarbons: challenges and opportunities. Energ. Environ. Sci. 9, 62–73 (2016).

    CAS  Article  Google Scholar 

  35. 35.

    Duan, S. & Wang, R. Au/Ni12P5 core/shell nanocrystals from bimetallic heterostructures: in situ synthesis, evolution and supercapacitor properties. NPG Asia Mater. 6, e122 (2014).

    CAS  Article  Google Scholar 

  36. 36.

    Wong, A., Liu, Q., Griffin, S., Nicholls, A. & Regalbuto, J. R. Synthesis of ultrasmall, homogeneously alloyed, bimetallic nanoparticles on silica supports. Science 358, 1427–1430 (2017).

    CAS  Article  Google Scholar 

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Acknowledgements

This work received financial support from Talents Innovation Project of Dalian (2016RD04), CAS Youth Innovation Promotion Association (2019190) and the Natural Science Foundation of China (21773287, 11604357, 21872145, 21902019, 11574340 and 51874115); G.Z. and J.T.M. were supported in part by the National Science Foundation under Cooperative Agreement no. EEC-1647722. G.Z. also acknowledges the Fundamental Research Funds for Central Universities (DUT18RC(3)057). B.Z. thanks the financial support of the Key Research Program of Frontier Sciences, CAS, Grant no. ZDBS-LY-7012. Use of the Advanced Photon Source was supported by the US Department of Energy, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. MRCAT operations, beamline 10-BM, are supported by the Department of Energy and the MRCAT member institutions; the computational resources utilized in this research were provided by the National Supercomputing Center in Guangzhou (NSCC-GZ), Tianjin and Shanghai. In situ TEM work was also supported by NSFC 21802065 and was partially conducted at the picocenter of SUSTech CRF that receives funding from the Shenzhen government. We especially acknowledge H. Matsumoto and C. Zeng from Hitachi High-Technologies Co., Ltd, for the in situ STEM characterization; S. Liu from Dalian Jiaotong University for the focusing filtering and alignment on HRTEM images via scripting. This work is dedicated to the late D. Su for his valuable support and discussions.

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Authors

Contributions

The project was conceived by W.L. X.Z. performed the catalyst preparation, FTIR and partial TEM characterizations and data analysis under the supervision of W.L. S.H. and M.G. conducted part of the ETEM experiments and data analysis. B.Z., X.L. and Y.G. conducted the mechanism analysis via DFT calculations as well as the manuscript preparation. G.Z. and J.T.M. performed the in situ XAS measurements and structure analysis. Z.W. contributed to the catalyst preparation and reaction measurements. B.Y. performed part of the FTIR experiments and data analysis. Y.L., W.B. and O.E. conducted the in situ TEM experiment under atmospheric pressure.

Corresponding authors

Correspondence to Yi Gao or Bing Yang or Meng Gu or Wei Liu.

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Supplementary information

Supplementary Information

Supplementary methods, discussion, Figs. 1–20, Tables 1 and 2, and references.

Supplementary Data Set

Supplementary Video 1

In situ TEM video of the heating process at a pressure of ~9 mbar of 25% CO2 + 75% H2 from 500 to 600 °C at ×50 playback speed.

Supplementary Video 2

In situ TEM video of the cooling process at a pressure of ~9 mbar of 25% CO2 + 75% H2 from 600 to 400 °C at ×50 playback speed.

Supplementary Video 3

In situ SAED video of the heating process at a pressure of ~9 mbar of 25% CO2 + 75% H2 from 300 to 500 °C at ×10 playback speed.

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Zhang, X., Han, S., Zhu, B. et al. Reversible loss of core–shell structure for Ni–Au bimetallic nanoparticles during CO2 hydrogenation. Nat Catal 3, 411–417 (2020). https://doi.org/10.1038/s41929-020-0440-2

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