Bimetallic synergy in cobalt–palladium nanocatalysts for CO oxidation

An Author Correction to this article was published on 21 January 2019

This article has been updated

Abstract

Bimetallic and multi-component catalysts typically exhibit composition-dependent activity and selectivity, and when optimized often outperform single-component catalysts. Here we used ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ and ex situ transmission electron microscopy (TEM) to elucidate the origin of composition dependence observed in the catalytic activities of monodisperse CoPd bimetallic nanocatalysts for CO oxidation. We found that the catalysis process induced a reconstruction of the catalysts, leaving CoOx on the nanoparticle surface. The synergy between Pd and CoOx coexisting on the surface promotes the catalytic activity of the bimetallic catalysts. This synergistic effect can be optimized by tuning the Co/Pd ratios in the nanoparticle synthesis, and it reaches a maximum at compositions near Co0.24Pd0.76, which achieves complete CO conversion at the lowest temperature. Our combined AP-XPS and TEM studies provide direct observation of the surface evolution of the bimetallic nanoparticles under catalytic conditions and show how this evolution correlates with catalytic properties.

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Fig. 1: STEM and EELS elemental mapping of 4.5-nm as-synthesized Co0.24Pd0.76 nanoparticles.
Fig. 2: Catalytic properties of Pd and CoPd nanoparticles.
Fig. 3: AP-XPS measurements on Pd and CoPd nanoparticles under reaction conditions.
Fig. 4: Surface Pd speciation for Pd and CoPd nanoparticles under different conditions.
Fig. 5: Schematic illustration of surface evolution and bimetallic synergy in CoPd alloy nanoparticles with different Co percentage content.
Fig. 6: STEM and EELS elemental mapping of 10-nm Co0.24Pd0.76 nanoparticles after pretreatment.
Fig. 7: The impact of pretreatment temperature on the activity of Co0.52Pd0.48 nanoparticles.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

Change history

  • 21 January 2019

    In the version of this Article originally published, the author Baran Eren was mistakenly affiliated with the Harbin Institute of Technology, China; it has now been corrected to Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

References

  1. 1.

    Dyakonov, A. & Robinson, E. Low-temperature oxidation of CO in smoke: a review. Beitr. Tabakforsch. 22, 88–106 (2006).

    CAS  Google Scholar 

  2. 2.

    van Spronsen, M. A., Frenken, J. W. M. & Groot, I. M. N. Surface science under reaction conditions: CO oxidation on Pt and Pd model catalysts. Chem. Soc. Rev. 46, 4347–4374 (2017).

    Article  Google Scholar 

  3. 3.

    Imbihl, R. Oscillatory reactions on single crystal surfaces. Prog. Surf. Sci. 44, 185–343 (1993).

    CAS  Article  Google Scholar 

  4. 4.

    Rodriguez, J. A. & Goodman, D. W. High-pressure catalytic reactions over single-crystal metal-surfaces. Surf. Sci. Rep. 14, 1–107 (1991).

    CAS  Article  Google Scholar 

  5. 5.

    Freund, H. J., Meijer, G., Scheffler, M., Schlögl, R. & Wolf, M. CO oxidation as a prototypical reaction for heterogeneous processes. Angew. Chem. Int. Ed. 50, 10064–10094 (2011).

    CAS  Article  Google Scholar 

  6. 6.

    Heck, R. M. & Farrauto, R. J. Automobile exhaust catalysts. Appl. Catal. A 221, 443–457 (2001).

    CAS  Article  Google Scholar 

  7. 7.

    Twigg, M. V. Progress and future challenges in controlling automotive exhaust gas emissions. Appl. Catal. B 70, 2–15 (2007).

    CAS  Article  Google Scholar 

  8. 8.

    Nilekar, A. U., Alayoglu, S., Eichhorn, B. & Mavrikakis, M. Preferential CO oxidation in hydrogen: reactivity of core–shell nanoparticles. J. Am. Chem. Soc. 132, 7418–7428 (2010).

    CAS  Article  Google Scholar 

  9. 9.

    Fu, Q. et al. Interface-confined ferrous centers for catalytic oxidation. Science 328, 1141–1144 (2010).

    CAS  Article  Google Scholar 

  10. 10.

    Saavedra, J., Doan, Ha, Pursell, C. J., Grabow, L. C. & Chandler, B. D. The critical role of water at the gold-titania interface in catalytic CO oxidation. Science 345, 1599–1602 (2014).

    CAS  Article  Google Scholar 

  11. 11.

    Wang, Y. G., Yoon, Y., Glezakou, V. A., Li, J. & Rousseau, R. The role of reducible oxide-metal cluster charge transfer in catalytic processes: new insights on the catalytic mechanism of CO oxidation on Au/TiO2 from ab initio molecular dynamics. J. Am. Chem. Soc. 135, 10673–10683 (2013).

    CAS  Article  Google Scholar 

  12. 12.

    Kim, H. Y., Lee, H. M. & Henkelman, G. CO oxidation mechanism on CeO2-supported Au nanoparticles. J. Am. Chem. Soc. 134, 1560–1570 (2012).

    CAS  Article  Google Scholar 

  13. 13.

    Widmann, D. & Behm, R. J. Active oxygen on a Au/TiO2 catalyst: formation, stability, and CO oxidation activity. Angew. Chem. Int. Ed. 50, 10241–10245 (2011).

    CAS  Article  Google Scholar 

  14. 14.

    Haruta, M., Kobayashi, T., Sano, H. & Yamada, N. Novel gold catalysts for the oxidation of carbon monoxide at a temperature far below 0 °C. Chem. Lett. 16, 405–408 (1987).

    Article  Google Scholar 

  15. 15.

    Wang, C., Yin, H., Dai, S. & Sun, S. A general approach to noble metal−metal oxide dumbbell nanoparticles and their catalytic application for CO oxidation. Chem. Mater. 22, 3277–3282 (2010).

    CAS  Article  Google Scholar 

  16. 16.

    An, K. et al. Enhanced CO oxidation rates at the interface of mesoporous oxides and Pt nanoparticles. J. Am. Chem. Soc. 135, 16689–16696 (2013).

    CAS  Article  Google Scholar 

  17. 17.

    Cargnello, M. et al. Control of metal nanocrystal size reveals metal-support interface role for ceria catalysts. Science 341, 771–773 (2013).

    CAS  Article  Google Scholar 

  18. 18.

    Zhu, H. et al. Constructing hierarchical interfaces: TiO2-supported PtFe–FeOx nanowires for room temperature CO oxidation. J. Am. Chem. Soc. 137, 10156–10159 (2015).

    CAS  Article  Google Scholar 

  19. 19.

    Chen, G. et al. Interfacial effects in iron–nickel hydroxide–platinum nanoparticles enhance catalytic oxidation. Science 344, 495–499 (2014).

    CAS  Article  Google Scholar 

  20. 20.

    Shan, S. et al. Atomic-structural synergy for catalytic CO oxidation over palladium-nickel nanoalloys. J. Am. Chem. Soc. 136, 7140–7151 (2014).

    CAS  Article  Google Scholar 

  21. 21.

    Zhan, W. 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 

  22. 22.

    Gilroy, K. D., Ruditskiy, A., Peng, H.-C., Qin, D. & Xia, Y. Bimetallic nanocrystals: syntheses, properties, and applications. Chem. Rev. 116, 10414–10472 (2016).

    CAS  Article  Google Scholar 

  23. 23.

    Yu, W., Porosoff, M. D. & Chen, J. G. Review of Pt-based bimetallic catalysis: from model surfaces to supported catalysts. Chem. Rev. 112, 5780–5817 (2012).

    CAS  Article  Google Scholar 

  24. 24.

    Guo, S., Zhang, S. & Sun, S. Tuning nanoparticle catalysis for the oxygen reduction reaction. Angew. Chem. Int. Ed. 52, 8526–8544 (2013).

    CAS  Article  Google Scholar 

  25. 25.

    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 

  26. 26.

    Tao, F. et al. Evolution of structure and chemistry of bimetallic nanoparticle catalysts under reaction conditions. J. Am. Chem. Soc. 132, 8697–8703 (2010).

    CAS  Article  Google Scholar 

  27. 27.

    Carenco, S. et al. Dealloying of cobalt from CuCo nanoparticles under syngas exposure. J. Phys. Chem. C 117, 6259–6266 (2013).

    CAS  Article  Google Scholar 

  28. 28.

    Ogletree, D. F. et al. A differentially pumped electrostatic lens system for photoemission studies in the millibar range. Rev. Sci. Instrum. 73, 3872 (2002).

    CAS  Article  Google Scholar 

  29. 29.

    Wu, C. H., Weatherup, R. S. & Salmeron, M. B. Probing electrode/electrolyte interfaces in situ by X-ray spectroscopies: old methods, new tricks. Phys. Chem. Chem. Phys. 17, 30229–30239 (2015).

    CAS  Article  Google Scholar 

  30. 30.

    Zheng, H., Meng, Y. S. & Zhu, Y. Frontiers of in situ electron microscopy. MRS Bull. 40, 12–18 (2015).

    Article  Google Scholar 

  31. 31.

    Escudero, C. et al. A reaction cell with sample laser heating for in situ soft X-ray absorption spectroscopy studies under environmental conditions. J. Synch. Radiat. 20, 504–508 (2013).

    CAS  Article  Google Scholar 

  32. 32.

    Heine, C. et al. Ambient-pressure soft X-ray absorption spectroscopy of a catalyst surface in action: closing the pressure gap in the selective n-butane oxidation over vanadyl pyrophosphate. J. Phys. Chem. C 118, 20405–20412 (2014).

    CAS  Article  Google Scholar 

  33. 33.

    Bluhm, H., Ogletree, D. F., Fadley, C. S., Hussain, Z. & Salmeron, M. The premelting of ice studied with photoelectron spectroscopy. J. Phys. Condens. Matter. 14, L227–L233 (2002).

    CAS  Article  Google Scholar 

  34. 34.

    Sun, D., Mazumder, V., Metin, O. & Sun, S. Catalytic hydrolysis of ammonia borane via cobalt palladium nanoparticles. ACS Nano 5, 6458–6464 (2011).

    CAS  Article  Google Scholar 

  35. 35.

    Sun, S. & Murray, C. B. Synthesis of monodisperse cobalt nanocrystals and their assembly into magnetic superlattices (invited). J. Appl. Phys. 85, 4325–4330 (1999).

    CAS  Article  Google Scholar 

  36. 36.

    Zhang, S. et al. Monodisperse core/shell Ni/FePt nanoparticles and their conversion to Ni/Pt to catalyze oxygen reduction. J. Am. Chem. Soc. 136, 15921–15924 (2014).

    CAS  Article  Google Scholar 

  37. 37.

    Ishida, K. & Nishizawa, T. The C–Co (carbon–cobalt) system. J. Phase Equilibria 12, 417–424 (1991).

    CAS  Article  Google Scholar 

  38. 38.

    Toyoshima, R. et al. Active surface oxygen for catalytic CO oxidation on Pd(100) proceeding under near ambient pressure conditions. J. Phys. Chem. Lett. 3, 3182–3187 (2012).

    CAS  Article  Google Scholar 

  39. 39.

    Ketteler, G. et al. In situ spectroscopic study of the oxidation and reduction of Pd(111). J. Am. Chem. Soc. 127, 18269–18273 (2005).

    CAS  Article  Google Scholar 

  40. 40.

    Gries, W. H. Angular intensity modulation in angle-resolved XPS and AES of non-crystalline ultrathin surface layers: the phenomenon and its implications. Surf. Interface Anal. 17, 803–812 (1991).

    CAS  Article  Google Scholar 

  41. 41.

    Kibis, L. S., Titkov, A. I., Stadnichenko, A. I., Koscheev, S. V. & Boronin, A. I. X-ray photoelectron spectroscopy study of Pd oxidation by RF discharge in oxygen. Appl. Surf. Sci. 255, 9248–9254 (2009).

    CAS  Article  Google Scholar 

  42. 42.

    Militello, M. C. Palladium oxide (PdO) by XPS. Surf. Sci. Spectra 3, 395 (1994).

    CAS  Article  Google Scholar 

  43. 43.

    Balmes, O. et al. Reversible formation of a PdCx phase in Pd nanoparticles upon CO and O2 exposure. Phys. Chem. Chem. Phys. 14, 4796 (2012).

    CAS  Article  Google Scholar 

  44. 44.

    Rogal, J., Reuter, K. & Scheffler, M. Oxidation at Pd(100): a first-principles constrained thermodynamics study. Phys. Rev. B 75, 1–11 (2007).

    Article  Google Scholar 

  45. 45.

    Wu, C. H., Eren, B., Bluhm, H. & Salmeron, M. B. Ambient-pressure X-ray photoelectron spectroscopy study of cobalt foil model catalyst under CO, H2, and their mixtures. ACS Catal. 7, 1150–1157 (2017).

    CAS  Article  Google Scholar 

  46. 46.

    Wang, Z. L., Bentley, J. & Evans, N. D. Valence state mapping of cobalt and manganese using near-edge fine structures. Micron 31, 355–362 (2000).

    CAS  Article  Google Scholar 

  47. 47.

    Wang, Z. L., Yin, J. S. & Jiang, Y. D. EELS analysis of cation valence states and oxygen vacancies in magnetic oxides. Micron 31, 571–580 (2000).

    CAS  Article  Google Scholar 

  48. 48.

    Lee, A. F. & Lambert, R. M. Oxidation of Sn overlayers and the structure and stability of Sn oxide films on Pd(111). Phys. Rev. B 58, 4156–4165 (1998).

    CAS  Article  Google Scholar 

  49. 49.

    Batzill, M., Beck, D. E., Jerdev, D. & Koel, B. E. Tin-oxide overlayer formation by oxidation of Pt–Sn(111) surface alloys. J. Vac. Sci. Technol. A 19, 1953 (2001).

    CAS  Article  Google Scholar 

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Acknowledgements

This work was supported by the Office of Basic Energy Sciences of the US Department of Energy under contract no. DE-AC02-05CH11231 through the Chemical Sciences, Geosciences, and Biosciences Division. Funding from the same contract for the ALS and beamline 9.3.2 is also acknowledged. Partial work on CoPd nanoparticles synthesis and characterization were supported by US National Science Foundation (DMR-1809700) and Jeffress Trust Awards Program in Interdisciplinary Research from Thomas F. and Kate Miller Jeffress Memorial Trust. Partial work on electron microscopy carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, was supported by the US Department of Energy, Office of Basic Energy Sciences, under contract no. DE-AC02-98CH10886.

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The project was conceived by C.H.W. and C.L. under the supervision of S.Z, M.B.S. and C.B.M. Catalyst synthesis, basic characterization and catalytic activity measurements were performed by C.L. and S.Z. AP-XPS experiments were conducted by C.H.W., H.-T.F. and B.E. Ex situ TEM and elemental mapping were done by D.S. In situ TEM and EELS measurements were performed by H.X., C.H.W. and S.Z. Ex situ XAS measurements were done by C.H.W. The analysis and interpretation of all spectra (XPS, XAS and EELS) were done by C.H.W. All authors contributed to the writing of the manuscript.

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Correspondence to Sen Zhang or Christopher B. Murray or Miquel B. Salmeron.

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Wu, C.H., Liu, C., Su, D. et al. Bimetallic synergy in cobalt–palladium nanocatalysts for CO oxidation. Nat Catal 2, 78–85 (2019). https://doi.org/10.1038/s41929-018-0190-6

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