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.

Dynamic charge and oxidation state of Pt/CeO2 single-atom catalysts

Abstract

The catalytic activity of metals supported on oxides depends on their charge and oxidation state. Yet, the determination of the degree of charge transfer at the interface remains elusive. Here, by combining density functional theory and first-principles molecular dynamics on Pt single atoms deposited on the CeO2 (100) surface, we show that the common representation of a static metal charge is oversimplified. Instead, we identify several well-defined charge states that are dynamically interconnected and thus coexist. The origin of this new class of strong metal–support interactions is the relative position of the Ce(4f) levels with respect to those of the noble metal, allowing electron injection to (or recovery from) the support. This process is phonon-assisted, as the Ce(4f) levels adjust by surface atom displacement, and appears for other metals (Ni) and supports (TiO2). Our dynamic model explains the unique reactivity found for activated single Pt atoms on ceria able to perform CO oxidation, meeting the Department of Energy 150 °C challenge for emissions.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Static PBE + U Pt adsorption energies on CeO2 (100).
Fig. 2: BOMD simulations of the Pt–nO systems.
Fig. 3: DOS decomposition for the Pt–2O systems with different oxidation states.
Fig. 4: CO oxidation on Pt–nO structures.

Data availability

The datasets generated during the current study are available in the ioChem-BD database55 (https://doi.org/10.19061/iochem-bd-1-78).

References

  1. 1.

    Stair, P. C. Metal-oxide interfaces: where the action is. Nat. Chem. 3, 345–346 (2011).

    Article  CAS  Google Scholar 

  2. 2.

    Lykhach, Y. et al. Counting electrons on supported nanoparticles. Nat. Mater. 15, 284–288 (2015).

    Article  CAS  Google Scholar 

  3. 3.

    Schneider, W.-D., Heyde, M. & Freund, H.-J. Charge control in model catalysis: the decisive role of the oxide–nanoparticle interface. Chemistry 24, 2317–2327 (2018).

    Article  CAS  Google Scholar 

  4. 4.

    Kumar, G. et al. Evaluating differences in the active-site electronics of supported Au nanoparticle catalysts using hammett and DFT studies. Nat. Chem. 10, 268–274 (2018).

    Article  CAS  Google Scholar 

  5. 5.

    Campbell, C. T. Catalyst–support interactions: electronic perturbations. Nat. Chem. 4, 597–598 (2012).

    Article  CAS  Google Scholar 

  6. 6.

    Tauster, S. J., Fung, S. C. & Garten, R. L. Strong metal–support interactions. Group 8 noble metals supported on titanium dioxide. J. Am. Chem. Soc. 100, 170–175 (1978).

    Article  CAS  Google Scholar 

  7. 7.

    Rodríguez, J. A. et al. Activity of CeOx and TiOx nanoparticles grown on Au(111) in the water–gas shift reaction. Science 318, 1757–1760 (2007).

    Article  CAS  Google Scholar 

  8. 8.

    Divins, N. J., Angurell, I., Escudero, C., Perez-Dieste, V. & Llorca, J. Influence of the support on surface rearrangements of bimetallic nanoparticles in real catalysts. Science 346, 620–623 (2014).

    Article  CAS  Google Scholar 

  9. 9.

    Fu, Q., Saltsburg, H. & Flytzani-Stephanopoulos, M. Active nonmetallic Au and Pt species on ceria-based water–gas shift catalysts. Science 301, 935–938 (2003).

    Article  CAS  Google Scholar 

  10. 10.

    Qiao, B. et al. Single-atom catalysis of CO oxidation using Pt1/FeOx. Nat. Chem. 3, 634–641 (2011).

    Article  CAS  Google Scholar 

  11. 11.

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

    Article  CAS  Google Scholar 

  12. 12.

    Therrien, A. J. et al. An atomic-scale view of single-site Pt catalysis for low-temperature CO oxidation. Nat. Catal. 1, 192–198 (2018).

    Article  CAS  Google Scholar 

  13. 13.

    Nagai, Y. et al. In situ redispersion of platinum autoexhaust catalysts: an on-line approach to increasing catalyst lifetimes? Angew. Chem. Int. Ed. 47, 9303–9306 (2008).

    Article  CAS  Google Scholar 

  14. 14.

    Gänzler, A. M. et al. Tuning the structure of platinum particles on ceria in situ for enhancing the catalytic performance of exhaust gas catalysts. Angew. Chem. Int. Ed. 56, 13078–13082 (2017).

    Article  CAS  Google Scholar 

  15. 15.

    Nie, L. et al. Activation of surface lattice oxygen in single-atom Pt/CeO2 for low-temperature CO oxidation. Science 358, 1419–1423 (2017).

    Article  CAS  Google Scholar 

  16. 16.

    Lin, J. et al. Remarkable performance of Ir1/FeOx single-atom catalyst in water gas shift reaction. J. Am. Chem. Soc. 135, 15314–15317 (2013).

    Article  CAS  Google Scholar 

  17. 17.

    Liu, P. et al. Photochemical route for synthesizing atomically dispersed palladium catalysts. Science 352, 797–800 (2016).

    Article  CAS  Google Scholar 

  18. 18.

    Wei, H. et al. FeOx-supported platinum single-atom and pseudo-single-atom catalysts for chemoselective hydrogenation of functionalized nitroarenes. Nat. Commun. 5, 5634 (2014).

    Article  CAS  Google Scholar 

  19. 19.

    McCabe, R. W. & Trovarelli, A. Forty years of catalysis by ceria: a success story. Appl. Catal. B Environ. 197, 1 (2016).

    Article  CAS  Google Scholar 

  20. 20.

    Trovarelli, A. & Llorca, J. Ceria catalysts at nanoscale: how do crystal shapes shape catalysis? ACS Catal. 7, 4716–4735 (2017).

    Article  CAS  Google Scholar 

  21. 21.

    Jones, J. et al. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping. Science 353, 150–154 (2016).

    Article  CAS  Google Scholar 

  22. 22.

    Kunwar, D. et al. Stabilizing high metal loadings of thermally stable platinum single atoms on an industrial catalyst support. ACS Catal. 9, 3978–3990 (2019).

    Article  CAS  Google Scholar 

  23. 23.

    Zhou, G., Li, P., Ma, Q., Tian, Z. & Liu, Y. Density functional theory plus Hubbard U study of the segregation of Pt to the CeO2−x grain boundary. Nano Lett. 18, 1668–1677 (2018).

    Article  CAS  Google Scholar 

  24. 24.

    Dvoǐák, F. et al. Creating single-atom Pt-ceria catalysts by surface step decoration. Nat. Commun. 7, 10801–10808 (2016).

    Article  CAS  Google Scholar 

  25. 25.

    Bruix, A. et al. Maximum noble-metal efficiency in catalytic materials: atomically dispersed surface platinum. Angew. Chem. Int. Ed. 53, 10525–10530 (2014).

    Article  CAS  Google Scholar 

  26. 26.

    Zammit, M. et al. Future Sutomotive Aftertreatment Solutions: the 150°C Challenge Workshop Report Technical Report (Pacific Northwest National Laboratory, 2013).

  27. 27.

    Farmer, J. A. & Campbell, C. T. Ceria maintains smaller metal catalyst particles by strong metal-support bonding. Science 329, 933–936 (2010).

    Article  CAS  Google Scholar 

  28. 28.

    Wu, T. et al. Investigation of the redispersion of Pt nanoparticles on polyhedral ceria nanoparticles. J. Phys. Chem. Lett. 5, 2479–2483 (2014).

    Article  CAS  Google Scholar 

  29. 29.

    Pereira Hernandez, X. I. et al. Tuning Pt–CeO2 interactions by high-temperature vapor-phase synthesis for improved reducibility of lattice oxygen. Nat. Commun. 10, 1358 (2019).

    Article  CAS  Google Scholar 

  30. 30.

    Neitzel, A. et al. Atomically dispersed Pd, Ni, and Pt species in ceria-based catalysts: principal differences in stability and reactivity. J. Phys. Chem. C 120, 9852–9862 (2016).

    Article  CAS  Google Scholar 

  31. 31.

    Plata, J., Márquez, A. M. & Sanz, J. F. Electron mobility via polaron hopping in bulk ceria: a first-principles study. J. Phys. Chem. C 117, 14502–14509 (2013).

    Article  CAS  Google Scholar 

  32. 32.

    Reticcioli, M. et al. Polaron-driven surface reconstructions. Phys. Rev. X 7, 031053 (2017).

    Google Scholar 

  33. 33.

    Capdevila-Cortada, M. & López, N. Entropic contributions enhance polarity compensation for CeO2 (100) surfaces. Nat. Mater. 16, 328–334 (2017).

    Article  CAS  Google Scholar 

  34. 34.

    Walsh, A., Sokol, A. A., Buckeridge, J., Scanlon, D. O. & Catlow, C. R. A. Oxidation states and ionicity. Nat. Mater. 17, 958–964 (2018).

    Article  CAS  Google Scholar 

  35. 35.

    Lykhach, Y. et al. Reactivity of atomically dispersed Pt2+ species towards H2: model Pt–CeO2 fuel cell catalyst. Phys. Chem. Chem. Phys. 18, 7672–7679 (2016).

    Article  CAS  Google Scholar 

  36. 36.

    Greenwood, N. N. & Earnshaw, A. Chemistry of the Elements. 2nd edn, (Elsevier: 1997).

  37. 37.

    Ouyang, R., Liu, J.-X. & Li, W.-X. Atomistic theory of Ostwald ripening and disintegration of supported metal particles under reaction conditions. J. Am. Chem. Soc. 135, 1760–1771 (2013).

    Article  CAS  Google Scholar 

  38. 38.

    Datye, A. K. & Wang, Y. Atom trapping: a novel approach to generate thermally stable and regenerable single-atom catalysts. Natl Sci. Rev. 5, 630–632 (2018).

    Article  Google Scholar 

  39. 39.

    Kramida, A., Ralchenko, Y., Reader, J. & Team, N. A. Atomic Spectra Database (version 5.5.6) (National Institute of Standards and Technology, 2018); https://physics.nist.gov/cgi-bin/ASD/ie.pl

  40. 40.

    Capdevila-Cortada, M., García-Melchor, M. & López, N. Unraveling the structure sensitivity in methanol conversion on CeO2: a DFT + U study. J. Catal. 327, 58–64 (2015).

    Article  CAS  Google Scholar 

  41. 41.

    Andersin, J., Nevalaita, J., Honkala, K. & Häkkinen, H. The redox chemistry of gold with high-valence doped calcium oxide. Angew. Chem. Int. Ed. 52, 1424–1427 (2013).

    Article  CAS  Google Scholar 

  42. 42.

    Kowalski, P. M., Camellone, M. F., Nair, N. N., Meyer, B. & Marx, D. Charge localization dynamics induced by oxygen vacancies on the TiO2 (110) surface. Phys. Rev. Lett. 105, 146405 (2010).

    Article  CAS  Google Scholar 

  43. 43.

    Pilger, F. et al. Size control of Pt clusters on CeO2 nanoparticles via an incorporation–segregation mechanism and study of segregation kinetics. ACS Catal. 6, 3688–3699 (2016).

    Article  CAS  Google Scholar 

  44. 44.

    DeRita, L. et al. Structural evolution of atomically dispersed Pt catalysts dictates reactivity. Nat. Mater. 18, 746–751 (2019).

    Article  CAS  Google Scholar 

  45. 45.

    Ha, M.-A., Baxter, E. T., Cass, A. C., Anderson, S. L. & Alexandrova, A. N. Boron switch for selectivity of catalytic dehydrogenation on size-selected Pt clusters on Al2O3. J. Am. Chem. Soc. 139, 11568–11575 (2017).

    Article  CAS  Google Scholar 

  46. 46.

    Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).

    Article  CAS  Google Scholar 

  47. 47.

    Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

    Article  Google Scholar 

  48. 48.

    Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

    Article  CAS  Google Scholar 

  49. 49.

    Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    Article  CAS  Google Scholar 

  50. 50.

    Dudarev, S. L., Botton, G. A., Savrasov, S. Y., Humphreys, C. J. & Sutton, A. P. Electron-energy-loss spectra and the structural stability of nickel oxide: an LSDA + U study. Phys. Rev. B 57, 1505–1509 (1998).

    Article  CAS  Google Scholar 

  51. 51.

    Fabris, S., de Gironcoli, S., Baroni, S., Vicario, G. & Balducci, G. Taming multiple valency with density functionals: a case study of defective ceria. Phys. Rev. B 71, 041102 (2005).

    Article  CAS  Google Scholar 

  52. 52.

    Naghavi, S. S. et al. Giant onsite electronic entropy enhances the performance of ceria for water splitting. Nat. Commun. 8, 285–291 (2017).

    Article  CAS  Google Scholar 

  53. 53.

    Penschke, C. & Paier, J. Reduction and oxidation of Au adatoms on the CeO2(111) surface—DFT + U versus hybrid functionals. Phys. Chem. Chem. Phys. 19, 12546–12558 (2017).

    Article  CAS  Google Scholar 

  54. 54.

    Hoover, W. G. Canonical dynamics: equilibrium phase–space distributions. Phys. Rev. A 31, 1695–1697 (1985).

    Article  CAS  Google Scholar 

  55. 55.

    Álvarez-Moreno, M. et al. Managing the computational chemistry big data problem: the ioChem-BD platform. J. Chem. Inf. Model. 55, 95–103 (2015).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This research has been supported by the Ministerio de Economía y Competitividad (CTQ2015-68770-R). The authors acknowledge BSC-RES and BIFI for providing generous computational resources. We also thank A. Bruix for critically reading the manuscript, and T. Schäfer for help with the random phase approximation (RPA) methodology.

Author information

Affiliations

Authors

Contributions

N.D. performed the calculations. N.D., M.C.-C. and N.L. analysed the data and prepared the manuscript.

Corresponding author

Correspondence to Núria López.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Notes 1–6, Figs. 1–14, Tables 1–9, video captions 1–4 and references 1–5

Supplementary Video 1

Molecular dynamics simulation of polaron-induced electron transfer between a single Pt atom and its support—a (2 × 2) CeO2 supercell with a 2O termination.

Supplementary Video 2

Molecular dynamics simulation of polaron-induced electron transfer between a single Pt atom and its support—a (2 × 2) CeO2 supercell with a 3O termination.

Supplementary Video 3

Molecular dynamics simulation of polaron-induced electron transfer between a single Pt atom and its support—a (2 × 2) CeO2 supercell with a 4O termination.

Supplementary Video 4

Molecular dynamics simulation of polaron-induced electron transfer between a single Pt atom and its support—a (3 × 3) CeO2 supercell with a 2O termination.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Daelman, N., Capdevila-Cortada, M. & López, N. Dynamic charge and oxidation state of Pt/CeO2 single-atom catalysts. Nat. Mater. 18, 1215–1221 (2019). https://doi.org/10.1038/s41563-019-0444-y

Download citation

Further reading

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