Lattice-strain control of the activity in dealloyed core–shell fuel cell catalysts

Article metrics


Electrocatalysis will play a key role in future energy conversion and storage technologies, such as water electrolysers, fuel cells and metal–air batteries. Molecular interactions between chemical reactants and the catalytic surface control the activity and efficiency, and hence need to be optimized; however, generalized experimental strategies to do so are scarce. Here we show how lattice strain can be used experimentally to tune the catalytic activity of dealloyed bimetallic nanoparticles for the oxygen-reduction reaction, a key barrier to the application of fuel cells and metal–air batteries. We demonstrate the core–shell structure of the catalyst and clarify the mechanistic origin of its activity. The platinum-rich shell exhibits compressive strain, which results in a shift of the electronic band structure of platinum and weakening chemisorption of oxygenated species. We combine synthesis, measurements and an understanding of strain from theory to generate a reactivity–strain relationship that provides guidelines for tuning electrocatalytic activity.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Elemental maps and line profiles of Pt–Cu bimetallic nanoparticle precursors and dealloyed active catalysts.
Figure 2: HAADF-STEM images of Pt–Cu bimetallic nanoparticle precursors and dealloyed active catalysts.
Figure 3: AXRD-based structural and phase-composition analysis of Pt–Cu bimetallic nanoparticle precursors and dealloyed nanoparticle catalysts.
Figure 4: A simple structural two-phase core-shell model for the dealloyed nanoparticles and evaluation of their lattice parameters.
Figure 5: Surface-science XAS and XES studies of single-crystal model systems that mimic dealloyed bimetallic core–shell structures.
Figure 6: Experimental and predicted relationships between electrocatalytic ORR activity and lattice strain.


  1. 1

    Stonehart, P. Development of alloy electrocatalysts for phosphoric acid fuel cells (PAFC). Appl. Electrochem. 22, 995–1001 (1992).

  2. 2

    Mukerjee, S. & Srinivasan, S. in Handbook of Fuel Cells—Fundamentals, Technology and Applications Vol. 2. (eds Vielstich, W., Gasteiger, H. A. & Lamm, A.) 502–519 (John Wiley, 2003).

  3. 3

    Gasteiger, H. A., Kocha, S. S., Sompalli, B. & Wagner, F. T. Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs. Appl. Catal. B 56, 9–35 (2005).

  4. 4

    Ertl, G., Knözinger, H., Schueth, F. & Weitkamp, J. Handbook of Heterogeneous Catalysis (Wiley-VCH, 2008).

  5. 5

    Somorjai, G. A. Introduction to Surface Chemistry and Catalysis (Wiley, 1994).

  6. 6

    Sinfelt, J. H. Bimetallic Catalysts: Discoveries, Concepts, and Applications (Wiley, 1983).

  7. 7

    Maroun, F., Ozanam, F., Magnussen, O. M. & Behm, R. J. The role of atomic ensembles in the reactivity of bimetallic electrocatalysts. Science 293, 1811–1814 (2001).

  8. 8

    Rodriguez, J. A. & Goodman, D. W. The nature of the metal–metal bond in bimetallic surfaces. Science 257, 897–903 (1992).

  9. 9

    Rodriguez, J. A. Physical and chemical properties of bimetallic surfaces. Surf. Sci. Rep. 24, 223–287 (1996).

  10. 10

    Greeley, J., Norskov, J. K. & Mavrikakis, M. Electronic structure and catalysis on metal surfaces. Annu. Rev. Phys. Chem. 53, 319–348 (2002).

  11. 11

    Hammer, B. & Nørskov, J. K. Electronic factors determining the reactivity of metal surfaces. Surf. Sci. 343, 211–220 (1995).

  12. 12

    Ruban, A., Hammer, B., Stoltze, P., Skriver, H. L. & Nørskov, J. K. Surface electronic structure and reactivity of transition and noble metals. J. Mol. Catal. A 115, 421–429 (1997).

  13. 13

    Chen, S. et al. Enhanced activity for oxygen reduction reaction on Pt3Co nanoparticles: direct evidence of percolated and sandwich segregation structures. J. Am. Chem. Soc. 130, 13818–13819 (2008).

  14. 14

    Chen, S. et al. Origin of oxygen reduction reaction activity on ‘Pt3Co’ nanoparticles: atomically resolved chemical compositions and structures. J. Phys Chem. C 113, 1109–1125 (2009).

  15. 15

    Chen, M., Kumar, D., Yi, C.-W. & Goodman, D. W. The promotional effect of gold in catalysis by palladium–gold. Science 310, 291–293 (2005).

  16. 16

    Mavrikakis, M., Hammer, B. & Norskov, J. K. Effect of strain on the reactivity of metal surfaces. Phys. Rev. Lett. 81, 2819–2822 (1998).

  17. 17

    Stamenkovic, V. R. et al. Improved oxygen reduction activity on Pt3Ni(111) via increased surface site availability. Science 315, 493–497 (2007).

  18. 18

    Stamenkovic, V. et al. Changing the activity of electrocatalysts for oxygen reduction by tuning the surface electronic structure. Angew. Chem. Int. Ed. 45, 2897–2901 (2006).

  19. 19

    Kibler, L. A., El-Aziz, A. M., Hoyer, R. & Kolb, D. M. Tuning reaction rates by lateral strain in a palladium monolayer. Angew. Chem. Int. Ed. 44, 2080–2084 (2005).

  20. 20

    Zhang, J., Vukmiovic, M. B., Xu, Y., Mavrikakis, M. & Adzic, R. R. Controlling the catalytic activity of platinum-monolayer electrocatalysts for oxygen reduction with different substrates. Angew. Chem. Int. Ed. 44, 2132 (2005).

  21. 21

    Oppenheim, I. C., Trevor, D. J., Chidsey, C. E. D., Trevor, P. L. & Sieradzki, K. In situ scanning tunneling microscopy of corrosion of silver–gold alloys. Science 254, 687–689 (1991).

  22. 22

    Erlebacher, J., Aziz, M. J., Karma, A., Dimitrov, N. & Sieradzki, K. Evolution of nanoporosity in dealloying. Nature 410, 450–453 (2001).

  23. 23

    Renner, F. U. et al. Initial corrosion observed on the atomic scale. Nature 430, 707–710 (2006).

  24. 24

    Srivastava, R., Mani, P., Hahn, N. & Strasser, P. Efficient oxygen reduction fuel cell electrocatalysis on voltammetrically de-alloyed Pt–Cu–Co nanoparticles. Angew. Chem. Int. Ed. 46, 8988–8991 (2007).

  25. 25

    Koh, S. & Strasser, P. Electrocatalysis on bimetallic surfaces: modifying catalytic reactivity for oxygen reduction by voltammetric surface de-alloying. J. Am. Chem. Soc. 129, 12624–12625 (2007).

  26. 26

    Strasser, P. in Handbook of Fuel Cells: Advances in Electrocatalysis, Materials, Diagnostics and Durability Vol. 5 & 6. (eds Vielstich, W., Gasteiger, H. A. & Yokokawa, H.) 30–47 (Wiley, 2009).

  27. 27

    Strasser, P., Koh, S. & Greeley, J. Voltammetric surface dealloying of Pt bimetallic nanoparticles: an experimental and DFT computational analysis. Phys. Chem. Chem. Phys. 10, 3670–3683 (2008).

  28. 28

    Koh, S., Hahn, N., Yu, C. & Strasser, P. Effects of compositions and annealing conditions on the catalytic activities of Pt–Cu Nanoparticle electrocatalysts for PEMFC. J. Electrochem. Soc. 155, B1281–B1288 (2008).

  29. 29

    Vielstich, W., Lamm, A. & Gasteiger, H. (eds) Handbook of Fuel Cells—Fundamentals, Technology, and Applications (Wiley, 2003).

  30. 30

    Janik, M. J., Taylor, C. D. & Neurock, M. First-principles analysis of the initial electroreduction steps of oxygen over Pt(111). J. Electrochem. Soc. 156, B126–B135 (2009).

  31. 31

    Subramanian, P. R. & Laughlin, D. E. in Binary Alloy Phase Diagrams 2nd edn, Vol. 2 (ed. Massalski, T. B.) 1460–1462 (ASM International, 1990).

  32. 32

    Wang, J. X. et al. Oxygen reduction on well defined core shell nanocatalysts: particle size, facet and Pt Shell thickness effects. J. Am. Chem. Soc. 131, 17298–17302 (2009).

  33. 33

    Yu, C., Koh, S., Leisch, J., Toney, M. T. & Strasser, P. Size and composition distribution dynamics of alloy nanoparticle electrocatalysts probed by anomalous small angle X ray scattering (ASAXS). Faraday Discuss. 140, 283–296 (2008).

  34. 34

    Cullity, B. D. & Stock, S. R. Elements of X ray Diffraction 3rd edn (Prentice Hall, 2001).

  35. 35

    Pecharsky, V. & Zavalij, P. Y. Fundamentals of Powder Diffraction and Structural Characterization of Materials (Springer, 2003).

  36. 36

    DeGraef, M. & McHenry, M. E. Structure of Materials: An Introduction to Crystallography, Diffraction, and Symmetry (Cambridge Univ. Press, 2007).

  37. 37

    Klimenkov, M. et al. The structure of Pt-aggregates on a supported thin aluminum oxide film in comparison with unsupported alumina: a transmission electron microscopy study. Surf. Sci. 391, 27–36 (1997).

  38. 38

    Cammarata, R. C. Surface and interface stress effects in thin films. Prog. Surf. Sci. 46, 1–38 (1994).

  39. 39

    Hammer, B. & Nørskov, J. K. Why gold is the noblest of all metals. Nature 376, 238–240 (1995).

  40. 40

    Nilsson, A. et al. The electronic structure effect in heterogeneous catalysis. Catal. Lett. 100, 111–114 (2005).

  41. 41

    Nilsson, A., Pettersson, L. G. M. & Nørskov, J. K. Chemical Bonding at Surfaces and Interfaces (Elsevier, 2008).

  42. 42

    Fusy, J., Meneaucourt, J., Alnot, M., Huguet, C. & Ehrhardt, J. J. Growth and reactivity of evaporated platinum films on Cu(111): a study by AES, RHEED and adsorption of carbon monoxide and xenon. Appl. Surf. Sci. 93, 211–220 (1996).

  43. 43

    Bligaard, T. & Nørskov, J. K. in Chemical Bonding at Surfaces and Interfaces (eds Nilsson, A., Pettersson, L. G. M. & Nørskov, J. K.) Ch. 4 (Elsevier, 2008).

  44. 44

    Lischka, M., Mosch, C. & Gross, A. Tuning catalytic properties of bimetallic surfaces: oxygen adsorption on pseudomorphic Pt/Ru overlayers. Electrochim. Acta 52, 2219–2228 (2007).

  45. 45

    Norskov, J. K. et al. Origin of the overpotential for oxygen reduction at a fuel-cell cathode. J. Phys. Chem. B 108, 17886–17892 (2004).

  46. 46

    Schlapka, A., Lischka, M., Groß, A., Käsberger, U. & Jakob, P. Surface strain versus substrate interaction in heteroepitaxial metal layers: Pt on Ru(0001). Phys. Rev. Lett. 91, 016101 (2003).

  47. 47

    Mani, P., Srivastava, S. & Strasser, P. Dealloyed Pt–Cu Core–Shell Nanoparticle electrocatalysts for use in PEM fuel cell cathodes. J. Phys. Chem. C 112, 2770–2778 (2008).

  48. 48

    Hammer, B., Hansen, L. B. & Nørskov, J. K. Improved adsorption energetics within density-functional theory using revised Perdew–Burke–Ernzerhof functionals. Phys. Rev. B 59, 7413–7421 (1999).

  49. 49

    Yeh, J. J. & Lindau, I. Atomic Data and Nuclear Data Tables 32, 1–155 (1985).

Download references


This project was supported by the Department of Energy, Office of Basic Energy Sciences, under the auspices of the President's Hydrogen Fuel Initiative. Acknowledgment is also made to the National Science Foundation (grant #729722) for partial support of this research. P.S. acknowledges support from the Cluster of Excellence in Catalysis (UNICAT) funded by the German National Science Foundation (Deutsche Forschungsgemeinschaft) and managed by the Technical University Berlin, Germany. Portions of this research were carried out at the Stanford Synchrotron Radiation Lightsource, a national user facility operated by Stanford University on behalf of the US Department of Energy, Office of Basic Energy Sciences. Use of the Center for Nanoscale Materials was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357. We acknowledge computer time at the Laboratory Computing Resource Center (LCRC) at Argonne National Laboratory, the National Energy Research Scientific Computing Center (NERSC) and the EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Microscopy research supported by ORNL's SHaRE User Program, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The authors thank L. Pettersson for reading the manuscript.

Author information

P.S., M.F.T., J.G. and A.N. designed the research and co-wrote the paper, S.K., T.A., K.M., C.Y., Z.L., S.K., D.N. and H.O. performed the experiments and analysed the data, and J.G. performed the theoretical calculations.

Correspondence to Peter Strasser.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Strasser, P., Koh, S., Anniyev, T. et al. Lattice-strain control of the activity in dealloyed core–shell fuel cell catalysts. Nature Chem 2, 454–460 (2010) doi:10.1038/nchem.623

Download citation

Further reading