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High electrochemical activity of the oxide phase in model ceria–Pt and ceria–Ni composite anodes

Abstract

Fuel cells, and in particular solid-oxide fuel cells (SOFCs), enable high-efficiency conversion of chemical fuels into useful electrical energy and, as such, are expected to play a major role in a sustainable-energy future. A key step in the fuel-cell energy-conversion process is the electro-oxidation of the fuel at the anode. There has been increasing evidence in recent years that the presence of CeO2-based oxides (ceria) in the anodes of SOFCs with oxygen-ion-conducting electrolytes significantly lowers the activation overpotential for hydrogen oxidation. Most of these studies, however, employ porous, composite electrode structures with ill-defined geometry and uncontrolled interfacial properties. Accordingly, the means by which electrocatalysis is enhanced has remained unclear. Here we demonstrate unambiguously, through the use of ceria–metal structures with well-defined geometries and interfaces, that the near-equilibrium H2 oxidation reaction pathway is dominated by electrocatalysis at the oxide/gas interface with minimal contributions from the oxide/metal/gas triple-phase boundaries, even for structures with reaction-site densities approaching those of commercial SOFCs. This insight points towards ceria nanostructuring as a route to enhanced activity, rather than the traditional paradigm of metal-catalyst nanostructuring.

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Figure 1: Patterned metal on thin-film ceria as a model system to study competing electrochemical reactions.
Figure 2: Typical impedance spectra obtained from ceria–metal patterned electrodes presented in Nyquist form.
Figure 3: Electrochemical activity in ceria–metal model electrodes.
Figure 4: Comparison of the electrochemical activity of ceria with and without metal 3PBs.
Figure 5: Microstructural and electrochemical characteristics of a porous, columnar SDC electrode with a feature size of ~200 nm fabricated by PLD.

References

  1. Jiang, S. P. & Chan, S. H. A review of anode materials development in solid oxide fuel cells. J. Mater. Sci. 39, 4405–4439 (2004).

    CAS  Article  Google Scholar 

  2. Sholklapper, T. Z., Kurokawa, H., Jacobson, C. P., Visco, S. J. & De Jonghe, L. C. Nanostructured solid oxide fuel cell electrodes. Nano Lett. 7, 2136–2141 (2007).

    CAS  Article  Google Scholar 

  3. Kurokawa, H., Sholklapper, T. Z., Jacobson, C. P., De Jonghe, L. C. & Visco, S. J. Ceria nanocoating for sulfur tolerant Ni-based anodes of solid oxide fuel cells. Electrochem. Solid State 10, B135–B138 (2007).

    CAS  Article  Google Scholar 

  4. Gorte, R. J. & Vohs, J. M. Nanostructured anodes for solid oxide fuel cells. Curr. Opin. Colloid Interface 14, 236–244 (2009).

    CAS  Article  Google Scholar 

  5. Gross, M. D., Vohs, J. M. & Gorte, R. J. A strategy for achieving high performance with SOFC ceramic anodes. Electrochem. Solid State 10, B65–B69 (2007).

    CAS  Article  Google Scholar 

  6. Marina, O. A., Bagger, C., Primdahl, S. & Mogensen, M. A solid oxide fuel cell with a gadolinia-doped ceria anode: Preparation and performance. Solid State Ion. 123, 199–208 (1999).

    CAS  Article  Google Scholar 

  7. Tsai, T. & Barnett, S. A. Increased solid-oxide fuel cell power density using interfacial ceria layer. Solid State Ion. 98, 191–196 (1997).

    CAS  Article  Google Scholar 

  8. Tsai, T. & Barnett, S. A. Effect of mixed-conducting interfacial layers on solid oxide fuel cell anode performance. J. Electrochem. Soc. 145, 1696–1701 (1998).

    CAS  Article  Google Scholar 

  9. Murray, E. P., Tsai, T. & Barnett, S. A. A direct-methane fuel cell with a ceria-based anode. Nature 400, 649–651 (1999).

    CAS  Article  Google Scholar 

  10. Park, S., Vohs, J. M. & Gorte, R. J. Direct oxidation of hydrocarbons in solid-oxide fuel cell. Nature 404, 265–267 (2000).

    CAS  Article  Google Scholar 

  11. Fu, Q., Weber, A. & Flytzani-Stephanopoulos, M. Nanostructured Au–CeO2 catalysts for low-temperature water-gas shift. Catal. Lett. 77, 87–95 (2001).

    CAS  Article  Google Scholar 

  12. Park, J. B. et al. High catalytic activity of Au/CeOx/TiO2(110) controlled by the nature of the mixed-metal oxide at the nanometer level. Proc. Natl Acad. Sci. USA 163, 4975–4980 (2009).

    Article  Google Scholar 

  13. Rodriguez, 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).

    CAS  Article  Google Scholar 

  14. Trovarelli, A. Catalytic properties of ceria and CeO2-containing materials. Catal. Rev. Sci. Eng. 38, 439–520 (1996).

    CAS  Article  Google Scholar 

  15. Eguchi, K., Setoguchi, T., Inoue, T. & Arai, H. Electrical properties of ceria-based oxides and their application to solid oxide fuel cells. Solid State Ion. 52, 165–172 (1992).

    CAS  Article  Google Scholar 

  16. Setoguchi, T., Okamoto, K., Eguchi, K. & Arai, H. Effects of anode material and fuel on anodic reaction of solid oxide fuel cells. J. Electrochem. Soc. 139, 2875–2880 (1992).

    CAS  Article  Google Scholar 

  17. Ruiz-Trejo, E. & Maier, J. Electronic transport in single crystals of Gd-doped ceria. J. Electrochem. Soc. 154, 583–587 (2007).

    Article  Google Scholar 

  18. Tuller, H. L. & Nowick, A. S. Small polaron electron-transport in reduced CeO2 single-crystals. J. Phys. Chem. Solids 38, 859–867 (1977).

    CAS  Article  Google Scholar 

  19. Lai, W. & Haile, S. M. Impedance spectroscopy as a tool for chemical and electrochemical analysis of mixed conductors: A case study of ceria. J. Am. Ceram. Soc. 88, 2979–2997 (2005).

    CAS  Article  Google Scholar 

  20. Lu, C., Worrell, W. L., Vohs, J. M. & Gorte, R. J. A comparison of Cu-ceria-SDC and Au-ceria-SDC composites for SOFC anodes. J. Electrochem. Soc. 150, A1357–A1359 (2003).

    CAS  Article  Google Scholar 

  21. Lai, W. Impedance Spectroscopy as a Tool for the Electrochemical Study of Mixed Conducting Ceria. PhD thesis, California Inst. Technology, (2006).

  22. Chueh, W. C., Lai, W. & Haile, S. M. Electrochemical behavior of ceria with selected metal electrodes. Solid State Ion. 179, 1036–1041 (2008).

    CAS  Article  Google Scholar 

  23. Ciucci, F., Chueh, W. C., Goodwin, D. G. & Haile, S. M. Surface reaction and transport in mixed conductors with electrochemically-active surfaces: A 2-D numerical study of ceria. Phys. Chem. Chem. Phys. 13, 2121–2135 (2011).

    CAS  Article  Google Scholar 

  24. DeCaluwe, S. C. et al. In situ characterization of ceria oxidation states in high-temperature electrochemical cells with ambient pressure XPS. J. Phys. Chem. C 114, 19853–19861 (2010).

    CAS  Article  Google Scholar 

  25. Nakamura, T. et al. Determination of the reaction zone in gadolinia-doped ceria anode for solid oxide fuel cell. J. Electrochem. Soc. 155, 1244–1250 (2008).

    Article  Google Scholar 

  26. Nakamura, T. et al. Electrochemical behaviors of mixed conducting oxide anodes for solid oxide fuel cells. J. Electrochem. Soc. 155, 563–569 (2008).

    Article  Google Scholar 

  27. Zhang, C. J. et al. Measuring fundamental properties in operating solid oxide electrochemical cells by using in situ X-ray photoelectron spectroscopy. Nature Mater. 9, 944–949 (2010).

    CAS  Article  Google Scholar 

  28. Chen, M., Kim, B. H., Xu, Q., Ahn, B. G. & Huang, D. P. Effect of Ni content on the microstructure and electrochemical properties of Ni-SDC anodes for IT-SOFC. Solid State Ion. 181, 1119–1124 (2010).

    CAS  Article  Google Scholar 

  29. McIntosh, S., Vohs, J. M. & Gorte, R. J. Effect of precious-metal dopants on SOFC anodes for direct utilization of hydrocarbons. Electrochem. Solid State 6, A240–A243 (2003).

    CAS  Article  Google Scholar 

  30. Uchida, H., Suzuki, S. & Watanabe, M. High performance electrode for medium-temperature solid oxide fuel cells: Mixed conducting ceria-based anode with highly dispersed Ni electrocatalysts. Electrochem. Solid State 6, A174–A177 (2003).

    CAS  Article  Google Scholar 

  31. Uchida, H., Osuga, T. & Watanabe, M. High-performance electrode for medium-temperature solid oxide fuel cells: Control of microstructure of ceria-based anodes with highly dispersed ruthenium electrocatalysts. J. Electrochem. Soc. 146, 1677–1682 (1999).

    CAS  Article  Google Scholar 

  32. Bessler, W. G. et al. Model anodes and anode models for understanding the mechanism of hydrogen oxidation in solid oxide fuel cells. Phys. Chem. Chem. Phys. 12, 13888–13903 (2010).

    CAS  Google Scholar 

  33. Bieberle, A., Meier, L. P. & Gauckler, L. J. The electrochemistry of Ni pattern anodes used as solid oxide fuel cell model electrodes. J. Electrochem. Soc. 148, A646–A656 (2001).

    CAS  Article  Google Scholar 

  34. Mizusaki, J., Amano, K., Yamauchi, S. & Fueki, K. Electrode-reaction at Pt,O2(g)/stabilized zirconia interfaces. Part II. Electrochemical measurements & analysis. Solid State Ion. 22, 323–330 (1987).

    CAS  Article  Google Scholar 

  35. Mizusaki, J. et al. Kinetic studies of the reaction at the nickel pattern electrode on YSZ in H2–H2O atmospheres. Solid State Ion. 70, 52–58 (1994).

    Article  Google Scholar 

  36. Wilson, J. R. et al. Three-dimensional reconstruction of a solid-oxide fuel-cell anode. Nature Mater. 5, 541–544 (2006).

    CAS  Article  Google Scholar 

  37. Brauer, G. & Gradinger, H. Uber heterotype Mischphasen bei Seltenerdoxyden. I. Z. Anorg. Allg. Chem. 276, 209–226 (1954).

    CAS  Article  Google Scholar 

  38. Godickemeier, M. & Gauckler, L. J. Engineering of solid oxide fuel cells with ceria-based electrolytes. J. Electrochem. Soc. 145, 414–421 (1998).

    CAS  Article  Google Scholar 

  39. Mogensen, M., Sammes, N. M. & Tompsett, G. A. Physical, chemical and electrochemical properties of pure an doped ceria. Solid State Ion. 129, 63–94 (2000).

    CAS  Article  Google Scholar 

  40. Chueh, W. C. & Haile, S. M. Electrochemical studies of capacitance in cerium oxide thin films and its relationship to anionic and electronic defect densities. Phys. Chem. Chem. Phys. 11, 8144–8148 (2009).

    CAS  Article  Google Scholar 

  41. Kobayashi, T., Wang, S., Dokiya, M., Tagawa, H. & Hashimoto, T. Oxygen nonstoichiometry of Ce1−ySmyO2−0.5y−x (y=0.1, 0.2). Solid State Ion. 126, 349–357 (1999).

    CAS  Article  Google Scholar 

  42. Chueh, W. C. Electrochemical and Thermochemical Behavior of C e O2−x. PhD thesis, California Inst. Technology (2011).

  43. Huang, Y-H., Dass, R. I., Xing, Z-L. & Goodenough, J. B. Double perovskite as anode materials for solid-oxide fuel cells. Science 312, 254–257 (2006).

    CAS  Article  Google Scholar 

  44. Tao, S. & Irvine, J. T. S. A redox-stable efficient anode for solid-oxide fuel cells. Nature Mater. 2, 320–323 (2003).

    CAS  Article  Google Scholar 

  45. Zha, S., Rauch, W. & Liu, M. Ni–Ce0.9Gd0.1O1.95 anode for GDC electrolyte-based low-temperature SOFCs. Solid State Ion. 166, 241–250 (2004).

    CAS  Article  Google Scholar 

  46. Muecke, U. P. et al. Electrochemical performance of nanocrystalline nickel/gadolinia-doped ceria thin film anodes for solid oxide fuel cells. Solid State Ion. 178, 1762–1768 (2008).

    CAS  Article  Google Scholar 

  47. Primdahl, S. & Mogensen, M. Mixed conductor anodes: Ni as electrocatalyst for hydrogen conversion. Solid State Ion. 152–153, 597–608 (2002).

    Article  Google Scholar 

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Acknowledgements

This work was supported in part by the Stanford Global Climate & Energy Project and by the National Science Foundation under contract number DMR-0604004. Additional support was provided by the NSF through the Caltech Center for the Science and Engineering of Materials, a Materials Research Science and Engineering Center (DMR-052056). W.C.C. was also supported by an appointment to the Sandia National Laboratories Truman Fellowship in National Security Science and Engineering, sponsored by Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) as Operator of Sandia National Laboratories under its US Department of Energy Contract No. DE-AC04-94AL85000. The authors also acknowledge C. M. Garland and D. A. Boyd of Caltech and M. W. Clift of Sandia for their assistance with analytical measurements, K. L. Gu of Caltech for sample fabrication, F. Ciucci of University of Heidelberg for numerical simulations and D. G. Goodwin and E. C. Brown of Caltech and F. El Gabaly and A. H. McDaniel of Sandia for valuable discussions. The Evans Analytical Group carried out focused ion beam imaging, and for that effort the authors are particularly grateful to H. Deng.

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W.C.C. designed the experiment, fabricated samples and carried out analytical and electrochemical characterizations. Y.H. developed the fabrication methodology for dense electrochemical cells and carried out the sample preparations and characterizations. W.J. fabricated and characterized porous electrochemical cells. S.M.H. guided and supervised the work.

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Correspondence to Sossina M. Haile.

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Chueh, W., Hao, Y., Jung, W. et al. High electrochemical activity of the oxide phase in model ceria–Pt and ceria–Ni composite anodes. Nature Mater 11, 155–161 (2012). https://doi.org/10.1038/nmat3184

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