Cu/CeO2 catalysts are highly active for the low-temperature water–gas shift—a core reaction in syngas chemistry for tuning the H2/CO/CO2 proportions in feed streams—but the direct identification and quantitative description of the active sites remain challenging. Here we report that the active copper clusters consist of a bottom layer of mainly Cu+ atoms bonded on the oxygen vacancies (Ov) of ceria, in a form of Cu+–Ov–Ce3+, and a top layer of Cu0 atoms coordinated with the underlying Cu+ atoms. This atomic structure model is based on directly observing copper clusters dispersed on ceria by a combination of scanning transmission electron microscopy and electron energy loss spectroscopy, in situ probing of the interfacial copper–ceria bonding environment by infrared spectroscopy and rationalization by density functional theory calculations. These results, together with reaction kinetics, reveal that the reaction occurs at the copper–ceria interfacial perimeter via a site cooperation mechanism: the Cu+ site chemically adsorbs CO whereas the neighbouring Ov–Ce3+ site dissociatively activates H2O.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

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.

Additional information

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


  1. 1.

    Li, Y., Fu, Q. & Flytzani-Stephanopoulos, M. Low-temperature water–gas shift reaction over Cu- and Ni-loaded cerium oxide catalysts. Appl. Catal. B 27, 179–191 (2000).

  2. 2.

    Wang, X. et al. In situ studies of the active sites for the water gas shift reaction over Cu−CeO2 catalysts: complex interaction between metallic copper and oxygen vacancies of ceria. J. Phys. Chem. B 110, 428–434 (2006).

  3. 3.

    Gawade, P., Mirkelamoglu, B. & Ozkan, U. S. The role of support morphology and impregnation medium on the water gas shift activity of ceria-supported copper catalysts. J. Phys. Chem. C 114, 18173–18181 (2010).

  4. 4.

    Si, R. et al. Structure sensitivity of the low-temperature water–gas shift reaction on Cu–CeO2 catalysts. Catal. Today 180, 68–80 (2012).

  5. 5.

    Yao, S. et al. Morphological effects of the nanostructured ceria support on the activity and stability of CuO/CeO2 catalysts for the water–gas shift reaction. Phys. Chem. Chem. Phys. 16, 17183–17195 (2014).

  6. 6.

    Ren, Z., Peng, F., Li, J., Liang, X. & Chen, B. Morphology-dependent properties of Cu/CeO2 catalysts for the water–gas shift reaction. Catalysts 7, 48–60 (2017).

  7. 7.

    Chen, C. et al. Cu/CeO2 catalyst for water–gas shift reaction: effect of CeO2 pretreatment. ChemPhysChem 19, 1448–1455 (2018).

  8. 8.

    Shen, W., Ichihashi, Y. & Matsumura, Y. Low-temperature methanol synthesis from carbon monoxide and hydrogen over ceria supported copper catalyst. Appl. Catal. A 282, 221–226 (2005).

  9. 9.

    Yang, R. et al. Performance of Cu-based catalysts in low-temperature methanol synthesis. Adv. Mater. Res. 1004–1005, 1623–1626 (2014).

  10. 10.

    Graciani, J. et al. Highly active copper–ceria and copper–ceria–titania catalysts for methanol synthesis from CO2. Science 345, 546–551 (2014).

  11. 11.

    Rodriguez, J. A. et al. Hydrogenation of CO2 to methanol: importance of metal–oxide and metal–carbide interfaces in the activation of CO2. ACS Catal. 5, 6696–6706 (2015).

  12. 12.

    Ouyang, B., Tan, W. & Li, B. Morphology effect of nanostructure ceria on the Cu/CeO2 catalysts for synthesis of methanol from CO2 hydrogenation. Catal. Commun. 95, 36–39 (2017).

  13. 13.

    van de Water, L. G. A., Wilkinson, S. K., Smith, R. A. P. & Watson, M. J. Understanding methanol synthesis from CO/H2 feeds over Cu/CeO2 catalysts. J. Catal. 364, 57–68 (2018).

  14. 14.

    Konsolakis, M. The role of copper–ceria interactions in catalysis science: recent theoretical and experimental advances. Appl. Catal. B 198, 49–66 (2016).

  15. 15.

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

  16. 16.

    Rodriguez, J. A., Grinter, D. C., Liu, Z., Palomino, R. M. & Senanayake, S. D. Ceria-based model catalysts: fundamental studies on the importance of the metal–ceria interface in CO oxidation, the water–gas shift, CO2 hydrogenation, and methane and alcohol reforming. Chem. Soc. Rev. 46, 1824–1841 (2017).

  17. 17.

    Mudiyanselage, K. et al. Importance of the metal–oxide interface in catalysis: in situ studies of the water–gas shift reaction by ambient-pressure X-ray photoelectron spectroscopy. Angew. Chem. Int. Ed. 52, 5101–5105 (2013).

  18. 18.

    Senanayake, S. D., Stacchiola, D. & Rodriguez, J. A. Unique properties of ceria nanoparticles supported on metals: novel inverse ceria/copper catalysts for CO oxidation and the water–gas shift reaction. Acc. Chem. Res. 46, 1702–1711 (2013).

  19. 19.

    Szabová, L., Camellone, M. F., Huang, M., Matolín, V. & Fabris, S. Thermodynamic, electronic and structural properties of Cu/CeO2 surfaces and interfaces from first-principles DFT + U calculations. J. Chem. Phys. 133, 234705 (2010).

  20. 20.

    Yang, Z., Xie, L., Ma, D. & Wang, G. Origin of the high activity of the ceria-supported copper catalyst for H2O dissociation. J. Phys. Chem. C 115, 6730–6740 (2011).

  21. 21.

    James, T. E., Hemmingson, S. L., Ito, T. & Campbell, C. T. Energetics of Cu adsorption and adhesion onto reduced CeO2(111) surfaces by calorimetry. J. Phys. Chem. C 119, 17209–17217 (2015).

  22. 22.

    James, T. E., Hemmingson, S. L. & Campbell, C. T. Energy of supported metal catalysts: from single atoms to large metal nanoparticles. ACS Catal. 5, 5673–5678 (2015).

  23. 23.

    Chutia, A. et al. The adsorption of Cu on the CeO2(110) surface. Phys. Chem. Chem. Phys. 19, 27191–27203 (2017).

  24. 24.

    Si, R. & Flytzani-Stephanopoulos, M. Shape and crystal-plane effects of nanoscale ceria on the activity of Au–CeO2 catalysts for the water–gas shift reaction. Angew. Chem. Int. Ed. 47, 2884–2887 (2008).

  25. 25.

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

  26. 26.

    Yamada, Y. et al. Nanocrystal bilayer for tandem catalysis. Nat. Chem. 3, 372–376 (2011).

  27. 27.

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

  28. 28.

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

  29. 29.

    Lin, Y. et al. Adhesion and atomic structures of gold on ceria nanostructures: the role of surface structure and oxidation state of ceria supports. Nano Lett. 15, 5375–5381 (2015).

  30. 30.

    Gänzler, A. M. et al. Tuning the Pt/CeO2 interface by in situ variation of the Pt particle size. ACS Catal. 8, 4800–4811 (2018).

  31. 31.

    Chen, A., Zhou, Y., Ta, N., Li, Y. & Shen, W. Redox properties and catalytic performance of ceria–zirconia nanorods. Catal. Sci. Technol. 5, 4184–4192 (2015).

  32. 32.

    Tang, X. et al. CuO/CeO2catalysts: redox features and catalytic behaviors. Appl. Catal. A 288, 116–125 (2005).

  33. 33.

    Wang, W. et al. Crystal plane effect of ceria on supported copper oxide cluster catalyst for CO oxidation: importance of metal–support Interaction. ACS Catal. 7, 1313–1329 (2017).

  34. 34.

    Wu, L. et al. Oxidation state and lattice expansion of CeO2–x nanoparticles as a function of particle size. Phys. Rev. B 69, 125415 (2004).

  35. 35.

    Keast, V. J., Scott, A. J., Brydson, R., Williams, D. B. & Bruley, J. Electron energy-loss near-edge structure—a tool for the investigation of electronic structure on the nanometre scale. J. Microsc. 203, 135–175 (2001).

  36. 36.

    Wagner, J. B. et al. In situ electron energy loss spectroscopy studies of gas-dependent metal–support interactions in Cu/ZnO catalysts. J. Phys. Chem. B 107, 7753–7758 (2003).

  37. 37.

    Wang, Y. & Wöll, C. IR spectroscopic investigations of chemical and photochemical reactions on metal oxides: bridging the materials gap. Chem. Soc. Rev. 46, 1875–1932 (2017).

  38. 38.

    Yang, C. et al. Chemical activity of oxygen vacancies on ceria: a combined experimental and theoretical study on CeO2(111). Phys. Chem. Chem. Phys. 16, 24165–24168 (2014).

  39. 39.

    Yang, C. et al. Surface faceting and reconstruction of ceria nanoparticles. Angew. Chem. Int. Ed. 56, 375–379 (2017).

  40. 40.

    Cox, D. F. & Schulz, K. H. Interaction of CO with Cu+ cations: CO adsorption on Cu2O(100). Surf. Sci. 249, 138–148 (1991).

  41. 41.

    Martı́nez-Arias, A., Fernández-Garcı́a, M., Soria, J. & Conesa, J. C. Spectroscopic study of a Cu/CeO2 catalyst subjected to redox treatments in carbon monoxide and oxygen. J. Catal. 182, 367–377 (1999).

  42. 42.

    Vollmer, S., Witte, G. & Wöll, C. Determination of site specific adsorption energies of CO on copper. Catal. Lett. 77, 97–101 (2001).

  43. 43.

    Chen, S. et al. Anchoring high-concentration oxygen vacancies at interfaces of CeO2–x/Cu toward enhanced activity for preferential CO oxidation. ACS Appl. Mater. Interfaces 7, 22999–23007 (2015).

  44. 44.

    Fabris, S., Vicario, G., Balducci, G., de Gironcoli, S. & Baroni, S. Electronic and atomistic structures of clean and reduced ceria surfaces. J. Phys. Chem. B 109, 22860–22867 (2005).

  45. 45.

    Lykhach, Y. et al. Counting electrons on supported nanoparticles. Nat. Mater. 15, 284–288 (2016).

  46. 46.

    Branda, M. M., Hernández, N. C., Sanz, J. F. & Illas, F. Density functional theory study of the interaction of Cu, Ag, and Au atoms with the regular CeO2(111) surface. J. Phys. Chem. C 114, 1934–1941 (2010).

  47. 47.

    Figueroba, A., Kovács, G., Bruix, A. & Neyman, K. M. Towards stable single-atom catalysts: strong binding of atomically dispersed transition metals on the surface of nanostructured ceria. Catal. Sci. Technol. 6, 6806–6813 (2016).

  48. 48.

    Li, L. et al. Water–gas shift reaction over CuO/CeO2 catalysts: effect of the thermal stability and oxygen vacancies of CeO2 supports previously prepared by different methods. Catal. Lett. 130, 532–540 (2009).

  49. 49.

    López. Cámara, A., Chansai, S., Hardacre, C. & Martínez-Arias, A. The water–gas shift reaction over CeO2/CuO: operando SSITKA–DRIFTS–mass spectrometry study of low temperature mechanism. Int. J. Hydrogen Energy 39, 4095–4101 (2014).

  50. 50.

    Caldas, P. C. P., Gallo, J. M. R., Lopez-Castillo, A., Zanchet, D. & Bueno, J. M. C. The structure of the Cu–CuO sites determines the catalytic activity of Cu nanoparticles. ACS Catal. 7, 2419–2424 (2017).

Download references


This work is supported by the National Natural Science Foundation of China (grant numbers 91645107, 21533009, 21621063 and 21761132031), the Deutsche Forschungsgemeinschaft (WA 2535/2-1), the ‘Science and Technology of Nanosystems’ Programme (grant no. 432202) of Germany and the EU-H2020 research and innovation programme (grant no. 654360 NFFA-Europe). X.Y. and C.Y. thank PhD fellowships sponsored by the China Scholarship Council.

Author information

Author notes

  1. These authors contributed equally: Aling Chen, Xiaojuan Yu.


  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China

    • Aling Chen
    • , Yan Zhou
    • , Shu Miao
    • , Yong Li
    • , Jing Ning
    • , Chuanchuan Jin
    •  & Wenjie Shen
  2. Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany

    • Xiaojuan Yu
    • , Chengwu Yang
    • , Alexei Nefedov
    • , Christof Wöll
    •  & Yuemin Wang
  3. Haldor Topsøe A/S, Kongens Lyngby, Denmark

    • Sebastian Kuld
    •  & Jens Sehested
  4. Department of Physics, Arizona State University, Tempe, AZ, USA

    • Jingyue Liu
  5. LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ, USA

    • Toshihiro Aoki
  6. Center for Instrumental Analysis, Beijing University of Chemical Technology, Beijing, China

    • Song Hong
  7. Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche CNR-IOM, Trieste, Italy

    • Matteo Farnesi Camellone
    •  & Stefano Fabris


  1. Search for Aling Chen in:

  2. Search for Xiaojuan Yu in:

  3. Search for Yan Zhou in:

  4. Search for Shu Miao in:

  5. Search for Yong Li in:

  6. Search for Sebastian Kuld in:

  7. Search for Jens Sehested in:

  8. Search for Jingyue Liu in:

  9. Search for Toshihiro Aoki in:

  10. Search for Song Hong in:

  11. Search for Matteo Farnesi Camellone in:

  12. Search for Stefano Fabris in:

  13. Search for Jing Ning in:

  14. Search for Chuanchuan Jin in:

  15. Search for Chengwu Yang in:

  16. Search for Alexei Nefedov in:

  17. Search for Christof Wöll in:

  18. Search for Yuemin Wang in:

  19. Search for Wenjie Shen in:


A.C., J.N., C.J. and Y.L. prepared the catalysts and conducted the reaction tests. X.Y., C.Y., A.N., C.W. and Y.W. performed the UHV infrared analysis. S.K. and J.S. performed chemical titrations and reaction tests. Y.Z., S.M., J.L., T.A. and S.H. conducted the STEM and EELS analyses. M.F.C. and S.F. performed the DFT calculations on the interfacial structure. S.F. and C.W. contributed to thorough discussions on this work. Y.Z., J.S., Y.W. and W.S. designed the experiments, analysed the data and wrote the paper.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Yan Zhou or Jens Sehested or Yuemin Wang or Wenjie Shen.

Supplementary information

  1. Supplementary information

    Supplementary Methods, Supplementary Discussion, Supplementary Figures 1–13, Supplementary Tables 1–6, Supplementary References

About this article

Publication history




Issue Date