Freestanding palladium nanosheets with plasmonic and catalytic properties

Article metrics


Ultrathin metal films can exhibit quantum size and surface effects that give rise to unique physical and chemical properties1,2,3,4,5,6,7. Metal films containing just a few layers of atoms can be fabricated on substrates using deposition techniques7, but the production of freestanding ultrathin structures remains a significant challenge. Here we report the facile synthesis of freestanding hexagonal palladium nanosheets that are less than 10 atomic layers thick, using carbon monoxide as a surface confining agent. The as-prepared nanosheets are blue in colour and exhibit a well-defined but tunable surface plasmon resonance peak in the near-infrared region. The combination of photothermal stability and biocompatibility makes palladium nanosheets promising candidates for photothermal therapy. The nanosheets also exhibit electrocatalytic activity for the oxidation of formic acid that is 2.5 times greater than that of commercial palladium black catalyst.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Characterization of ultrathin palladium nanosheets synthesized in the presence of PVP and CTAB in DMF.
Figure 2: TEM images of the palladium nanosheets produced under different reaction conditions.
Figure 3: Optical absorption and photothermal properties of palladium nanosheets.
Figure 4: Comparison of electrocatalytic properties of palladium nanosheets and palladium black.


  1. 1

    Smith, A. R., Chao, K. J., Niu, Q. & Shih, C. K. Formation of atomically flat silver films on GaAs with a ‘silver mean’ quasi periodicity. Science 273, 226–228 (1996).

  2. 2

    Zhang, Z. Y., Niu, Q. & Shih, C. K. ‘Electronic growth’ of metallic overlayers on semiconductor substrates. Phys. Rev. Lett. 80, 5381–5384 (1998).

  3. 3

    Paggel, J. J., Miller, T. & Chiang, T. C. Quantum-well states as Fabry–Perot modes in a thin-film electron interferometer. Science 283, 1709–1711 (1999).

  4. 4

    Guo, Y. et al. Superconductivity modulated by quantum size effects. Science 306, 1915–1917 (2004).

  5. 5

    Qin, S. Y., Kim, J., Niu, Q. & Shih, C. K. Superconductivity at the two-dimensional limit. Science 324, 1314–1317 (2009).

  6. 6

    Ozer, M. M. et al. Tuning the quantum stability and superconductivity of ultrathin metal alloys. Science 316, 1594–1597 (2007).

  7. 7

    Campbell, C. T. Ultrathin metal films and particles on oxide surfaces: structural, electronic and chemisorptive properties. Surf. Sci. Rep. 27, 1–111 (1997).

  8. 8

    Gordon, R., Sinton, D., Kavanagh, K. L. & Brolo, A. G. A new generation of sensors based on extraordinary optical transmission. Acc. Chem. Res. 41, 1049–1057 (2008).

  9. 9

    Langhammer, C., Yuan, Z., Zoric, I. & Kasemo, B. Plasmonic properties of supported Pt and Pd nanostructures. Nano Lett. 6, 833–838 (2006).

  10. 10

    Lal, S., Clare, S. E. & Halas, N. J. Nanoshell-enabled photothermal cancer therapy: impending clinical impact. Acc. Chem. Res. 41, 1842–1851 (2008).

  11. 11

    Jain, P. K., Huang, X. H., El-Sayed, I. H. & El-Sayed, M. A. Noble metals on the nanoscale: optical and photothermal properties and some applications in imaging, sensing, biology, and medicine. Acc. Chem. Res. 41, 1578–1586 (2008).

  12. 12

    Skrabalak, S. E. et al. Gold nanocages: synthesis, properties, and applications. Acc. Chem. Res. 41, 1587–1595 (2008).

  13. 13

    Calander, N. Molecular detection and analysis by using surface plasmon resonances. Curr. Anal. Chem. 2, 203–211 (2006).

  14. 14

    Schaadt, D. M., Feng, B. & Yu, E. T. Enhanced semiconductor optical absorption via surface plasmon excitation in metal nanoparticles. Appl. Phys. Lett. 86, 063106 (2005).

  15. 15

    Krenn, J. R. Nanoparticle waveguides—watching energy transfer. Nature Mater. 2, 210–211 (2003).

  16. 16

    Larsson, E. M., Langhammer, C., Zoric, I. & Kasemo, B. Nanoplasmonic probes of catalytic reactions. Science 326, 1091–1094 (2009).

  17. 17

    Jin, R. C. et al. Controlling anisotropic nanoparticle growth through plasmon excitation. Nature 425, 487–490 (2003).

  18. 18

    Jin, R. C. et al. Photoinduced conversion of silver nanospheres to nanoprisms. Science 294, 1901–1903 (2001).

  19. 19

    Murphy, C. J. et al. Anisotropic metal nanoparticles: synthesis, assembly, and optical applications. J. Phys. Chem. B 109, 13857–13870 (2005).

  20. 20

    Jain, P. K., Huang, X. H., El-Sayed, I. H. & El-Sayad, M. A. Review of some interesting surface plasmon resonance-enhanced properties of noble metal nanoparticles and their applications to biosystems. Plasmonics 2, 107–118 (2007).

  21. 21

    Link, S. et al. Laser photothermal melting and fragmentation of gold nanorods: energy and laser pulse-width dependence. J. Phys. Chem. A 103, 1165–1170 (1999).

  22. 22

    Yavuz, M. S. et al. Gold nanocages covered by smart polymers for controlled release with near-infrared light. Nature Mater. 8, 935–939 (2009).

  23. 23

    Xia, Y., Xiong, Y. J., Lim, B. & Skrabalak, S. E. Shape-controlled synthesis of metal nanocrystals: simple chemistry meets complex physics? Angew. Chem. Int. Ed. 48, 60–103 (2009).

  24. 24

    Xiong, Y. J. & Xia, Y. N. Shape-controlled synthesis of metal nanostructures: the case of palladium. Adv. Mater. 19, 3385–3391 (2007).

  25. 25

    Germain, V. et al. Stacking faults in formation of silver nanodisks. J. Phys. Chem. B 107, 8717–8720 (2003).

  26. 26

    Hara, M., Linke, U. & Wandlowski, T. Preparation and electrochemical characterization of palladium single crystal electrodes in 0.1 M H2SO4 and HClO4 part I. Low-index phases. Electrochim. Acta 52, 5733–5748 (2007).

  27. 27

    Schlotterbeck, U. et al. Shape-selective synthesis of palladium nanoparticles stabilized by highly branched amphiphilic polymers. Adv. Funct. Mater. 14, 999–1004 (2004).

  28. 28

    Siril, P. F. et al. Synthesis of ultrathin hexagonal palladium nanosheets. Chem. Mater. 21, 5170–5174 (2009).

  29. 29

    Xiong, Y. J. et al. Synthesis and mechanistic study of palladium nanobars and nanorods. J. Am. Chem. Soc. 129, 3665–3675 (2007).

  30. 30

    Orendorff, C. J. & Murphy, C. J. Quantitation of metal content in the silver-assisted growth of gold nanorods. J. Phys. Chem. B 110, 3990–3994 (2006).

  31. 31

    Huang, X. H., El-Sayed, I. H., Qian, W. & El-Sayed, M. A. Cancer cell imaging and photothermal therapy in the near-infrared region by using gold nanorods. J. Am. Chem. Soc. 128, 2115–2120 (2006).

  32. 32

    Hirsch, L. R. et al. Nanoshell-mediated near-infrared thermal therapy of tumors under magnetic resonance guidance. Proc. Natl Acad. Sci. USA 100, 13549–13554 (2003).

  33. 33

    Chen, J. Y. et al. Immuno gold nanocages with tailored optical properties for targeted photothermal destruction of cancer cells. Nano Lett. 7, 1318–1322 (2007).

Download references


The authors acknowledge helpful discussions with L.S. Zheng, Z.Q. Tian, G.D. Stucky, Z.X. Xie and B.W. Mao. The authors also thank S.W. Boettcher and Z.P. Zheng for suggestions and editing of the English. This work was supported by the NSF of China (20925103, 20871100, 20721001 and 20703032), MOST of China (2009CB930703, 2011CB932403), the Fok Ying Tung Education Foundation (121011), NSF of Fujian for a Distinguished Young Investigator Grant (2009J06005) and the Key Scientific Project of Fujian Province (2009HZ0002-1).

Author information

X.Q.H. performed the experiments, collected and analysed the data, and wrote the paper. S.H.T. carried out the apoptosis assay and in vitro photothermal therapy tests. X.L.M. was responsible for AFM analysis. Y.D. and G.X.C. helped with synthesis of the materials. Z.Y.Z. helped with the electrochemical and FTIR measurements. F.X.R. and Z.L.Y. carried out the calculations of extinction spectra. N.F.Z. conceived the experiments, planned the synthesis, analysed the results and wrote the paper.

Correspondence to Nanfeng Zheng.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 3840 kb)

Rights and permissions

Reprints and Permissions

About this article

Further reading