English

Atomic Structure and Adsorption Property of the Singly Dispersed Au/Cu(111) Surface Alloy

• Wang Wenyuan ,
• Zhang Jiefu ,
• Li Zhe ,
• Shao Xiang ^,

• Department of Chemical Physics, CAS Key Laboratory of Urban Pollutant Conversion, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, P. R. China

Corresponding author: Xiang Shao, Email: shaox@ustc.edu.cn; Tel.: +86-551-63600765

• Received Date: 19 November 2019
  Accepted Date: 27 December 2019
  Revised Date: 25 December 2019
  Available Online: 15 August 2020
• Fund Project:

  The project was supported by the National Natural Science Foundation of China (21872130, 91545128) and the National Key Research and Development Program of China (2017YFA0205003)

Abstract: Atomic-scale characterization of the atomic structure as well as molecular adsorption on an alloy surface plays a vital role in elucidating the catalytic mechanism of effective catalysts. Au-Cu alloy nanoparticles have important applications in catalyzing CO oxidation and CO₂ reduction. However, the atomic-scale properties of Au-Cu alloy surfaces are rarely investigated. In particular, the physical and chemical properties of singly-dispersed doping atoms, either Au in Cu or vice versa, as well as their influence on the overall surface properties, have not been studied in detail. In response, we first prepared low-coverage bimetallic Au/Cu(111) and Cu/Au(111) films, which were then annealed at high temperature to realize single atomically-dispersed Au/Cu(111) and Cu/Au(111) surface alloys (SA). We characterized the surface structures and adsorption properties by low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/STS). For the SA-Au/Cu(111) system, we found that Au atoms can be incorporated in both the skin and subsurface layer of the Cu(111) substrate. These species can be readily distinguished from the topography contrast in STM. Moreover, STS measurements showed clear differences between the electronic states of doped Au atoms and the Cu host. In particular, we found that Au in the skin layer was strengthened while the subsurface Au showed weakened filled states at approximately −0.5 eV compared with the Cu(111) surface, which corresponds to the characteristic Shockley state of an Au surface. These altered electronic properties at the sites of doped atoms are also reflected by changes in the interactions with probe molecules. Adsorption experiments showed that Au atoms in the top surface prevented the binding of CO molecules, causing various adsorption vacancies in the CO adlayer. In contrast, the subsurface Au atoms had little influence on surface binding with CO molecules. For the SA-Cu/Au(111) system, we found that Cu atoms tend to aggregate into small clusters in the subsurface region of the Au(111) substrate. Only few Cu atoms can be stabilized at the elbow positions of the reconstructed top surface of Au(111). Adsorption experiments showed that only Cu atoms in the skin layer can adsorb CO molecules at liquid nitrogen temperature, while the subsurface Cu atoms cannot. On the other hand, the Au atoms around the doped Cu atoms do not seem to be influenced at all, possibly because of the weak effect of Cu. These experimental results provide details on the atomistic aspects of Au-Cu alloy surfaces, which can improve our understanding of the catalytic mechanism of Au-Cu alloy catalysts.

Key words:
• Au/Cu(111)
•  /  Single atom
•  /  Surface alloy
•  /  CO adsorption
•  /  Electronic property
•  /  Scanning tunneling microscopy

• 1. [1]

     Kim, D.; Resasco, J.; Yu, Y.; Asiri, A. M.; Yang, P. D. Nat. Commun. 2014, 5, 4948. doi: 10.1038/ncomms5948

  2. [2]

     Liu, X. Y.; Wang, A. Q.; Zhang, T.; Su, D. S.; Mou, C. Y. Catal. Today 2011, 160, 103. doi: 10.1016/j.cattod.2010.05.019

  3. [3]

     Haruta, M. Catal. Today 1997, 36, 153. doi: 10.1016/S0920-5861(96)00208-8

  4. [4]

     Thomas, J. M.; Saghi, Z.; Gai, P. L. Top. Catal. 2011, 54, 588. doi: 10.1007/s11244-011-9677-y

  5. [5]

     Qiao, B.; Wang, A.; Yang, X.; Allard, L. F.; Jiang, Z.; Cui, Y.; Liu, J.; Li, J.; Zhang, T. Nat. Chem. 2011, 3, 634. doi: 10.1038/nchem.1095

  6. [6]

     Ranocchiari, M.; Lothschutz, C.; Grolimund, D.; van Bokhoven, J. A. Proc. Roy. Soc. A 2012, 468, 1985. doi: 10.1098/rspa.2012.0078

  7. [7]

     Flytzani-Stephanopoulos, M.; Gates, B. C. Annu. Rev. Chem. Biomol. 2012, 3, 545. doi: 10.1146/annurev-chembioeng-062011-080939

  8. [8]

     Chen, J. G.; Menning, C. A.; Zellner, M. B. Surf. Sci. Rep. 2008, 63, 201. doi: 10.1016/j.surfrep.2008.02.001

  9. [9]

     Greeley, J.; Mavrikakis, M. Nat. Mater. 2004, 3, 810. doi: 10.1038/nmat1223

  10. [10]

      Rodriguez, J. Surf. Sci. Rep. 1996, 24, 223. doi: 10.1016/0167-5729(96)00004-0

  11. [11]

      Alexeev, O. S.; Gates, B. C. Ind. Eng. Chem. Res. 2003, 42, 1571. doi: 10.1021/ie020351h

  12. [12]

      Ponec, V. Appl. Catal. A 2001, 222, 31. doi: 10.1016/S0926-860X(01)00828-6

  13. [13]

      黄丽丽, 邵翔.物理化学学报, 2018, 34, 1390. doi: 10.3866/PKU.WHXB201804191Huang, L.; Shao, X. Acta Phys. -Chim. Sin. 2018, 34, 1390. doi: 10.3866/PKU.WHXB201804191

  14. [14]

      Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S. J. Catal. 1989, 115, 301. doi: 10.1016/0021-9517(89)90034-1

  15. [15]

      Haruta, M.; Tsubota, S.; Kobayashi, T.; Kageyama, H.; Genet, M. J.; Delmon, B. J. Catal. 1993, 144, 175. doi: 10.1006/jcat.1993.1322

  16. [16]

      Haruta, M. Catal. Today 1997, 36, 153. doi: 10.1016/S0920-5861(96)00208-8

  17. [17]

      Grisel, R. J. H.; Kooyman, P. J.; Nieuwenhuys, B. E. J. Catal. 2000, 191, 430. doi: 10.1006/jcat.1999.2787

  18. [18]

      Linke, R.; Schneider, U.; Busse, H.; Becker, C.; Schröder, U.; Castro, G. R.; Wandelt, K. Surf. Sci. 1994, 307, 407. doi: 10.1016/0039-6028(94)90427-8

  19. [19]

      Qi, Y.; Bian, T.; Choi, S. I.; Jiang, Y.; Jin, C.; Fu, M.; Zhang, H.; Yang, D. Chem. Commun. 2014, 50, 560. doi: 10.1039/c3cc48061e

  20. [20]

      Liu, X.; Wang, A.; Wang, X.; Mou, C. Y.; Zhang, T. Chem. Commun. 2008, 3187. doi: 10.1039/b804362k

  21. [21]

      Liu, X.; Wang, A.; Li, L.; Zhang, T.; Mou, C. Y.; Lee, J. F. J. Catal. 2011, 278, 288. doi: 10.1016/j.jcat.2010.12.016

  22. [22]

      Chimentão, R. J.; Medina, F.; Fierro, J. L. G.; Llorca, J.; Sueiras, J. E.; Cesteros, Y.; Salagre, P. J. Mater. Chem. A-Chem. 2007, 274, 159. doi: 10.1016/j.molcata.2007.05.008

  23. [23]

      Della Pina, C.; Falletta, E.; Rossi, M. J. Catal. 2008, 260, 384. doi: 10.1016/j.jcat.2008.10.003

  24. [24]

      Kyriakou, G.; Boucher, M. B.; Jewell, A. D.; Lewis, E. A.; Lawton, T. J.; Baber, A. E.; Tierney, H. L.; Stephanopoulos, M. F.; Sykes, E. C. H. Science 2012, 335, 1209. doi: 10.1126/science.1215864

  25. [25]

      Marcinkowski, M.; Jewell, A. D.; Stamatakis, M.; Boucher, M. B.; Lewis, E. A.; Murphy, C. J.; Kyriakou, G.; Sykes, E. C. H. Nat. Mater. 2013, 12, 523. doi: 10.1038/nmat3620

  26. [26]

      Baber, A. E.; Tierney, H. L.; Sykes, E. C. H. ACS Nano 2010, 4, 1637. doi: 10.1021/nn901390y

  27. [27]

      Han, P.; Axnanda, S.; Lyubinetsky, I.; Goodman, D. W. J. Am. Chem. Soc. 2007, 129, 14355. doi: 10.1021/ja074891n

  28. [28]

      Shi, H. X.; Wang, W. Y.; Li, Z.; Wang, L.; Shao, X. Chin. J. Chem. Phys. 2017, 30, 443. doi: 10.1063/1674-0068/30/cjcp1704078

  29. [29]

      Umezawa, K.; Nakanishi, S. Phys. Rev. B 2000, 63, 035402. doi: 10.1103/PhysRevB.63.035402

  30. [30]

      Wang, L.; Li, P.; Shi, H. X.; Li, Z. Y.; Wu, K.; Shao, X. J. Phys. Chem. C 2017, 121, 7977. doi: 10.1021/acs.jpcc.7b00938

  31. [31]

      Zhao, X. Y.; Liu, P.; Hrbek, J.; Rodriguez, J. A.; Pérez, M. Surf. Sci. 2005, 592, 25. doi: 10.1016/j.susc.2005.06.035

  32. [32]

      Hwang, R. Q.; Schröder, J.; Günther, C.; Behm, R. J. Phys. Rev. Lett. 1991, 67, 3279. doi: 10.1103/PhysRevLett.67.3279

  33. [33]

      Brune, H.; Röder, H.; Bromann, K.; Kern, K. Thin Solid Films 1995, 264, 230. doi: 10.1016/0040-6090(94)05821-0

  34. [34]

      Wang, W.; Shi, H.; Wang, L.; Li, Z.; Shi, H.; Wu, K.; Shao, X. J. Phys. Chem. C 2018, 122, 19551. doi: 10.1021/acs.jpcc.8b04783

  35. [35]

      Meunier, I.; Tréglia, G.; Gay, J. M.; Aufray, B. Phys. Rev. B 1999, 59, 10910. doi: 10.1103/PhysRevB.59.10910

  36. [36]

      Castro, G. R.; Doyen, G. Surf. Sci. 1994, 307, 384. doi: 10.1016/0039-6028(94)90423-5

  37. [37]

      Castro, G. R.; Schneider, U.; Busse, H.; Janssens, T.; Wandelt, K. Surf. Sci. 1992, 269, 321. doi: 10.1016/0039-6028(92)91268-G

  38. [38]

      Besenbacher, F.; Chorkendorff, I.; Clausen, B. S.; Hammer, B.; Molenbroek, A. M.; Nørskov, J. K.; Stensgaard, I. Science 1998, 279, 1913. doi: 10.1126/science.279.5358.1913

  39. [39]

      Kim, M. J.; Na, H. J.; Lee, K. C.; Yoob, E. A.; Lee, M. Y. J. Mater. Chem. 2003, 13, 1789. doi: 10.1039/b304006m

  40. [40]

      Liu, M.; Zhou, W.; Wang, T.; Wang, D.; Liu, L.; Ye, J. Chem. Commun. 2016, 52, 4694. doi: 10.1039/c6cc00717a

  41. [41]

      Kuhn, M.; Sham, T. K. Phys. Rev. B 1994, 49, 1647. doi: 10.1103/PhysRevB.49.1647

  42. [42]

      Hammer, B. J. K. N.; Nørskov, J. K. Surf. Sci. 1995, 343, 211. doi: 10.1016/0039-6028(96)80007-0

  43. [43]

      Libisch, F.; Geringer, V.; Subramaniam, D.; Burgdörfer, J.; Morgenstern, M. Phys. Rev. B 2014, 90, 035442. doi: 10.1103/PhysRevB.90.035442

  44. [44]

      Chen, W.; Madhavan, V.; Jamneala, T.; Crommie, M. F. Phys. Rev. Lett. 1998, 80, 1469. doi: 10.1103/PhysRevLett.80.1469

  45. [45]

      Bartels, L.; Meyer, G.; Rieder, K. H. Surf. Sci. 1999, 432, 621. doi: 10.1016/S0039-6028(99)00640-8

  46. [46]

      Heinrich, A. J.; Lutz, C. P.; Gupta, J. A.; Eigler, D. M. Science 2002, 298, 1381. doi: 10.1126/science.1076768

  47. [47]

      Neef, M.; Doll, K. Surf. Sci. 2006, 600, 1085. doi: 10.1016/j.susc.2005.12.036

  48. [48]

      Li, W.; Kong, L.; Feng, B.; Fu, H.; Li, H.; Zeng, X. C.; Wu, K.; Chen, L. Nat. Commun. 2018, 9, 198. doi: 10.1038/s41467-017-02634-6

  49. [49]

      Hammer, B.; Morikawa, Y.; Nørskov, J. K. Phys. Rev. Lett. 1996, 76, 2141. doi: 10.1103/PhysRevLett.76.2141

  50. [50]

      Mavrikakis, M.; Hammer, B.; Nørskov, J. K. Phys. Rev. Lett. 1998, 81, 2819. doi: 10.1103/PhysRevLett.81.2819

  51. [51]

      Rodriguez, J. A.; Goodman, D. W. Science 1992, 257, 897. doi: 10.1126/science.257.5072.897

  52. [52]

      Campbell, R. A.; Rodriguez, J. A.; Goodman, D. W. Surf. Sci. 1991, 256, 272. doi: 10.1016/0039-6028(91)90870-X

  53. [53]

      Rodriguez, J. A.; Goodman, D. W. J. Phys. Chem. 1991, 95, 4196. doi: 10.1021/j100164a008

  54. [54]

      Chen, M. S.; Goodman, D. W. Science 2004, 306, 252. doi: 10.1126/science.1102420

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