Topics in Catalysis

, Volume 62, Issue 12–16, pp 849–858 | Cite as

Pt–Ga Model SCALMS on Modified HOPG: Growth and Adsorption Properties

  • Chantal Hohner
  • Miroslav KettnerEmail author
  • Corinna Stumm
  • Christian Schuschke
  • Matthias Schwarz
  • Jörg Libuda
Original Paper


Single atom catalysts hold a great potential in heterogeneous catalysis. In this model study, we report on the observation of Pt single atoms in low-melting-point Pt–Ga alloy prepared on modified highly oriented pyrolytic graphite (HOPG) under ultrahigh vacuum (UHV) conditions. In the first part, we examined the growth of Pt nanoparticles (NP) on HOPG modified by Ar+ bombardment. In the second part, we used physical vapor co-deposition of Pt and Ga to prepare model systems for supported catalytically active liquid metal solutions. We employed infrared reflection absorption spectroscopy with CO as a probe molecule and atomic force microscopy to study the growth and adsorption properties of Pt–Ga aggregates in comparison to Pt NPs. The presence of CO during Pt deposition leads to formation of ordered Pt particles mainly exposing terrace sites. On Pt–Ga nanoalloys, CO induces Pt segregation to the surface. In contrast, Ga deposition onto Pt in UHV or evaporation of small amounts of Pt onto Ga results in the formation of isolated Pt atoms on the surface of the alloy. Comparing alloys with different Pt concentrations, we show that the coordination environment around Pt influences the binding energy of the adsorbed CO.


Platinum Gallium Highly oriented pyrolytic graphite (HOPG) Infrared reflection absorption spectroscopy (IRAS) Atomic force microscopy (AFM) Supported catalytically active liquid metal solutions (SCALMS) 



This project was financially supported by the Deutsche Forschungsgemeinschaft (DFG). In particular we acknowledge support by the DFG from the Excellence Cluster ‘Engineering of Advanced Materials’ (Bridge Funding).


  1. 1.
    Liu J (2017) Catalysis by supported single metal atoms. ACS Catal 7:34–59. CrossRefGoogle Scholar
  2. 2.
    Liang S, Hao C, Shi Y (2015) The power of single-atom catalysis. ChemCatChem 7:2559–2567. CrossRefGoogle Scholar
  3. 3.
    Wang A, Li J, Zhang T (2018) Heterogeneous single-atom catalysis. Nat Rev Chem 2:65–81. CrossRefGoogle Scholar
  4. 4.
    Lykhach Y, Bruix A, Fabris S et al (2017) Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles. Catal Sci Technol 7:4315–4345. CrossRefGoogle Scholar
  5. 5.
    Li H, Zhang H, Yan X et al (2018) Carbon-supported metal single atom catalysts. New Carbon Mater 33:1–11. CrossRefGoogle Scholar
  6. 6.
    Kyriakou G, Boucher MB, Jewell AD et al (2012) Isolated metal atom geometries as a strategy for selective heterogeneous hydrogenations. Science 335:1209–1212. CrossRefPubMedGoogle Scholar
  7. 7.
    Im J, Choi M (2016) Physicochemical stabilization of Pt against sintering for a dehydrogenation catalyst with high activity, selectivity, and durability. ACS Catal 6:2819–2826. CrossRefGoogle Scholar
  8. 8.
    Redekop EA, Galvita VV, Poelman H et al (2014) Delivering a modifying element to metal nanoparticles via support: Pt-Ga alloying during the reduction of Pt/Mg(Al, Ga)Ox catalysts and its effects on propane dehydrogenation. ACS Catal 4:1812–1824. CrossRefGoogle Scholar
  9. 9.
    Sattler JJHB, Gonzalez-Jimenez ID, Luo L et al (2014) Platinum-promoted Ga/Al2O3 as highly active, selective, and stable catalyst for the dehydrogenation of propane. Angew Chemie Int Ed 53:9251–9256. CrossRefGoogle Scholar
  10. 10.
    Föttinger K, Rupprechter G (2014) In situ spectroscopy of complex surface reactions on supported Pd–Zn, Pd–Ga, and Pd(Pt)–Cu nanoparticles. Acc Chem Res 47:3071–3079. CrossRefPubMedGoogle Scholar
  11. 11.
    Haghofer A, Föttinger K, Girgsdies F et al (2012) In situ study of the formation and stability of supported Pd2Ga methanol steam reforming catalysts. J Catal 286:13–21. CrossRefGoogle Scholar
  12. 12.
    Taccardi N, Grabau M, Debuschewitz J et al (2017) Gallium-rich Pd–Ga phases as supported liquid metal catalysts. Nat Chem 9:862–867. CrossRefPubMedGoogle Scholar
  13. 13.
    Kettner M, Maisel S, Stumm C et al (2019) Pd-Ga model SCALMS: characterization and stability of Pd single atom sites. J Catal 369:33–46. CrossRefGoogle Scholar
  14. 14.
    Grabau M, Erhard J, Taccardi N et al (2017) Spectroscopic observation and molecular dynamics simulation of Ga surface segregation in liquid Pd-Ga alloys. Chem-A 23:17701–17706. CrossRefGoogle Scholar
  15. 15.
    Upham DC, Agarwal V, Khechfe A et al (2017) Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon. Science 921:917–921. CrossRefGoogle Scholar
  16. 16.
    Rodríguez-Reinoso F (1998) The role of carbon materials in heterogeneous catalysis. Carbon NY 36:159–175. CrossRefGoogle Scholar
  17. 17.
    Mao X, Rutledge GC, Hatton TA (2014) Nanocarbon-based electrochemical systems for sensing, electrocatalysis, and energy storage. Nano Today 9:405–432. CrossRefGoogle Scholar
  18. 18.
    Lee J, Kim J, Hyeon T (2006) Recent progress in the synthesis of porous carbon materials. Adv Mater 18:2073–2094. CrossRefGoogle Scholar
  19. 19.
    Favaro M, Agnoli S, Perini L et al (2013) Palladium nanoparticles supported on nitrogen-doped HOPG: a surface science and electrochemical study. Phys Chem Chem Phys 15:2923. CrossRefPubMedGoogle Scholar
  20. 20.
    Yang DQ, Sacher E (2002) Ar+-induced surface defects on HOPG and their effect on the nucleation, coalescence and growth of evaporated copper. Surf Sci 516:43–55. CrossRefGoogle Scholar
  21. 21.
    Faisal F, Toghan A, Khalakhan I et al (2015) Characterization of thin CeO2 films electrochemically deposited on HOPG. Appl Surf Sci 350:142–148. CrossRefGoogle Scholar
  22. 22.
    Bolina AS, Wolff AJ, Brown WA (2005) Reflection absorption infrared spectroscopy and temperature-programmed desorption studies of the adsorption and desorption of amorphous and crystalline water on a graphite surface. J Phys Chem B 109:16836–16845. CrossRefPubMedGoogle Scholar
  23. 23.
    Bolina AS, Wolff AJ, Brown WA (2005) Reflection absorption infrared spectroscopy and temperature programmed desorption investigations of the interaction of methanol with a graphite surface. J Chem Phys 122:44713. CrossRefPubMedGoogle Scholar
  24. 24.
    Heidberg J, Warskulat M, Folman M (1990) Fourier-transform-infrared spectroscopy of carbon monoxide physisorbed on highly oriented graphite. J Electron Spectros Relat Phenom 54–55:961–970. CrossRefGoogle Scholar
  25. 25.
    Boyd DA, Hess FM, Hess GB (2002) Infrared absorption study of physisorbed carbon monoxide on graphite. Surf Sci 519:125–138. CrossRefGoogle Scholar
  26. 26.
    Nalezinski R, Bradshaw AM, Knorr K (1995) Orientational phase transitions in polar physisorbed molecules: an IRAS study of dichlorodifluoromethane on graphite. Surf Sci 331–333:255–260. CrossRefGoogle Scholar
  27. 27.
    Nalezinski R, Bradshaw AM, Knorr K (1997) A vibrational spectroscopy study of the orientational ordering in CH3Cl monolayers physisorbed on graphite. Surf Sci 393:222–230. CrossRefGoogle Scholar
  28. 28.
    Kettner M, Stumm C, Schwarz M et al (2019) Pd model catalysts on clean and modified HOPG: growth, adsorption properties, and stability. Surf Sci 679:64–73. CrossRefGoogle Scholar
  29. 29.
    Kovnir K, Armbrüster M, Teschner D et al (2007) A new approach to well-defined, stable and site-isolated catalysts. Sci Technol Adv Mater 8:420–427. CrossRefGoogle Scholar
  30. 30.
    Prinz J, Gaspari R, Stöckl QS et al (2014) Ensemble effect evidenced by CO adsorption on the 3-fold PdGa surfaces. J Phys Chem C 118:12260–12265. CrossRefGoogle Scholar
  31. 31.
    Nečas D, Klapetek P (2012) Gwyddion: an open-source software for SPM data analysis. Cent Eur J Phys 10:181–188. CrossRefGoogle Scholar
  32. 32.
    Greenler RG, Brandt RK (1995) The origins of multiple bands in the infrared spectra of carbon monoxide adsorbed on metal surfaces. Colloids Surf A 105:19–26. CrossRefGoogle Scholar
  33. 33.
    Haneda M, Watanabe T, Kamiuchi N, Ozawa M (2013) Effect of platinum dispersion on the catalytic activity of Pt/Al2O3for the oxidation of carbon monoxide and propene. Appl Catal B 142–143:8–14. CrossRefGoogle Scholar
  34. 34.
    Lundwall MJ, McClure SM, Goodman DW (2010) Probing terrace and step sites on Pt nanoparticles using CO and ethylene. J Phys Chem C 114:7904–7912. CrossRefGoogle Scholar
  35. 35.
    Primet M (1984) Electronic transfer and ligand effects in the infrared spectra of adsorbed carbon monoxide. J Catal 88:273–282. CrossRefGoogle Scholar
  36. 36.
    Steininger H, Lehwald S, Ibach H (1982) On the adsorption of CO on Pt (111). Surf Sci 123:264–282. CrossRefGoogle Scholar
  37. 37.
    Kung KY, Chen P, Wei F et al (2000) Sum-frequency generation spectroscopic study of CO adsorption and dissociation on Pt(111) at high pressure and temperature. Surf Sci 463:627–633. CrossRefGoogle Scholar
  38. 38.
    Klünker C, Balden M, Lehwald S, Daum W (1996) CO stretching vibrations on Pt(111) and Pt(110) studied by sum-frequency generation. Surf Sci 360:104–111. CrossRefGoogle Scholar
  39. 39.
    Tüshaus M, Schweizer E, Hollins P, Bradshaw AM (1987) Yet another vibrational study of the adsorption system Pt{111}-CO. J Electron Spectros Relat Phenom 44:305–316. CrossRefGoogle Scholar
  40. 40.
    Hayden BE, Bradshaw AM (1983) The adsorption of CO on Pt(111) studied by infrared-reflection-adsorption spectroscopy. J Electron Spectros Relat Phenom 30:51. CrossRefGoogle Scholar
  41. 41.
    Yang DQ, Zhang GX, Sacher E et al (2006) Evidence of the interaction of evaporated Pt nanoparticles with variously treated surfaces of highly oriented pyrolytic graphite. J Phys Chem B 110:8348–8356. CrossRefPubMedGoogle Scholar
  42. 42.
    Primet M, Basset JM, Mathieu MV, Prettre M (1973) Infrared study of CO adsorbed on Pt Al2O3. A method for determining metal-adsorbate interactions. J Catal 29:213–223. CrossRefGoogle Scholar
  43. 43.
    Jin T, Zhou Y, Mains GJ, White JM (1987) Infrared and x-ray photoelectron spectroscopy study of carbon monoxide and carbon dioxide on platinum/ceria. J Phys Chem 91:5931–5937. CrossRefGoogle Scholar
  44. 44.
    Fox SG, Browne VM, Hollins P (1990) Correlated infrared studies of platinum single crystals and supported catalysts. J Electron Spectros Relat Phenom 54–55:749–758. CrossRefGoogle Scholar
  45. 45.
    Sobota M, Happel M, Amende M et al (2011) Ligand effects in SCILL model systems: site-specific interactions with Pt and Pd nanoparticles. Adv Mater 23:2617–2621. CrossRefPubMedGoogle Scholar
  46. 46.
    Brandt RK, Hughes MR, Bourget LP et al (1993) The interpretation of CO adsorbed on Pt/SiO2of two different particle-size distributions. Surf Sci 286:15–25. CrossRefGoogle Scholar
  47. 47.
    Podkolzin SG, Shen J, De Pablo JJ, Dumesic JA (2000) Equilibrated adsorption of CO on silica-supported Pt catalysts. J Phys Chem B 104:4169–4180. CrossRefGoogle Scholar
  48. 48.
    Hollins P (1992) The influence of surface defects on the infrared spectra of adsorbed species. Surf Sci Rep 16:51–94. CrossRefGoogle Scholar
  49. 49.
    Barth R, Pitchai R (1989) Thermal desorption-infrared study of carbon monoxide adsorption by alumina-supported platinum. J Catal 70:61–70. CrossRefGoogle Scholar
  50. 50.
    Bourane A, Dulaurent O, Bianchi D (2000) Heats of adsorption of linear and multibound adsorbed CO species on a Pt/Al2O3catalyst using in situ infrared spectroscopy under adsorption equilibrium. J Catal 196:115–125. CrossRefGoogle Scholar
  51. 51.
    Ertl G, Neumann M, Streit KM (1977) Chemisorption of CO on the Pt(111) surface. Surf Sci 64:393–410. CrossRefGoogle Scholar
  52. 52.
    Bauer T, Maisel S, Blaumeiser D, et al (2019) Operando DRIFTS and DFT study of propane dehydrogenation over solid- and liquid-supported GaxPty catalysts. ACS Catal 9:2842–2853. CrossRefGoogle Scholar
  53. 53.
    Therrien AJ, Hensley AJR, Marcinkowski MD et al (2018) An atomic-scale view of single-site Pt catalysis for low-temperature CO oxidation. Nat Catal 1:192–198. CrossRefGoogle Scholar
  54. 54.
    Qiao B, Wang A, Yang X et al (2011) Single-atom catalysis of CO oxidation using Pt1/FeOx. Nat Chem 3:634–641. CrossRefPubMedGoogle Scholar
  55. 55.
    Moses-Debusk M, Yoon M, Allard LF et al (2013) CO oxidation on supported single Pt atoms: experimental and ab initio density functional studies of CO interaction with Pt atom on θ-Al2O3(010) surface. J Am Chem Soc 135:12634–12645. CrossRefPubMedGoogle Scholar
  56. 56.
    Brummel O, Waidhas F, Faisal F et al (2016) Stabilization of small platinum Nanoparticles on Pt-CeO2 thin film electrocatalysts during methanol oxidation. J Phys Chem C 120:19723–19736. CrossRefGoogle Scholar
  57. 57.
    Redhead PA (1962) Thermal desorption of gases. Vacuum 12:203–211. CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergErlangenGermany
  2. 2.Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface Controlled ProcessesFriedrich-Alexander-Universität Erlangen-NürnbergErlangenGermany

Personalised recommendations