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Models for Heterogeneous Catalysts: complex materials at the atomic level.

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Models for Heterogeneous Catalysts: complex materials at the atomic level.

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Plenary lecture given by Prof. Hajo Freund (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany) on September 11, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.

Plenary lecture given by Prof. Hajo Freund (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany) on September 11, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.

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Models for Heterogeneous Catalysts: complex materials at the atomic level.

  1. 1. Models for Heterogeneous Catalysts: Complex Materials at the Atomic Level Hajo Freund Fritz Haber Institute of the Max Planck Society Program  Introduction  4 conceptual studies : nanoparticles/ amorphous silica/confined space strong metal support interaction
  2. 2. Introduction: Catalysis Activation Energy Energy without Catalyst With Catalyst E* ∆E
  3. 3. Introduction: Catalysis at the Atomic Scale The Active Center Heterogeneous Catalysis Homogeneous Catalysis Enzymatic Catalysis
  4. 4. Ammonia Synthesis Technical Plant Fritz Haber 1868 -1934 Nobel Price 1918World Production: 160 Mio t/a
  5. 5. Surface Science Models Energy Profile G. Ertl, Catal.Rev.Sci.Eng. 21(1980), 201 Gerhard Ertl b. 1936 Nobel Price 2007 Fe(111)
  6. 6. Mustertext Heterogeneous Catalysis J. Sauer, H.-J. Freund; Catal Lett 145, 109 (2015)
  7. 7. Thin Oxide Film Systems Scenarios H.-J. Freund; Perspective J. Amer.Chem.Soc. 138, 8985 (2016)
  8. 8. Thin Oxide Film Systems Area 1 Identification of the Active Site at the Metal-Oxide Interface in supported nanoparticle systems
  9. 9. STM Imaging Nano-Particles at the Rim Thanks to Markus Heyde and Shamil Shaikhutdinov W.-D. Schneider, M. Heyde, HJF, Chem.Eur.J. accepted (111) facet (100) facet (a) b(b) K. H. Hansen et al. Phys. Rev. Lett. 83, 4120 (1999)
  10. 10. Thin versus Thick Oxide Films Density functional calculations D. Ricci, A. Bongiorno, G. Pacchioni , U. Landmann, Phys. Rev. Lett. 97, 036106 (2006)
  11. 11. STM – MgO(001)/Ag(001) Au nanoparticles on MgO thin films Images: 30x30 nm², It=10 pA, US=+500 mV. 3 ML MgO(001) anneal to 210 K anneal to 300 K 8 ML MgO(001) M. Sterrer, T. Risse, M. Heyde, H.P. Rust, HJF, Phys. Rev. Lett. 96, 206103 (2007)
  12. 12. Au on MgO / Ag(001) Low Temperature STM Au18 Cluster • Experimental signature X. Lin, N.Nilius, HJF, M. Walter, P. Frondelius, K. Honkola, H.Häkkinen, Phys. Rev. Lett., 102, 206801 (2009) 4-
  13. 13. Au on MgO / Ag(001) Low Temperature STM Harmonic oscillator model: Eigenstates 1S 2S 3S 1P 2P 1P 2P 1D 2D 1D 2D 1F 1G 1G 1F Energy Angular momentum quantum number 0 1 2 3-4 -3 -1 Au18 -4 Au14 -2 Au8 -2 -2 4
  14. 14. Properties of perimeter atoms Au islands on MgO/Ag(001) films 5 K – STM 10 × 10 nm2 Parameterized DFT-approach StructureModel Theory: Pekka Koskinen, Hannu Häkkinen, Nanoscience Center, University of Jyväskylä X. Lin, N.Nilius, M.Sterrer, P. Koskinen, H. Häkkinen, HJF , Phys. Rev. B81, 153406 (2010)
  15. 15. Properties of perimeter atoms Au islands on MgO/Ag(001) films STM conductance imaging (10 × 10 nm2) X. Lin, N.Nilius, M.Sterrer, P. Koskinen, H. Häkkinen, HJF, Phys. Rev. B81, 153406 (2010)
  16. 16. Vibrations at Surfaces 1 internal vibrational mode 3 frustrated translational modes 2 frustrated rotations Individual CO Molecule on a Surface N. V. Richardson and N. Sheppard, Vibrational Spectroscopy of Molecules on Surfaces, in Plenum Press, 1987, Ed. J. T. Yates, T. E. Madey
  17. 17. CO adsorption on planar islands Au on MgO/Ag(001) films 45 mV, 10 × 10 nm2 -45 mV Contrast in d2I/dV2 images relates to inelastic transport channels Maximum signal at ±45 mV suggests excitation of CO hindered rotation Au island CO MgO +45 mV Second derivative images X. Lin, B. Yang, M. Brown, M. Sterrer, T. Risse, N. Nilius, et al. HJF;J. Amer. Chem. Soc. 132 7745 (2010)
  18. 18. Model Catalysts Isophorone at the Rim Ch. Stiehler, F. Calaza, W.-D. Schneider, N. Nilius, H.-J. Freund, Phys. Rev. Lett. 115, 0368041 (2015) C9H14O
  19. 19. Model Catalysts Physisorption vs. Chemisorption Ch. Stiehler, F. Calaza, W.-D. Schneider, N. Nilius, H.-J. Freund, Phys. Rev. Lett.115, 0368041 (2015)
  20. 20. Influence of 2D3D Morphology on Reactvity Carbon Dioxide Activation
  21. 21. Carbon Dioxide Activation Electron Attachment Energetics CO2 -: - 0.6 eV, (CO2)2 -: + 0.9 eV H.-J. Freund, M.W. Roberts, Surf.Sci. Rep. 25, 225 (1996) A. Stamatovic, K. Stephan, T.D. Märk; Int. J. Mass Spectr. 63 37 (1985) R.N. Compton, P.W. Reinhardt, C.D. Cooper; J. Chem. Phys. 63, 3821 (1975) (CO2)2 + e-  (CO2)2 - A.R. Rossi and K.D. Jordan, J. Chem. Phys. 70 (1979) 4422
  22. 22. Model Catalysts Carbon Dioxide Activation 0.3V 0.3VN=182 N=190 0 1 2 3 4 0.0 0.5 1.0 1.5 2.0 Pristine Cluster Cluster with Molecules FittedPeakPositionsU[V] Quantum number n 0 1 2 3 4 0.0 0.1 0.2 0.3 0.4 Quantum number n m* Cl+mol = 0.7 m* Cl ∆U = UCl+mol – Uprist F. Calaza, C. Stiehler, Y. Fujimori, M.Sterrer, S. Beeg, M. Ruiz-Oses, N. Nilius, M. Heyde, T. Parviainen, K. Honkala, H. Häkkinen, H.-J. Freund; Angew. Chem.Int. Ed. 54,12484 (2015); Ch. Stiehler, F. Calaza, W.-D. Schneider, N. Nilius, H.-J. Freund, Phys. Rev. Lett.115, 0368041 (2015)
  23. 23. Carbon Dioxide Activation Isotopic Labeling in IRAS Spectra 1100 1200 1300 1400 1500 1600 13 CO2 / 2ML MgO C 18 O2 / 2ML Mg 18 O CO2 / 2ML Mg 18 O Absorbance/a.u. wavenumber / cm -1 1259 1275 1295 CO2 / 2ML MgO 0.0004 F. Calaza, C. Stiehler, Y. Fujimori, M.Sterrer, S. Beeg, M. Ruiz-Oses, N. Nilius, M. Heyde, T. Parviainen, K. Honkala, H. Häkkinen, H.-J. Freund; Angew. Chem. Int. Ed. 54,12484 (2015)
  24. 24. IRAS 2 ML MgO(001)/Ag(001) samples recorded after a saturation dose of CO2 at 223 K. Au was deposited at 100 K and  the samples subsequently annealed to the indicated temperature prior to CO2 adsorption. Carbon Dioxide Activation C.P. O´Brien, K.-H. Dostert, M. Hollerer, C. Stiehler, F. Calaza, S. Schauermann, S. Shaikhutdinov,, M. Sterrer, HJF, Farad. Disc. 188, 309 (2016)
  25. 25. Carbon Dioxide Activation STM STM images of (a) Au deposited on 2 ML MgO(001)/Ag(001) at 77 K, and subsequent annealing to 343 K (b), 400 K  (c) and 500 K (d). All images were taken at 77 K. (a)‐(c) 25 nm  25 nm; (d) 50 nm  50 nm. Ubias = +(0.5‐0.75) V. It = 30 pA. The inset show height C.P. O´Brien, K.-H. Dostert, M. Hollerer, C. Stiehler, F. Calaza, S. Schauermann, S. Shaikhutdinov,, M. Sterrer, HJF, Farad. Disc. 188, 309 (2016)
  26. 26. Model Catalyst Concepts Dispersed Metal Catalyst Models: Dopants Metal particles Metal single crystal Oxide film Dopants
  27. 27. Mo-donors and the tip influence Mo-doped CaO films on Mo(001) Filled 25 ML CaO grown on Mo(001) (5050 nm2, 4.5 V) Topo-graphic and dI/dV image of charging rings. Adsorption of an O2 suppresses(118 nm2, 2.5eV) STM images of 25 ML CaO annealed to the given temperatures (3030 nm2, 2.6 V) On 50 ML thick films, the diameter is larger due to the bad dielectric screening (30x30 nm2, 4.4.eV) Y. Cui, N. Nilius , H.-J. Freund, S. Prada, L. Giordano, G. Pacchioni, Phys.Rev. B 88, 205421 ( 2013)
  28. 28. Mo-donors and the tip influence Mo-doped CaO films on Mo(001) Filled Y. Cui, S. Tosoni, W.-D. Schneider, G. Pacchioni, N. Nilius , H.-J. Freund, Phys. Rev. Lett. 114, 016804 (2015)
  29. 29. Growth behavior of gold Mo-doped CaO films on Mo(001) Pristine CaO film 60 ML plus 0.8 ML Au Mo-doped CaO film 60 ML plus 2% Mo 0.8 ML Au 4040 nm2  Crossover from 3D to 2D growth behavior for Au after Mo doping  2D Au islands display stripe pattern due to Moiré structure with CaO surface  3D growth is restored after co-doping with Li (X. Shao, N. Nilius, HJF; JACS 134, 2432 (2012)) X. Shao, S. Prada, L. Giordano, G. Pacchioni, N. Nilius, H.-J. Freund , Angew.Chem. Int. Ed. 50, 11525 (2011)
  30. 30. Internal Structure of the Au Islands Mo-doped CaO films on Mo(001) Moiré pattern in pseudo 3D representation: 25ML thick CaO Film, Mo doped Vs=4.0 V; 15 pA. Left: 40x40 nm; right: 11x11nm
  31. 31. Thin Oxide Film Systems Area 2 Modeling amorphous silica supports
  32. 32. Film Preparation and Characterization Correlation between Structure and IR Spectra B. Yang, R. Wlodarczyk, M. Sierka, J. Sauer et al., Phys. Chem. Chem. Phys. 14 (2012) 11344
  33. 33. Film Structure and Scattering Crystalline and Vitreous Silica Films B. Yang, R. Wlodarczyk, M. Sierka, J. Sauer et al., Phys. Chem. Chem. Phys. 14 (2012) 11344 C. Buechner, L. Lichtenstein, X. Yu, A. Boscoboinik, B. Yang , R. Wlodarczyk, M. Heyde. S. Shaikhutdinov, J. Sauer, H.-J. Freund; Chem. Eur. J. 20, 1 (2014)
  34. 34. Scanning Probe: nc-AFM vs. STM Chemical Sensivity L. Lichtenstein, M. Heyde, H.-J. Freund, J. Phys. Chem. C 116 (2012) 20426 all images: 3.5 x 3.5 nm²
  35. 35. Scanning Probe: nc-AFM vs. STM Simultaneous Imaging of Si and O L. Lichtenstein, M. Heyde, H.-J. Freund, J. Phys. Chem. C 116 (2012) 20426
  36. 36. Crystal-Glass Transition Silica Interface - Atomic Model L. Lichtenstein, M. Heyde, H.-J. Freund, Phys. Rev. Lett. 109 (2012) 106101 STM, 12.3 x 7.0 nm², VS = 2 V, IT = 100 pA
  37. 37. liquidAFM Setup 2D Silica on Ru(0001) K. M. Burson, L. Gura, C. Büchner, B. Kell, M. Heyde, H.-J. Freund  Film production in UHV  Rapid transfer to liquid (<45s)  Pure water / NaCl solution  High-frequency cantilevers fair = 1.0-1.3 MHz fwater = 400 - 475 kHz  Amplitude modulation mode
  38. 38. liquidAFM versus LT-UHV-ncAFM-STM 2D Silica on Ru(0001) K. M. Burson, L. Gura, C. Büchner, B. Kell, M. Heyde, H.-J. F. ;Appl. Phys. Lett. 108, 201602 (2016)
  39. 39. Substrate Changed – Structure Retained 2D Silica Transfer C. Büchner, Z.-J. Wang, K. M. Burson, M.-G. Willinger, M. Heyde, R. Schlögl, H.-J. Freund, ACS Nano 10 ,7982 (2016)
  40. 40. Thin Oxide Film Systems Area 3 3 Investigating adsorption and chemical reactions in confined space
  41. 41. Chemistry in Confined Space Crystalline-Vitreous Interface in 2D Silica X. Yu, E. Emmez, Q Pan, B. Yang, S. Pomp, W.E. Kaden, M. Sterrer, S. Shaikhutdinov, HJF, I. Goikoetxea, R. Wlodarczyk, J. Sauer, Phys. Chem. Chem. Phys.,18,3755 (2016) IRA spectra measured in 2 × 10−6 mbar CO (a−g) and 10−5 mbar CO (h) at the indicated temperatures. Each spectrum takes 12 s. Total: 6-min exposure.
  42. 42. Experimental Setup SMART R. Fink et al. J. Elec. Spec. Rel. Phen. 84, 231 (1997) Sample e- gun Mirror Transfer optics Energy filter Projector Screen X-rays • Energy resolution: 180 meV • Lateral resolution: 2.6 nm (LEEM), 18 nm (XPEEM) • Temperature range: 100 ÷ 2000 K; • Pressure range: 10-11 ÷ 10-5 mbar; • Photon range: 80 ÷ 1500 eV • surface sensitive • temporal evolution • multi-method: microscopy-diffraction-spectroscopy SMART: Spectro-microscope with aberration correction for many relevant techniques
  43. 43. Chemistry in confined space Intercalation using a vitreous SiO2 bilayer CO intercalation
  44. 44. Thin Oxide Film Systems Area 4 Modeling Strong Metal Support Interaction
  45. 45. History and Evidences Strong Metal Support Interaction (SMSI) A.K.Datye, D.J. Smith, Langmuir 1988, 4, 827-830 Short History of SMSI: F. Solymosi in Cat. Rev. 1, 233-255 (1968) 1957 G.M. Schwab et al.: Electronic properties of the support are important. 1961 Z.G, Szabo, F. Solymosi: Concrete examples of Ni on various supports of doped oxides 1978 S.J. Tauster et al.: Reduction of metal supresses chemisorption through electronic interaction 1983 J. Dumesic et al./ G. Haller et al. Migration of support species onto the particle 1984 J.M. Hermann: Transport measurements to infer electronic interaction F. Solymosi J. Catal. „Letter to the Editor“ 94, 581 (1985) The term SMSI as it is used today is, indeed, somewhat missleading!
  46. 46. Pt/Fe3O4(111): SMSI Effect Morphology and Structure CO TPD Fe3O4(111) FeO(111) Pt 100 nm x 100 nm 80 nm x 80 nm Wadh = 3.8 ± 0.1 J/m2 (~3.1 J/m2 for Pd/Al2O3, Fe3O4) Encapsulation of Pt particles by a FeO(111) film at elevated temperatures driven by high adhesion energy. Qin et al., J. Phys. Chem. C 112 (2008) 10209; Qin et al., J. Phys. C 21 (2009) 134019
  47. 47. FeO(111)/Pt(111) Structure Deposition ~1 ML Fe in UHV Oxidation @ 1000 K in 10-6 mbar O2 Lattice mismatch ~10%: 2.78 Å (Pt) vs 3.11 Å (FeO) Vurens et al., Surf. Sci. 201 (1988) 129; 268(1992) 170; Galloway et al., Surf. Sci. 298 (1993) 127; Kim et al., Surf. Sci. 416 (1998) 68; Ritter et al., Phys. Rev. B 57 (1998) 7240 150 nm x 150 nm
  48. 48. CO Oxidation on FeO(111)/Pt(111) Reactivity Batch reactor: 40 mbar CO + 20 mbar O2 balanced by He Ultrathin FeO(111) film is much more active than Pt(111) and nm-thick Fe3O4(111) films. Sun et al., J. Catal. 266 (2009) 359
  49. 49. FeO(111)/Pt(111) Reconstruction Density Functional Theory and STM See also Grönbeck et al., JACS (2009) for 2 ML MgO(100)/Ag(100). EPR evidence for O2 - species! (Risse et al. Angew.Chem. (2011)) Charge transfer + Structural flexibility Y.-N. Sun, L. Giordano, J. Goniakowski, M. Lewandowski, Z.-H. Qin, C. Noguera, S. Shaikhutdinov, G. Pacchioni, HJF, Angew. Chem. 122, 4520 (2010)
  50. 50. High Angle Annular Dark Field (HAADF)-STEM Images Strong Metal Support Interaction The nature of the interface between support and particle! Pt(111) Fe3O4(111) Pt M. Willinger*, W. Zhang, O. Bondarchuk, S. Shaikhutdinov*, H.-J. Freund, R. Schlögl ; Angew. Chem.Int.Ed. 53, 5998 (2014)
  51. 51. EELS and STEM Strong Metal Support Interaction How does the material migrate ? M. Willinger*, W. Zhang, O. Bondarchuk, S. Shaikhutdinov*, H.-J. Freund, R. Schlögl; Angew. Chem. Int.Ed. 53, 5998 (2014)
  52. 52. High Resolution TEM Strong Metal Support Interaction M. Willinger*, W. Zhang, O. Bondarchuk, S. Shaikhutdinov*, H.-J. Freund, R. Schlögl; Angew. Chem.Int.Ed. 53, 5998 (2014) FeO(111)
  53. 53. Summary Models for Heterogeneous Catalysts: Complex Materials at the Atomic Level  The rim of a supported nanoparticle may be identified as the active site for a chemical reaction  An amorphous silca film may prepared and characterized at the atomic level. Transferability to other substrates is possible.  Underneath a silica film reactions in confined space may be studied and interesting spatio-temporal phenomena may be observed.  Strong Metal Support Interaction may be studied via thin oxide films and its transformation under reaction conditions may be modelled.
  54. 54. T H A N K S Collaborations R. Schloegl / FHI C. Campbell / U Washington J. C. Hemminger / UC Irvine C. Henry / Luminy M.-P. Pileni / Paris M. Bowker / Cardiff T. Oyama / Virginia, Tokyo M. Schmal / Rio de Janeiro H. Niehus / HU Berlin P. Stair / Northwestern H. Gao / Beijing F. Zaera / UC Riverside K. Hermann / Berlin M. Wilde / Tokyo K. Fukutani / Tokyo K. Asakura / Sapporo E. Bauer, A. Pavlovska / Arizona C. Friend, R. Madix/ Harvard W. Huang / Hefei E. Giamello / Turino M. Asscher / Jerusalem
  55. 55. Thanks The Department

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