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Calculated ammonia synthesis rates
400 C, 50 bar, H2:N2=3:1, 5% NH3
Logatottir, Rod, Nørskov, Hammer, Dahl, Jacobsen, J. Catal. 197, 229 (2001)](https://image.slidesharecdn.com/catalysisnorskov0515021-240227111952-01b1d058/75/Heterogeneous-Catalysis-Opportunities-and-Challenges-11-2048.jpg)
![Single crystal microcalorimerty
Metal coverage [ML]
0 1 2 3 4 5 6 7 8
Heat
of
adsorption
[kJ/mol]
0
50
100
150
200
250
300
350
400
Cu/MgO
Ag/MgO
Pb/MgO
Larsen, Starr, Campbell, Chem.Thermodyn. 33, 333 (2001)
Brown, Kose, King, Chem. Rev. 98, 797 (1998).](https://image.slidesharecdn.com/catalysisnorskov0515021-240227111952-01b1d058/75/Heterogeneous-Catalysis-Opportunities-and-Challenges-23-2048.jpg)
![Methane activation on Ni/Ru
Ni Coverage [ML]
0 1 2
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sticking
probability
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1e-7
2e-7
3e-7
4e-7
5e-7
Thermal dissociation of CH4
at T = 530 K
Egeberg, Chorkendorff, Catal. Lett. 77, 207 (2001)](https://image.slidesharecdn.com/catalysisnorskov0515021-240227111952-01b1d058/75/Heterogeneous-Catalysis-Opportunities-and-Challenges-28-2048.jpg)
Heterogeneous Catalysis - Opportunities and Challenges
- 1. Heterogeneous Catalysis Opportunities andchallenges • Challenges –Societal needs –Developing the basic understanding • Opportunities –Designing at the nano-scale J. K. Nørskov Center for Atomic-scale Materials Physics Technical University of Denmark norskov@fysik.dtu.dk
- 2. Challenges I Jens Rostrup-Nielsen:XVII Sympósio Iberoamericano de Catálisis, July 16-21, 2000 Dream reactions waiting for a catalyst:
- 3. Dreaming on …. •Heterogeneous catalysts for assymmetric synthesis • Photolytic water splitting (hydrogen economy) • Biomimetics, synthetic enzymes • Non-thermal processes in general (e.g. electro- and photocatalysis) • … See: E. Derouane, CATTECH 5, 226 (2001) Challenges II
- 4. Challenges III The scienceof heterogeneous catalysis: • A comprehensive scientific basis – Much has been done – Much more is needed (oxides, size effects, photocatalysis, electrocatalysis, relation to homogeneous and enzyme catalysis …) • Making the insight useful! – The ultimate test
- 5. Opportunities - design atthe nano-scale • Rational catalyst design - Discovery on the basis of insight • Data-driven methods - Accelerated discovery by access to large amounts of data • Bio-inspired catalysis
- 6. Rational catalyst design 1.What determines the catalytic activity/selectivity/lifetime ? 2. How can we affect it? - We have tremendous new possibilities
- 7. Ammonia synthesis N2+3H2 2NH3 Ozakiand Aika, Catalysis 1 (Anderson and Boudart, Ed.)
- 8. Ammonia synthesis overRu Ru(0001) step Logadottir, Nørskov
- 9. Steps do everything Dahl,Logadottir, Egeberg, Larsen, Chorkendorff, Törnqvist, Nørskov, Phys.Rev.Lett. 83, 1814 (1999) Au decorates steps: Hwang, Schroder, Gunther, Behm, Phys. Rev. Lett. 67, 3279 (1991)
- 10. Logatottir, Rod, Nørskov,Hammer, Dahl, Jacobsen, J. Catal. 197, 229 (2001) The Brønsted-Evans-Polanyi relation
- 11. - 0 . 8 - 0 . 40 . 00 . 40 . 8 [ E - E ( R u ) ] ( e V / N 2 ) 1 0 - 5 1 0 - 4 1 0 - 3 1 0 - 2 1 0 - 1 1 0 0 1 0 1 T O F ( s - 1 ) F e M o R u C o N i O s Calculated ammonia synthesisrates 400 C, 50 bar, H2:N2=3:1, 5% NH3 Logatottir, Rod, Nørskov, Hammer, Dahl, Jacobsen, J. Catal. 197, 229 (2001)
- 12. Interpolation in theperiodic table Jacobsen, Dahl, Clausen, Bahn, Logadottir, Nørskov, JACS 123 (2001) 8404.
- 13. Jacobsen, Dahl, Clausen,Bahn, Logadottir, Nørskov, JACS 123 (2001) 8404. Interpolation in the periodic table
- 14. Jacobsen, Dahl, Clausen,Bahn, Logadottir, Nørskov, JACS 123 (2001) 8404. Measured ammonia synthesis rates 400 C, 50 bar, H2:N2=3:1
- 15. Data driven methods •High throughput screening – Direct testing of many catalysts, fast, efficiently • Data mining – Correlating catalytic activity/selectivity/ durability to descriptors that can be tabulated
- 16. The object ofthe game… • Find sets of descriptors {Dik} of solid materials Mi , and a mathematical model F such that Aij being the Turn Over Frequency of Mi as catalyst for the reaction j at operationg conditions Cj one has: • Identify ranges of Dik that maximize F • Screen Databases of Materials Properties before screening real materials • Better if one descriptor is sufficient, but do not take it for granted • Much better if F has a sound physical basis • Adsorbate/substrate bond strengths should provide good descriptors according to the Sabatier principle j ik j i ij C D F C M A , , Using DFT calculations in the search of prospective catalysts H. Toulhoat and P. Raybaud Workshop Catalysis from First Principles Vienna 02/02
- 17. Periodic Trends forE MC in Fm-3m (NaCl) carbides Sc Cr V Mn Co Ni Y Zr Tc Ru Rh Pd Ta Re Os Ir Ti Fe Cu Nb Mo La Hf W Pt Au Ag 0 20 40 60 80 100 120 140 160 E MC YY/PAW/GGA/SP (kJ/mol) Using DFT calculations in the search of prospective catalysts H. Toulhoat and P. Raybaud Workshop Catalysis from First Principles Vienna 02/02
- 18. Adsorption of C2H4100K : di-s bound : p bound : No ads. Sc Ti V Cr Mn Fe Co Ni Cu Y Zr Nb Mo Tc Ru Rh Pd Ag La Hf Ta W Re Os Ir Pt Au Ru Rh Fe Cr W Ni Ta Pt (Diss.) Ag Au Cu Pt(molec) Pd y = 6,267x - 287,99 R2 = 0,894 y = 1,9625x - 29,758 R2 = 0,791 0 100 200 300 400 500 600 0 20 40 60 80 100 120 140 E MC YY (@NaCl/PAW/GGA/SP) (kJ/mol) Qads exp. C2H4/M (kJ/mol) • E MC @ Fm-3m carbides is rather consistent with simple chemisorption models • Onset of dissociative chemisorption as MC bond strength increases Using DFT calculations in the search of prospective catalysts H. Toulhoat and P. Raybaud Workshop Catalysis from First Principles Vienna 02/02
- 19. Re3Ir Ir3Re Ir3Cu Cu3Ir Cu Pd Ru Ir Pt Os Re Co Ni 1,E+00 1,E+01 1,E+02 1,E+03 1,E+04 1,E+05 10 12 1416 18 20 22 24 26 28 30 E MC YY (kCal.mol-1) Rate in Hydrogenation of C6H6 (s -1 ) TOF@30°C (M/Al2O3 Brunelle et al., 1977) V théor. • The experimental Alloying effects is correctly predicted Using DFT calculations in the search of prospective catalysts H. Toulhoat and P. Raybaud Workshop Catalysis from First Principles Vienna 02/02
- 20. Getting data/descriptors • Structure(in situ) • Spectroscopy (in situ) • Surface thermochemistry • Calculations • … There is a large need for systematic data - and for good descriptors
- 21. Structure-activity Correlation Hydrodesulfurization ofthiophene 1.5 10 0.5 0 0 1 2 3 Number of Co edge atoms (x1020/g catalyst) HDS activity (x10 2 /mol/g/h) Topsøe, Clausen, Massoth Hydrotreating Catalysis, Science and Technology (Anderson and Boudart (Eds.), Springer (1996).
- 22. Descriptors from spectroscopy COTPD shift Core level shift Goodman and Rodriguez, Science 279 (1992) 897
- 23. Single crystal microcalorimerty Metalcoverage [ML] 0 1 2 3 4 5 6 7 8 Heat of adsorption [kJ/mol] 0 50 100 150 200 250 300 350 400 Cu/MgO Ag/MgO Pb/MgO Larsen, Starr, Campbell, Chem.Thermodyn. 33, 333 (2001) Brown, Kose, King, Chem. Rev. 98, 797 (1998).
- 24. Descriptors from DFT Correlation betweenadsorption energies and activation barriers and the d-band center Mavrikakis , Hammer, Nørskov Phys. Rev. Lett. 81, 2819 (1998)
- 25. CO tolerance ofPt alloy anodes for PEM fuel cells Pt M -0,5 0,0 0,5 1,0 1,5 2,0 Au Ir Ag Pd Rh Ru Cu Ni Co Fe Pt E CO , eV - d , eV Substrate M -0,2 0,0 0,2 0,4 0,6 0,8 1,0 0,0 0,2 0,4 0,6 0,8 1,0 Measured overages of CO on the alloy electrodes with 100 ppm CO/H2 M. Watanabe et al., Phys. Chem. Chem. Phys. 3 (2001) 306 1- co Calculated changes in CO adsorption energy S. Gottesfeld et al., J. Electrochem. Soc. 148 (2001) A11. Christoffersen, Liu, Ruban, Skriver, Nørskov, J.Catal. 199, 123 (2001)
- 26. How can thed-band center be changed? Calculated d band shifts: Ruban, Hammer, Stoltze, Skriver, Nørskov, J.Mol.Catal. A 115, 421 (1997) Overlayer Host
- 27. Methane activation Bengaard, Rostrup-Nielsen,Nørskov b Transition state for CH4 dissociation on Ni(211)
- 28. Methane activation onNi/Ru Ni Coverage [ML] 0 1 2 Initial sticking probability 0 1e-7 2e-7 3e-7 4e-7 5e-7 Thermal dissociation of CH4 at T = 530 K Egeberg, Chorkendorff, Catal. Lett. 77, 207 (2001)
- 29. Lessons from biology •Catalysis at ambient temperature and pressure • Extreme selectivity • Direct coupling of energy into the important reaction coordinate (non-thermal catalysis)
- 30. Nitrogenase 8e 8H N2 2 3H 2NH nitrogenase ATP FeP + 2 (MgATP) MoFeP 1 k 1 - k FeP 2 (MgATP) MoFeP 4 k 2 k nucleotide replacement ATP cleavage electron transfer ox FeP 2 (MgADP) + MoFeP 3 k 3 - k ox FeP 2 i ) P (MgADP, MoFeP reduction complex formation complex dissociation - 4 AlF ADP Fe protein Fe protein MoFe protein 4Fe-4S cluster P-cluster FeMo cofactor Burgess, Lowe, Chem. Rev. 96, 2983 (1996) Schindelin, Kisker, Schlessman, Howard, Rees, Nature 387, 370 (1997)
- 31. N2 hydrogenation onFeMoco Rod, Nørskov JACS 122, 12751 (2000)
- 32. The Fe Proteincycle 1) 2) 3) 4) E E E MoFe protein FeMoco P-cluster Fe protein 4Fe-4S cluster ATP ADP 2 4 HPO See also: Spee, Arendsen, Wassnik, Marrit, Hagen, Haaker, FEBS Lett. 432, 55 (1998)
- 33. Comparing the FeMocoand Ru(0001) Rod, Logadottir, Nørskov J.Chem.Phys. 112, 5343 (2000)
- 34. Status • Well developedbasic understanding – theory-experiment • Beginning to be able to use it directly in catalyst design • Some activity-descriptor correlations • Host of new in situ methods for catalyst characterization • New very powerful screening methods • We have a starting point which is radically different from the situation 5 or 10 years ago!
- 35. Moving forward • Morebasic understanding –theory-experiment • Integration of the conceptual framework for heterogeneous, homogeneous and enzyme catalysis • More systematic data (descriptors) • Better synthesis methods • Better coupling of catalyst design and process engineering • INTEGRATION
- 36.