Design of catalysts and photocatalysts: fascinating strategies playing with structures at the nanoscale. Paolo FORNASIERO

Transcription

1 Design of catalysts and photocatalysts: fascinating strategies playing with structures at the nanoscale Paolo FORNASIERO SESTO, June 27, 2016

2 Outline Introduction Nanocrystals and enbedded catalysts Photocatalysts Fe 2 O 3 TiO 2 C- based hybrids

3 Energy and quality of life Energy consumption Human development index

4 The end of the cheap oil

5 Global density of pollution

6 Crisis Danger Opportunity

7 Black Box vs Catalyst Design ChemPhysChem 14, 2013, 3869

8 Black Box vs Catalyst Design

9 Catalyst Design ChemPhysChem 14, 2013, 3869

10 Nanotechnology and catalysis: tandem catalysis Yusuke Yamado, et al. Nature Chemistry 3, 2011, 372

11 Monodispersed nanocrystals as model catalysts 4.0 nm 8.5 nm 12.0 nm 4-12 nm 2.5 nm 3.7 nm 6.3 nm nm 1.6 nm 2.3 nm 2.9 nm nm Science 341, 2013, 771

12 Role of the support

13 Monodispersed nanocrystals: CO oxidation CO + ½O 2 CO 2 CO + O 2 in He, GHSV ~45, ,000 ml g -1 h -1 no size dependenc e there IS size dependenc e Science 341, 2013, 771

14 Monodispersed metal crystals on CeO 2 as model catalysts CO + ½O 2 CO 2 CO + O 2 in He, GHSV ~45, ,000 ml g -1 h -1 Science 341, 2013, 771

15 Tailoring nanostructured materials encapsulation of preformed metal nanoparticles into MO x through different methodologies ChemSusChem 3, 2010, 24

16 Core shell structures in catalysis PROX photocatalysis NH 3 decomposition Chem. Mater. 22, 2010, 4335 J. Phys. Chem. A 114, 2010, 3916 ChemCatChem 2, 2011, 1096 Au@TiO 2 Pt@ZnO Catal. Lett. 144, 2014, 1939 J. Mater. Chem. A, 2, 2014, 19509

17 2 CORE-SHELL STRUCTURES

18 Dispersible structures MUA-Pd NPs MUA: 11-Mercapto Undecanoic Acid Pd core size: 1.8 ± 0.2 nm THF Hydrolysis conditions: THF + 30 eq H 2 O (120 mol vs Ce) in 4 h = dodecanoic acidmodified Ce(IV) tetrakis(decyloxide) Dispersible in CH 2 Cl 2, toluene, hexane J. Am. Chem. Soc. 142, 2010, 1402 ChemSusChem 5, 2012, 140

19 2 based anode in Solid Oxides Fuel Cells - all solid state high Temperature ( C) - high power densities Stable materials! - possibility to use hydrocarbon fuels

20 2 based anode in Solid Oxides Fuel Cells ACS Catal. 3, 2013, 1801

21 Catalytic combustion of methane Power generation Exhaust after-treatments: VOCs removal Efficient and cost-effective Limitations: Cold start Low speed driving Methane abatement at low temperature

22 Catalytic combustion of methane Pd-based catalysts CH 4 + 2O 2 CO 2 + 2H 2 O 2 active phases: PdO and Pd PdO Pd High T Al 2 O 3 Al 2 O 3 Low T Stable at low temperature Stable at high temperature High specific activity Lower specific activity Equilibrium depends on: O 2 pressure Redox properties of the support

23 CH 4 Oxidation: Transient Behavior PdO Pd PdO decomposition occurs Pd is active at high temperature Pd PdO formation is kinetically limited by nucleation PdO Pd(5%)/La-Al 2 O 3 P. Gélin, M. Primet, Applied Catalysis B: Environmental 39, 2002, 1 37

24 CH 4 Oxidation: Transient Behavior PdO Pd PdO decomposition occurs Pd is active at high temperature Pd PdO formation is kinetically limited by nucleation PdO Pd(5%)/La-Al 2 O 3 P. Fornasiero et.al Chem.Rev ,

25 Supramolecular catalyst based on 2 single units HAADF-STEM Agglomeration of 2 to give ordered superstructures TOMOGRAPHY Science, 337, 2012, 713

26 Supramolecular catalyst based on 2 single units Science, 337, 2012, 713

27 Supramolecular catalyst based on 2 single units CH 4 + 2O 2 CO 2 + 2H 2 O Science, 337, 2012, 713

28 Supramolecular catalyst based on 2 single units Science, 337, 2012, 713

29 Supramolecular catalyst : effect of water Dry Wet 0.5% CH 4, 2.0% O 2, 15% H 2 O (if present), Ar balance, O 2 /O 2(stoich) =2, GHSV = ml g -1 h -1 ChemCatChem, 7, 2015,

30 Supramolecular catalyst : effect of water at 600 C No water 15% water Pd Conditions: 0.5% CH 4, 2.0% O 2, Ar balance, GHSV= h -1. ChemCatChem, 7, 2015,

31 Dry conditions, 600 C Wet conditions, 600 C CH 4 + O 2 CO 2 + H 2 O CH 4 + O 2 CO 2 + H 2 O Ce III CeO 2 Ce III CeO 2 PdO Pd Ce III Ce III O 2 OH Ce III Ce III OH CeO 2 Pd OH Ce III Ce III OH Al Al 2 O 3 Al 2 O 3 Reduction of PdO to Pd Increase in population of OH Wet aging reduces Pd accessibility ChemCatChem, 7, 2015,

32 Model Catalysts: 2 /graphite Model catalyst Conductive support Different interactions Lower calcination T XPS SRPES Synchrotron Radiation PhotoEmission Spectroscopy

33 Model planar H-ZrO 2 -supported Pd@CeO 2 Plan-view Cross Sectional view Calcined at 500 C. S. Zhang, C. Chen, M. Cargnello, P. Fornasiero, R. Gorte, G. Graham, X. Pan, Nature Communications 2015

34 Model planar H-ZrO 2 -supported Pd@CeO 2 : heating at 550 Time 0 + C 20 min +26 min a b c d d e Figur e 7 550C f + 30 min + 31 min + 37 min S. Zhang, C. Chen, M. Cargnello, P. Fornasiero, R. Gorte, G. Graham, X. Pan, Nature Communications 2015

35 Environmental TEM: stability of 2 units C 800 C Ceria Palladium Ceria Palladium SiOx SiOx Pd 2+ CeOx S. Zhang, C. Chen, M. Cargnello, P. Fornasiero, R. Gorte, G. Graham, X. Pan, Nature Communications 2015

36 Today Challenges Hydrogen Economy CO 2 to Solar Fuels Depollution Green Synthesis

37 Band position relative to water redox potential R. M. N. Yerga, M. C. A. Galván, F. del Valle, J. A. V. de la Mano, J. L. G. Fierro, ChemSusChem 2009, 2, 471

38 Fe 2 O 3 polymorphs for photo-assisted H 2 production Advanced Functional Materials 2014, 24,

39 Fe 2 O 3 polymorphs for photo-assisted H 2 production Solar-to-Fuel Efficiency 0.86% 0.48% 0.16% Advanced Functional Materials 2014, 24,

40 TiO 2 nanocrystals for photo-assisted H 2 production J. Am. Chem. Soc 134 (2012),

41 TiO 2 nanocrystals for photo-assisted H 2 production high volumes of hydrogen (up to 2.1 mmol h 1 g 1 ) under simulated solar illumination. The {101} facets of anatase are more active than the {001}. J. Am. Chem. Soc 134 (2012),

42 TiO 2 nanocrystals for photo-assisted H 2 production Proc.Natl.Acad.Sci., 113 (15),

43 TiO 2 nanocrystals for photo-assisted H 2 production Proc.Natl.Acad.Sci., 113 (15),

44 TiO 2 nanocrystals for photo-assisted H 2 production Proc.Natl.Acad.Sci., 113 (15),

45 TiO 2 nanocrystals for photo-assisted H 2 production Proc.Natl.Acad.Sci., 113 (15),

46 TiO 2 nanocrystals : Ultrafast transient absorption spectroscopy 50 fs ultraviolet (4.0 ev) pump pulse Proc.Natl.Acad.Sci., 113 (15),

47 2 : a modular approach CNT-ox M = Pd, Pt; oxide = TiO 2, ZrO 2, CeO 2 MWNTs MWNTs@TiO 2 M/MO 2 M hydrolysis MWNTs@ZrO 2 MWNTs@CeO 2 CNT@M/MO 2 J. Am. Chem. Soc., 134, 2012, 11760

48 2 on C-nanostructure : processability Zero Loss HRTEM EFTEM (Energy Filtered TEM)

49 2 on C-nanocones for photo-assisted H 2 production Cones and disk-like structures Homogenesously covered by Pd@TiO 2 TEM EDX mapping, HRTEM and FFT Perfect colocation of the phases (EDX) TiO 2 in anatase phase (FFT)

50 2 on C-nanocones for photo-assisted H 2 production 10 mg of catalyst in 1:1 v/v EtOH:H 2 O Light source (UV) = Hg lamp 125W Ox-CNC/Pd@TiO Largely more active Than C-free corresponding Pd@TiO catalyst Ar inlet Ar outlet Chem Commun, 2016, 52,

51 Synthesis of benzimidazole Conventional synthesis: NH 2 + O H N T = C Strong acidic conditions Strong oxidants NH 2 Very toxic and carcinogenic N

52 Synthesis of benzimidazole Alternative processes: Less toxic reagents Renewable and cheap solvent [H] ads hn, cat

53 Futher functionalization Synthesis of substituted benzimidazole Br Unpublished data

54 Perspectives Materials manipulation at nanoscale level and precise assembly of nano-building blocks in hierarchical catalysts can allow modulation of metal-support interactions leading to a step change in catalytic performances

55 Acknowledgements Dr. D. Barreca (Univ Padova and CNR - Italy) Prof. A. Abbotto (Bicocca- Italy) Prof. J.J. Delgado (Univ Cadiz - Spain) Prof. R.J. Gorte (UPenn - USA) Prof. C.B. Murray (UPenn - USA) Prof. M. Prato (Univ Trieste- Italy) Dr. M. Peruzzini (ICCOM CNR Firenze - Italy) Dr. F. Vizza (ICCOM CNR Firenze - Italy) Prof J. Vohs (UPenn - USA) Dr. E. Fonda (Soleil France) Prof. V. Matolin (Univ Prague Czech Rep) Financial support University of Trieste, FRA 2013 and 2015 Projects INSTM and Regione Lombardia - Atlante Project ICCOM-CNR, Qatar Science Foundation, COST CM1104, FP7 SACS Project