J_K_Norskov

8/12/2019 J_K_Norskov

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Catalytic hydrogen production

J. K. Nrskov

Center for Atomic-scale Materials Physics

Technical University of Denmark

[email protected]


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Hydrogen production strategies

Reforming of hydrocarbons Reforming of biomass

Electrolysis Photolytic conversion

Biological conversion ..


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Steam reforming

CH4+H2O 3H2+CO

DH= +206 kJ/mol

Ni catalyst

Rostrup-Nielsen, Sehested, Nrskov

Adv. Catal. 47, 65 (2002)


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The atomic-scale picture

Ni(111)

Ni(211)

Bengaard, Nrskov, Sehested, Clausen, Nielsen, Molenbroek, Rostrup-Nielsen: J. Catal. 209, 365 (2002)


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Problems

1. Carbon formation

2. Metal dusting

3. Too much CO


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Formation of Carbon

Nano-fibersIn situ (high

temperature

and pressure)

Transmission

Electron

Microscopy (TEM)

The movies:

http://www.haldortopsoe.com/site.nsf/all/EOTT-5VTMPT?OpenDocument

Helveg, Cartes, Sehested, Hansen, Clausen, Rostrup-Nielsen, Abild-Pedersen, Nrskov

Nature 327, 426 (2004)
http://www.haldortopsoe.com/site.nsf/all/EOTT-5VTMPT?OpenDocumenthttp://www.haldortopsoe.com/site.nsf/all/EOTT-5VTMPT?OpenDocumenthttp://www.haldortopsoe.com/site.nsf/all/EOTT-5VTMPT?OpenDocument


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The role of steps

Helveg, Cartes, Sehested, Hansen, Clausen, Rostrup-Nielsen, Abild-Pedersen, Nrskov

Nature 327, 426 (2004)


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Carbon nucleation at steps

Ni(211)

Bengaard, Nrskov, Sehested, Clausen, Nielsen, Molenbroek, Rostrup-Nielsen: J. Catal. 209, 365 (2002)

Extra bonding at step

Ni(111)


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Step blocking

MD simulation Au/Ni

Molenbroek, Nrskov, Clausen

J. Phys. Chem. B 105, 5450 (2001)


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Catalyst design at the nano-scale

Besenbacher, Chorkendorff, Clausen, Hammer, Molenbroek, Nrskov, Stensgaard,

Science 279, 1913 (1998)


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Too much CO

S. Gottesfeld et al., J. Electrochem. Soc. 148 (2001) A11.

CO poisons PEM fuel cell:CO is a product:

CH4+H2O 3H2+CO

Possible solutions:

Make fuel cell less

CO poisoned

Remove CO


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CO blocks for hydrogen adsorption at the anode

H coverage in the presence of CO:

T=80 oC

ECO=-1.4 eV

EH2=-0.5 eV

H

x104

ppm CO in 1 bar H2

Christoffersen, Liu, Ruban, Skriver, Nrskov: J.Catal. 199, 123 (2001)


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New 3-component alloys from DFT

Ru

PtM PtRu

Pure Fe Co Rh Ir Ni Pd Pt Cu Ag Au Sn

0,00

0,03

0,06

0,09

0,12

0,15

0,18

DECO-1

/2DEH2

(eV)

PtRuNi

PtRuCo

Measure of competition

Between CO and H:

DECO-1/2 DEH2

Pt M

Strasser, Fan, Devenney, Weinberg, Liu , Nrskov, J. Phys. Chem.B, 107, 11013 (2003)


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Combinatorial Electrochemistry

Electrochemical Multi-electrode array64 addressable electrodes

PhotolitographicFabrication

Symyx Technologies

proprietaryUS Patent No 6,187,164; 5,985,356; 6,004,617.

Additional US and foreign patents pending


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Results from parallel screening experimentsStrasser, Fan, Devenney, Weinberg

Symyx Technologies

Relative

area-norm

alizedactiv

ity

Lo

g[(I

alloy

/Aalloy,real

)/(IPt/

APt,real)

]

0.00

0.40

0.80

1.20

1.60

Pt

Pt60Ru40

Pt60Co20Ru20

Pt40Co40Ru20

Pt20Co60Ru20

Pt60Ni20Ru20

Pt40Ni40Ru20Pt20Ni60Ru20

Strasser, Fan, Devenney, Weinberg, Liu, NrskovJ. Phys. Chem.B 107, 11013 (2003)

W t hift Th h i t


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-5

-4

-3

-2

-1

0

1

2

3

CO(g)+2H2O(g)

CO(a)+2H2O(g)

CO(a)+2H2O(a)CO2(a)+2H(a)

+H2O(a)

CO2(a)+H2(g)

+H2O(a)

CO2(g)+H2(g)+

H2O(g)

Au

Ag

Cu

Pd

Pt

CoNi

Ru

Rh

Ir

CO(a)+ 2H(a)

+O(a) +H2O(a)

Disproportionation :

OH* + OH* H2O* + O*

CO(a)+H(a)

+OH(a)+ H2O(a)

Complete Dissociation :

OH* +* O* + H*

CO(a)+2H(a)

+2OH(a)

E

nergy(eV)

Water gas shift: Thermochemistry

Courtesy of M. Mavrikakis UW Madison


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Nano effects in catalysis

CO oxidation on Au particles supported on TiO2

Valden, Lai, Goodman,

Science 281, 1647 (1998)

Wahlstrm, Lopez, Schaub, Thostrup,

Rnnau, Africh, Lgsgaard, Nrskov,

Besenbacher, PRL 90, 026101 (2003)

No generally accepted explanation yet!


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Reforming of biomass

Huber, Shabaker, Dumesic, Science 300, 20752077 (2003).

Reforming of oxygenated hydrocarbons over Raney-NiSn.


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Electrolysis

Cathode: 2(H++e-) H2

Anode: H2O O2 +2 H+

____________________________________

Total: H2O O2 +H2

DG0 =2.46 eV (1.23 eV/electron)


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The overpotential

Ni-based electrolyzer:U = U0 + hcathode + hanode+ I R

Efficiency:

%65~~ 9.123.1)(0 VViUU

Wendt, Imarisio, J. Appl. Electrochem. 17, 1 (1988)


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Photovoltaics+electrolyzer

12% x 65% = 7.8%


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The origin of the overpotential

Kitchin, Bligaard, Stimming, NrskovEven larger barriers at the anode!


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A Pt/Pt cell

Khaselev, Bansal, Turner, Int. J. Hydrogen Energy 26, 127 (2001)

i i i h d d i


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Biomimetic hydrogen production

The active site

Gloaguen, Lawrence, Rauchfuss, JACS 123, 9476 (2001)

Siegbahn, Blomberg, Wirstam, CrabtreeJ. Biological Inorganic Chemistry. 6, 460 (2001)

Hydrogenase catalyses

H++e- H2

Add active site to electrode?

Or make structure with

similar properties?

Lamle, Vincent, Halliwell, Albracht,

Armstrong, Dalton Trans. 2003 4152

Bi i i h d d i II


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Biomimetic hydrogen production II

Nitrogenase:

Hinnemann, Nrskov, JACS 126, 3920 (2004)

Th d h ll


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The grand challenge

Understand relationship between

surface structure and catalytic properties

Use insight for rational

(atomic-scale)

design of new catalysts

Theory

Model experiments

Synthesis of new nano particle catalysts

Testing and characterization

Th k t


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Thanks to

B. Hinnemann, K. Honkala, T. Bligaard, H. Beengaard, F. Abild-Pedersen,P. Liu, A. Logadottir, I. Chorkendorff

Center for Atomic scale Materials Physics, Technical University of Denmark

F. Besenbacher, E. Vestergaard, R. Vang

Center for Atomic scale Materials Physics, University of Aarhus

S. Helveg, B. S. Clausen, J. Rostrup-Nielsen, J. Sehested, A. Molenbroek

Haldor Topse

J. R. Kitchin, M. A. Barteau, J. G. Chen

University of Delaware

P. Strasser, H. Weinberg

Symyx

U. Stimming

Technical University Munich

M. Mavrikakis

University of Wisconsin, Madison

J_K_Norskov

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