Design Principles for Catalyzing CO2 Electro-Reduction to Fuels and Chemicals

on Transition Metal Surfaces Thomas F. Jaramillo,1 Jens K. Nørskov,1,2 Anders Nilsson2

1Dept. of Chemical Engineering, Stanford University 1SLAC National Accelerator Laboratory, Menlo Park, CA

October 14, 2014

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Global Climate Energy Project (GCEP) Stanford University

Stanford, CA

Central theme: Catalyst design principles

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Fundamental studies to identify design principles

(1) Identify the key design principles for improved catalysis. (2) Engineer those principles into new catalyst materials.

Background on CO2 electro-reduction

High overpotential (~1 V)

3 • Hori, Y. (2003). CO2-reduction, catalyzed by metal electrodes. Handbook of Fuel Cells: Fundamentals, Technology and Application. A. L. Wolf Vielstich, Hubert A. Gasteiger. Chichester, VHC-Wiley. 2: 720-733.

Thermodynamic & Kinetic Considerations

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E0 vs. RHE

0.00 V - 0.11 V + 0.16 V + 0.07 V + 0.08 V + 0.09 V

All values are close to the H2 evolution potential (0.00 V).

+H+ +e- +H+ +e- +H+ +e- +H+ +e- +H+ +e- +H+ +e- +H+ +e- +H+ +e-

2H+ + 2e- H2 CO2 + 2H+ + 2e- CO + H2O CO2 + 8H+ + 8e- CH4 + 2H2O 2CO2 + 12H+ + 12e- C2H4 + 4H2O 2CO2 + 12H+ + 12e- C2H5OH + 3H2O 3CO2 + 18H+ + 18e- C3H7OH + 5H2O

A. Peterson, F. Abild-Pederson, F. Studt, J. Rossmeisl, J.K. Nørskov, Energy& Environmental Science v3 (2010) 1311-1315.

Y. Hori, “Electrochemical CO2 reduction on metal electrodes” within Modern Aspects of Electrochemistry, Number 42, Edited by C. Vayenas et. al., Springer, New York, 2008.

Continuous flow electrochemical reactor • Custom electrolysis cell @ STP

– 5.9 cm2 electrode area – 9 mL electrolyte

• Potentiostatic 1 hr electrolysis • 0.1 M KHCO3 electrolyte, pH 6.8 • Constant CO2 purge • IR compensated • Product identification/quantification

– Gases: gas chromatography (GC) – Liquid: nuclear magnetic resonance (NMR)

• 1H NMR • 13C NMR

• Seven transition metals studied: – Cu, Au, Ag, Zn, Ni, Pt, Fe

5 K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

Observed CO2 reduction products on Cu

Global ‘Top 50’ ~ billions of kg/yr production

Current Density • CO and formate pull near

constant current across voltage range.

• H2 is mostly constant, then increases at high V.

• CH4 production rate constantly increasing with Tafel behavior.

• C2 and C3 products clearly rise and fall together.

K.P. Kuhl, E. Cave, D.N. Abram, & T.F. Jaramillo, Energy & Environmental Science, Vol. 5, pp. 7050-7059, 2012.

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Proposed Pathway

Enol-like surface species responsible for C2 and C3 chemistry

8 K.P. Kuhl, E. Cave, D.N. Abram, & T.F. Jaramillo, Energy & Environmental Science, Vol. 5, pp. 7050-7059, 2012.

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What about other transition metals?

Seven different transition metals

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Total current density (H2 + CO2 reduction products)

% of current going to CO2 reduction products

From CatApp: CO Binding Energy (eV)

K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

A CO2RR volcano

11 K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

Measurements on CO2RR selectivity

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Metal H2 CO HCOO- CH4 CH3OH C2’s Au Ag

Zn

Cu Pt Ni Fe

• Major products match literature reports • Hydrocarbon and/or alcohol production detected on all metals

– Copper is not quite as special as we once thought….

+

Major Products

Minor Products

Novel Products

Hori, Y. (2003). CO2-reduction, catalyzed by metal electrodes. Handbook of Fuel Cells: Fundamentals Technology and Application. A. L. Wolf Vielstich, Hubert A. Gasteiger. Chichester, VHC-Wiley. 2: 720-733.

Methane vs. Methanol

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• Turnover frequencies for methane and methanol correlate with one another.

• Could suggest similarities in the r.d.s. for both • e.g. CO + H+ + e- CHO or COH

• Could suggest common intermediates

for CH4 & CH3OH. • Pathways possibly differentiated

midway through the reaction by breaking the 2nd C-O bond.

CO2 Common Intermediates

CH4

MeOH K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

A 2nd CO2RR volcano using onset potentials

14 K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

A 2nd CO2RR volcano using onset potentials

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Limited by CO desorption.

Limited by CO hydrogenation to CHO or COH.

K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

Design principle: Need to break scaling relations

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A. Peterson, J.K. Nørskov, Journal of Physical Chemistry Letters v3 (2012) 251-258.

K. Kuhl, T. Hatsukade, E.R. Cave, D.N. Abram, J. Kibsgaard, T.F. Jaramillo, J. Am. Chem. Soc. , v136, pp. 14107-14113, 2014.

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How can one engineer improved activity?

• Alloying • Controlling surface structure • Overlayers

Reactivity volcano: CO2 to CO

• No problem, in principle, to find better catalyst

• Scaling between E(COOH) and E(CO) limits rate

• Design strategies must include methods for stabilizing *COOH vs *CO

Hansen, Varley, Peterson, Nørskov JPC Lett. 4, 388 (2013) 18

J (mA/cm2)

Applied potential (V)

Armstrong and co-workers, JACS 2007, PNAS 2011

Experimentally proposed active site in CODH II [Ni-4Fe-5S]

Ch-CODH I immobilized on electrodes

Enzymes work better ….

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How does an enzyme “beat scaling”?

20 Hansen, Varley, Peterson, Nørskov JPC Lett. 4, 388 (2013)

Alloying

21 H. Hansen, J.K. Nørskov, et. al. (2014).

Pt-In Alloys

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CO HCOO- H2

Alloying has a profound effect on selectivity.

C.J. Hahn, D.N. Abram, T.F. Jaramillo, et. al. (2014).

PtInx (2 ≤ x ≤ 19) Pt In

Pt produces H2 as the major product.

In produces HCOO- as the major product.

Pt-In alloys produce CO as the major product!

Electrochemical Mass Spectrometry

• real-time product detection • allows for studies on single crystals

Teflon frit

To mass spec

23 K.P. Kuhl, F.S. Roberts, A. Nilsson, et. al. (2014).

Single crystal surface images from: Norskov et al. Surf. Sci. 605, 1354-59

Best of the three at producing ethylene.

200 nm

Cube structure offers: • high surface area • (100) facets and steps

Cu nano-cubes produce 170 X more ethylene than methane!

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Copper nano-cubes: enhanced ethylene production

K.P. Kuhl, F.S. Roberts, A. Nilsson, et. al. (2014).

Au nanoparticle overlayers on Cu

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Polycrystalline Cu foil PVD 8 Å of Au on Cu

E.R. Cave, T.F. Jaramillo, et. al. (2014).

Cu vs. AuCu

26 E.R. Cave, T.F. Jaramillo, et. al. (2014).

Summary

• Catalyzing CO2 reduction – New tools and

methodologies have provided new insights.

– Transition metal surface chemistry is more rich than previously thought.

– Theory is crucial to understanding this complex chemistry.

– New insights are leading to directed approaches to catalyst development.

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By identifying design principles for catalysis, one can accelerate the development of improved materials.

Acknowledgments PhD students • Zhebo Chen (PhD 2012) • Yelena Gorlin (PhD 2012) • Ben Reinecke (PhD 2013) • Kendra P. Kuhl (PhD 2013) • Blaise Pinaud (PhD 2013) • Etosha Cave • David Abram • Jesse Benck • Desmond Ng • Linsey Seitz • Ariel Jackson

Post-doctroral Researchers • Dr. Jakob Kibsgaard • Dr. Annelie Jongerius • Dr. Sam Fleischman • Dr. Chris Hahn

Undergraduate Researchers • Kara Fong • Sigberto Alarcón Viesca • Robert Kravec

• Toru Hatsukade • Pong Chakthranont • Ieva Narkeviciute • Jeremy Feaster • Tommy Hellstern • Jon Snider • Alaina Strickler • Reuben Britto

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Three approaches in GCEP to CO2 catalyst development

• Matthew Kanan: Nano-structured electrode materials

• Robert Waymouth: A molecular approach

• Thomas Jaramillo: Catalyst design principles, theory and experiment

oxide-derived Cu

oxidation reduction

Cu2O/Cu electrode

100 nm