Julie N. Kadrmas and Julie C. Liu High Efficiency Low Cost

Electrochemical Ammonia Production

Julie N. Renner, Steve Szymanski, Proton OnSite Lauren Greenlee, NIST/University of Arkansas

Andrew Herring, Colorado School of Mines Douglas Tiffany, University of Minnesota

NH3 Fuel Conference

Chicago, IL September 22nd 2015

Outline

2

Proton OnSite Overview

Electrochemical Ammonia Synthesis

Results and Future Directions

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

H2O

H2O

O2

H2O

H2O

H2O

N2

H2O

H2O

H2O

NH3

NH3

AEM Catalyst

Layers

GDLs

OH-

e-

• Core technology in PEM electrolysis

• Founded in 1996, >2200 fielded units, 15 MW capacity shipped

• Continuing to scale manufacturing and output to address energy markets

• MW scale electrolyzer system now available

Proton OnSite Overview

Headquarters in Wallingford, CT

Electrolyzer Applications:

Power Plants Government

Heat Treating Laboratories

Semiconductors Proton Fueling Station

3

Renewable Energy Storage Biogas

Membrane-based Electrolysis

4

MembraneElectrode Assembly

Stack

• “PEM” electrode = Proton Exchange Membrane

• Reaction occurs across a thin MEA

• Assembled into compact stacks and systems

28 cm2

0.05 Nm3/hr 0.01 kg/day

86 cm2

2 Nm3/hr 4.3 kg/day

210 cm2

10 Nm3/hr 21.6 kg/day

680 cm2

50 Nm3/hr 100 kg/day

Up to three stacks per system

Scalable Technology

5

HOGEN® H Series

HOGEN® C Series

HOGEN® S Series HOGEN®

GC

From Single to Multi-Stack Systems

HOGEN® M Series

Product Type

S-Series H-Series C-Series Megawatt

Year Introduced 2000 2004 2012 2015

Units Sold 450+ 200+ 22+ NA

H2 output (Nm3/hr) 1 6 30 200–400

Generates 1 Day 1 Day 1 Week 1 Day

Replaces

Six Pack Tube Trailer Jumbo Tube Trailer Jumbo Tube Trailers

How Much Hydrogen Can We Make?

Input Power 6 kW 36 kW 180 kW 1 - 2 MW

$/kW vs. S-Series 100% 43% 28% 13%E

6

Outline

7

Proton OnSite Overview

Electrochemical Ammonia Synthesis

Results and Future Directions

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

H2O

H2O

O2

H2O

H2O

H2O

N2

H2O

H2O

H2O

NH3

NH3

AEM Catalyst

Layers

GDLs

OH-

e-

Ammonia Production History

8

0

1000

2000

3000

4000

5000

6000

7000

8000

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Est

imat

ed P

op

luat

ion

(m

illio

ns)

Year

mining

manufacturing

Fritz Haber Carl Bosch

mid 1800’s: mining

(1) History Today Volume 30 Issue 6 June 1980 (2) Dept. of the Interior US Geological Survey Bulletin 523, 1912

Guano mining1 Nitrate salt mining2

1899: Crooks raises alarm

1913: Haber-Bosch

• Haber-Bosch supports about half of the people on earth3

(3) J.W. Erisman, M.A. Sutton, J. Galloway, Z. Klimont, W. Winiwarter, Nat. Geosci., 1 (2008) 636-639.

Haber-Bosch (HB) Process

9

• H2 obtained from fossil fuels, high temp and high pressure, high capital cost

• Inefficient (consumes ~1% of the worlds energy)

• High-polluting (~3% GHG emissions) Ammonia Production: Moving Towards Maximum Efficiency and Lower GHG Emissions http://www.fertilizer.org/, 2014.

Feeding the Earth, International Fertilizer Industry Association, http://www.fertilizer.org/, 2009.

Vision for Electrochemical Ammonia Production

10

Ammonia Synthesis

Renewable

Power NH3

N2, water

Industrial Uses:

chemical synthesis,

emissions scrubbing,

refrigeration

Fertilizer

• Electrically driven process for low temp/pressure/emissions

• Compatible with intermittent operation

• High regional demand for fertilizer co-located with renewables

J.N. Renner, L.F. Greenlee, A.M. Herring, K.E. Ayers, Electrochemical Synthesis of Ammonia: A Low Pressure, Low Temperature Approach, in: The Electrochemical Society Interface, Summer 2015.

Wind to Ammonia Pilot Plant: University of Minnesota / Morris (West Central Research & Outreach Center)

Ammonia storage

Proton supplied H2 and N2 generation

Excess

RE

N2

Haber-Bosch reactor

NH3

Onsite wind power H2

H2 Toro fuel cell utility vehicle

Scalable Technology

12

• Enables networks of distributed scale and near point-of-use

• Proton developing MW-scale

A 5 MW system could produce 10 tons/day ammonia (@ 500 mA/cm2, 50% efficiency, 1.5 V)

HOGEN® H Series HOGEN® C Series

Up to three stacks per systemHOGEN®

S Series

HOGEN®

GC

From Single to Multi-Stack SystemsAmmonia Production Technology Plan

PHASE I

Bench Scale Size: 25 cm2

Proof-of-Concept PhaseBench Scale

TargetsCurrent Efficiency: > 1%

PHASE II

GC Size: 28-84 cm2

Breadboard PhaseGarden Capacity (100 g/year)

TargetsCurrent Efficiency: 10%Current Density: 10 mA/cm2

FUTURE

M Series: 250,000-500,000 cm2

Product PhaseSmall Farm (260 acres – 12,500 kg/year)

TargetsCurrent Efficiency: 50%Current Density: 50 mA/cm2

M Series

Background/Key Obstacles

13

• PEM demonstrated feasibility

• At 1.5 V and below, need ~50% Faradaic efficiency to match HB

• Key obstacle: selective catalyst • low NH3 overpotential

• high H2 overpotential

A volcano plot predicting metal performance for nitrogen electroreduction

Ap

plie

d P

ote

nti

al (

V)

Binding Energy

E. Skúlason, et. al, Phys. Chem. Chem. Phys., 14 (2012).

R. Lan, J.T.S. Irvine, S. Tao, Scientific Reports, 3 (2013).

Applied Potential (V)

Faradaic Efficien

cy (%)

NH

3 F

orm

atio

n R

ate

(X1

0-5

mo

l m-2

s-1

)

AEM-based Approach

14

• AEM enables wider range of efficient catalysts vs. PEM

• Lower cost materials of construction in alkaline environment

H2O

H2O

O2

Anode:

H2O

H2O

H2O

N2

H2O

H2O

H2O

NH3

NH3

12 OH- 3 O2 + 6 H2O + 12 e-

Cathode:

12 H2O + 2 N2 + 12 e- 4 NH3 + 12 OH-

AEM Catalyst

Layers

GDLs

OH-

e-

More Catalyst Options:

• Non-noble

• Blended metals

• Core-shell

• Ligands

Outline

15

Proton OnSite Overview

Electrochemical Ammonia Synthesis

Results and Future Directions

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt0.00.51.01.52.02.53.03.54.04.55.0

Hour 1 Hour 2 Hour 3 Hour 4(after water

rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

Fe-Pt

H2O

H2O

O2

H2O

H2O

H2O

N2

H2O

H2O

H2O

NH3

NH3

AEM Catalyst

Layers

GDLs

OH-

e-

Ammonia Generation Rig

16

• Design reviewed by senior engineers, safety qualified

• Test bed to compare multiple configurations and catalysts

• Sensitive colorimetric assay for ammonia (verified independently)

Increasing ammonia concentration

Ammonia Capture via Acid Trap and Determination via Colorimetric Assay:

Membrane Screening

17

• 9X greater diffusion through higher IEC material

• May indicate hydrophobicity/swelling in limiting ammonia crossover

• Good performing membranes have an order of magnitude less crossover than baseline production rates

• Commercial baseline material good starting point

AEM

NH3

DI Water

0.00000

0.00005

0.00010

0.00015

0.00020

0.00025

0.00030

Lower IEC Higher IEC Commercial Baseline

No

rmal

ized

Am

mo

niu

m

Cro

sso

ver

(mg*

mil/

min

*cm

2)

Commercial Catalyst Screening

18

• Platinum consistently had <1% efficiencies (similar to PEM), performance degrades after an hour

• Order of magnitude increase in efficiencies with non-noble metal

• Increased efficiency seems to correlate with decreased production

• Indicates competition between HER and NH3 production

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0

5E-13

1E-12

1.5E-12

2E-12

2.5E-12

3E-12

3.5E-12

4E-12

4.5E-12

5E-12

Pt Fe Ni Mn

Cathode Catalyst

Pro

du

ctio

n R

ate

(m

ol N

H3 /

s cm

2 )

Cu

rrent Efficien

cy (%)

Conditions: 1.3 V, 0.5 hours of operation

Effect of Voltage

19

• Increasing production rate and efficiency with increasing potential using Fe (opposite effect with Ni)

• High current efficiencies possible with Ni

• Provides further evidence for competition between HER and NH3 production

0.00E+00

5.00E-13

1.00E-12

1.50E-12

2.00E-12

2.50E-12

0.0

0.5

1.0

1.5

2.0

1 1.2 1.4 1.6

Potential (V)

Pro

du

ction

Rate (m

ol N

H3 /s cm

2 )

Cu

rren

t Ef

fici

ency

(%

)

Conditions: 1 hour of operation at each voltage step

0.00E+00

2.00E-13

4.00E-13

6.00E-13

8.00E-13

1.00E-12

1.20E-12

0.0

2.0

4.0

6.0

8.0

10.0

12.0

1 1.2 1.4 1.6

Potential (V)

Cu

rren

t Ef

fici

ency

(%

)

Pro

du

ction

Rate (m

ol N

H3 /s cm

2 )

Commercial Fe Commercial Ni

Catalyst Synthesis

20

FeNi Low SA

FeNi High SA

Large Fe-only Small Ni-only

• Exquisite control over nanoparticle morphologies for Ni and Fe compounds

• Compared to commercial Pt

Nanoparticle performance

21

• Performance of Ni-Fe materials are affected by surface area

• LSA more Fe like

• HAS more Ni like

• Ni materials have higher stability and efficiency

• Pt performance degrades

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Hour 1 Hour 2 Hour 3 Hour 4(after water rinse)

Effi

cie

ncy

, % (

1.2

V)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

0.00E+00

1.00E-12

2.00E-12

3.00E-12

4.00E-12

5.00E-12

6.00E-12

7.00E-12

8.00E-12

9.00E-12

Hour 1 Hour 2 Hour 3 Hour 4(after water rinse)

Am

mo

nia

Pro

du

ctio

n R

ate

(m

ol c

m-2

s-1

)

Pt black

Fe-Ni LSA (1)

Fe-Ni LSA (2)

Fe-Ni HSA

Ni only

Fe only

* Fe-only efficiency at hour 1 is non-zero, estimated >10%

Conditions: 1.2 V, 1 hour of operation

Pro

du

ctio

n R

ate

(m

ol N

H3 /

s cm

2 )

Effi

cien

cy (

%)

Hour 1 Hour 1 Hour 2 Hour 3 Hour 2 Hour 3

Comparison

22

• Orders of magnitude increase in current efficiency compared to PEM

• Similar efficiencies at lower temperatures than molten hydroxide

• Production rates need to be increased

Process Catalyst

Energy

Consumption

(kwh/kg NH3)

Ammonia

Production Rate

(mol NH3/cm2s)

Faradaic

Efficiency

(%)

Cell

Potential

(V)

Temp

(°C)

Haber-Bosch1 Typically

Fe-based 13.2 N/A N/A N/A

300-

500

PEM

Electrochemical2 Pt 1600-3600

6.20 X 10-10 –

2.80 X 10-10 0.16-0.36 1.2-1.4 25

Mixed Electrolyte

Electrochemical3

perovskite

oxide 130 - 1140

3.1 X 10-11 –

1.71 X 10-10 0.5-4.5 1.2-1.4 400

Molten Hydroxide

Electrochemical4 Fe2O3 16 2.40 X 10-9 35 1.2 200

AEM

Electrochemical

Pt, Fe, Ni,

FeNi 14-520

1.33 X 10-12 –

3.80 X 10-12 1.1 - 41 1.2 50

(1) W. Leighty, The Leighty Foundation, Energy Storage with Anhydrous Ammonia: Comparison with other Energy Storage, October 2008.

(2) R. Lan, J.T.S. Irvine, S. Tao, Scientific Reports, 3 (2013)

(3) R. Lan, S.W. Tao, RSC Adv., 3 (2013) 18016-18021.

(4) S. Licht, B.C. Cui, B.H. Wang, F.F. Li, J. Lau, S.Z. Liu, Science, 345 (2014) 637-640.

Conclusions

23

• The developed system provided an adequate test bed

• Proof-of-concept was established for AEM-based ammonia generation

• An order of magnitude increase in efficiency was observed compared literature at similar conditions

H2O

H2O

O2

H2O

H2O

H2O

N2

H2O

H2O

H2O

NH3

NH3

AEM Catalyst

Layers

GDLs

OH-

e-

• AEM-based technology is promising for efficient ammonia production at low temperatures

How do we achieve our vision?

24

Ammonia Synthesis

Renewable

Power NH3

N2, water

Industrial Uses:

chemical synthesis,

emissions scrubbing,

refrigeration

Fertilizer

Phase II Work:

• New ammonia rig

• More detailed product analysis

• NiFe and other nanocatalysts

• Membrane/ionomer/electrode optimization

• Demonstrate increased current density and durability

• Technoeconomic analysis

Future Work:

• Fundamental studies on reaction mechanisms

• Bio-inspired catalysts for selectivity

• Purification and systems work

• Scale-up

Acknowledgements Proton OnSite:

• Kathy Ayers

• Nemanja Danilovic

• Luke Wiles (engineering asst.)

• Arie Havasov (co-op)

• Wolfgang Grassmann (co-op)

Collaborators:

• Lauren Greenlee NIST/Univ. of Arkansas

• Andrew Herring Colorado School of Mines

• Douglas Tiffany University of Minnesota

Questions and Discussion

Funding: •USDA Phase I/II SBIR

•NSF/ASEE Postdoctoral Fellowship