past, present, and future challenges in electrocatalysis for fuel

1 | Fuel Cell Technologies Office eere.energy.gov

FCTO Monthly Webinar Series:

Past, Present and Future Challenges in Electrocatalysis for Fuel Cells

U.S. Department of Energy Fuel Cell Technologies Office October 13th, 2016

Presenter: Voya (Vojislav) Stamenkovic Argonne National Laboratory

DOE Host: Dimitrios Papageorgopoulos Fuel Cell Technologies Office

2 | Fuel Cell Technologies Office eere.energy.gov

Question and Answer

• Please type your questions into the question box

2

M a t e r i a l s S c i e n c e D i v i s i o n A r g o n n e N a t i o n a l Laboratory

DOE EERE Fuel Cell Technology Office Webinar Series October 13, 2016

Past, Present and Future Challenges in Electrocatalysis for Fuel Cells

Vojislav Stamenkovic

https://www.toyota.com/mirai/fcv

2016 Toyota Mirai $499/month 36-month lease $57,500 MSRP

HYDROGEN SAFETY Science behind the safety Safety was our primary objective when we engineered the Mirai. Our proprietary safety system is based on four fundamental principles.

The first production fuel cell vehicle The Mirai is at the forefront of a new age of hydrogen fuel cell cars that allows you to enjoy long distance zero-emissions driving. As well as only producing water from its tailpipe – which means no impact on our planet when you're driving – Mirai brings the unique Toyota Hybrid driving experience to a new level.

’60s

’60-70s

’80-2011

PEM FC unsupported Pt catalyst loading: 28 mgPt/cm2 membrane: Nafion T ~ 21oC

Alkaline FC Ni based catalyst T ~ 250oC Operating time: 400-690h

Alkaline FC Pt and PtAu catalysts loading: 10 and 20 mgPt/cm2 T ~ 93oC Operating time: > 16 days

cubo-octahedral particles

30 nm (Pt/C) 10 % Pt/Vulcan 3 nm

Particle Size Effect

5

ORR: cathode limitations

Main limitations in PEM fuel cell technology:

2) Durability: (Pt catalyst dissolves) 3) Pt loading: Cost Issues

1) Activity: Pt/C = Pt-poly/10

losses ~ 30-40% (!!!) Cathode kinetics (?!)

2020 DOE Technical Targets

• Durability w/cycling (80oC): 5000 hrs

• Mass activity @0.9V: 0.44 A/mgPt

• PGM Total content: 0.125 g/kW

• Electrochemical area loss: < 40%

• PGM Total loading: 0.125 mg/cm2 electrode

7

Activity | Durability | Cost

3o Surface Modifications

1o Structure-Function

4o Tailored Electrolytes

Specific/Mass Activity Electrochemical Stability Loading

2o Composition-Function

(c)As prepared

As prepared

(a) (b)

Curr

ent D

ensi

ty (a

. u.)

STM: Pt Single Crystals

Pt(111) Pt(100)

Pt(110)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0.925 V 0.900 V 0.875 V 0.850 V

Kin

etic

Cur

rent

Den

sity

[mA

/cm

^2]

Pt(110)Pt(111)Pt(100)Series4Pt-poly average

9

Dissolved Pt per cycle [µML]

Pt Surface

Total Pt loss over one potential cycle up to 1.05 V for distinct Pt surface morphologies, indicating the stability trend follows the coordination number of the surface sites

Pt(111) 2

Pt(100) 7

Pt(110) 83

Pt-poly 36

Pt/C | 103*

Quadrupole mass filter

Horizontal torch

Electrochemical Cell

P. P. Lopes, D. Strmcnik, J. Connell, V. R. Stamenkovic and N.M. Markovic ACS Catalysis, 6 (4), 2536-2544, 2016

In-Situ EC-ICP-MS Pt(hkl)-Surfaces vs. Pt/C

10

[011]

[01-1]

(110)-(1x1)

p(1x1)

Pt3Ni(110)

(e) Pt3Ni(100)

c(5x1)

(f)

Pt3Ni(111)(d)

[1-1

0]

[001]

LEED

Surface Structure + Composition: Pt3Ni[hkl] Surfaces

Sputtered

Annealed

STM

LEIS

11

Activity: ORR Platinum Alloy Surfaces

Pt3Ni(110) Pt3Ni(100)

Pt(hkl)

Pt3Ni(111)

Pt3Ni(hkl)

0.1 M HClO4

Pt3Ni(hkl)

(110) (111) (100)

Pt (111)

0.1 M HClO4 0.95 V vs. RHE 20 °C

Pt3Ni(hkl)

Pt3Ni(111)/Pt-Skin Surface is the most active catalyst for the ORR

Science, 315 (2007) 493 12

60

E [V] vs. RHE0.0 0.2 0.4 0.6 0.8 1.0

Inte

nsit

y [a

rb. u

nits

]

6.0

6.5

7.0

1 2 3 4 5 6 7

Pt [a

t. %

]

0

20

40

60

80

100

100

80

60

20

0

40

Pt [

at. %

]

Ni [

at. %

]

Atomic layer

SXS

(b)

(a)

(a’)

Θ

Hup

d [%

]

60

30

0

60

30

0

ΘO

xd [

%]

i [µ

A/c

m2 ]

60

30

0

-60

-30

Pt3Ni(111)

Pt(111)

y

CV

(c)

E [V] vs. RHE0.0 0.2 0.4 0.6 0.8 1.0

i [m

A/c

m2 ]

-6

-4

-2

0

I II III

H2O

2 [%

]

Pt poly

050

ORR

(d)

∆E~100 mV

Subsurface Composition + Surface Structure: Pt3Ni(111)

Science, 315(2007)493

Pt3Ni(111)/Pt-Skin Surface is the most active catalyst for the ORR (100-fold enhancement)

13

60

E [V] vs. RHE0.0 0.2 0.4 0.6 0.8 1.0

Inte

nsit

y [a

rb. u

nits

]

6.0

6.5

7.0

1 2 3 4 5 6 7

Pt [a

t. %

]

0

20

40

60

80

100

100

80

60

20

0

40

Pt [

at. %

]

Ni [

at. %

]

Atomic layer

SXS

(b)

(a)

(a’)

Θ

Hup

d [%

]

60

30

0

60

30

0

ΘO

xd [

%]

i [µ

A/c

m2 ]

60

30

0

-60

-30

Pt3Ni(111)

Pt(111)

y

CV

(c)

E [V] vs. RHE0.0 0.2 0.4 0.6 0.8 1.0

i [m

A/c

m2 ]

-6

-4

-2

0

I II III

H2O

2 [%

]

Pt poly

050

ORR

(d)

∆E~100 mV

Subsurface Composition + Surface Structure: Pt3Ni(111)

Science, 315(2007)493

Pt3Ni(111)/Pt-Skin Surface is the most active catalyst for the ORR (100-fold enhancement)

13

Controlled Synthesis: Multimetallic Nanocatalysts

Colloidal solvo - thermal approach has been developed for monodispersed PtM NPs with controlled size and composition

Efficient surfactant removal method does not change the catalyst properties

Controlled Synthesis: Multimetallic Nanocatalysts

Colloidal solvo - thermal approach has been developed for monodispersed PtM NPs with controlled size and composition

Efficient surfactant removal method does not change the catalyst properties

4o Surface chemistry of homogeneous Pt-bimetallic NPs PtxM(1-x) NPs

Dissolution of non Pt atoms forms Pt-skeleton surface

3o Composition effect in Pt-bimetallic NPs Pt3M

Optimal composition of Pt-bimetallic NPs is PtM 1 nm

0.22 nm

1 nm1 nm

PtM PtM2 PtM3

1o Particle size effect applies to Pt-bimetallic NPs Specific Activity increases with particle size: 3 < 4.5 < 6 < 9nm

Mass Activity decreases with particle size

Optimal size particle size ~5nm J. Phys. Chem. C., 113(2009)19365

2o Temperature induced segregation in Pt-bimetallic NPs Agglomeration prevented

Optimized annealing temperature 400-500oC

(b)

Phys.Chem.Chem.Phys., 12(2010)6933

Adv. Funct. Mat., 21(2011)147

HAADF - STEM

1 2 3 4 5 6 7 8 9 100

20

40

60

80

100davg = 5.9 nm

Coun

tsSize (nm)

Particle size distribution

PtM Alloy NPs | Distribution: Elements and Particle Size

ACS Catalysis, 1 (2011) 1355 14

Controlled Synthesis: Multimetallic Nanocatalysts

Colloidal solvo - thermal approach has been developed for monodispersed PtM NPs with controlled size and composition

Efficient surfactant removal method does not change the catalyst properties

4o Surface chemistry of homogeneous Pt-bimetallic NPs PtxM(1-x) NPs

Dissolution of non Pt atoms forms Pt-skeleton surface

3o Composition effect in Pt-bimetallic NPs Pt3M

Optimal composition of Pt-bimetallic NPs is PtM 1 nm

0.22 nm

1 nm1 nm

PtM PtM2 PtM3

1o Particle size effect applies to Pt-bimetallic NPs Specific Activity increases with particle size: 3 < 4.5 < 6 < 9nm

Mass Activity decreases with particle size

Optimal size particle size ~5nm J. Phys. Chem. C., 113(2009)19365

2o Temperature induced segregation in Pt-bimetallic NPs Agglomeration prevented

Optimized annealing temperature 400-500oC

(b)

Phys.Chem.Chem.Phys., 12(2010)6933

Adv. Funct. Mat., 21(2011)147

PtxNi1-x: Surface Chemistry and Composition Effect

15 Adv. Funct. Mat., 21 (2011) 14715

PtxNi1-x: Surface Chemistry and Composition Effect

15 Adv. Funct. Mat., 21 (2011) 14715

As-prepared PtNi

Inte

nsity

(a. u

.)

Position (nm)43 5210

Position (nm)43 5210

Inte

nsity

(a. u

.)

Pt Ni

400oC

Temperature annealing protocol used to transform PtNi1-x skeletons to multilayered PtNi/Pt NPs with 2-3 atomic layers thick Pt-Skin

PtNi1-y Skeleton

HRTEM

Line profile

PtNi/Pt core/shell

PtNi with multilayered Pt-Skin Surfaces : Tailoring Nanoscale Surfaces

16

Catalysts with multilayered Pt-skin surfaces exhibit substantially lower coverage by Hupd vs. Pt/C

(up to 40% lower Hupd region is obtained on Pt-Skin catalyst)

Electrooxidation of adsorbed CO (CO stripping) has to be performed for Pt-alloy catalysts in order to avoid underestimation electrochemically active surface area and overestimation of specific and mass activities

Surface coverage of adsorbed CO is not affected on Pt-skin surfaces

As Synthesized Leached Annealed

∆

Multilayered Pt-skin NP

Ratio between QCO/QHupd>1 is indication of Pt-skin formation

TEM

Pt-NPs PtNi-NPs

davg = 5 nm

Catalyst QH (µC)

ECSAH (cm2)

QCO (µC)

ECSACO (cm2)

QCO/2QH

Pt/C 279 1.47 545 1.41 0.98 PtNi/C 292 1.54 615 1.60 1.05

PtNi-skin/C 210 1.10 595 1.54 1.42

NPs with multilayered Pt-Skin Surface: PtNi/C

17

-0.1

0.0

0.1

0.0 0.2 0.4 0.6 0.8 1.0

6 nm Pt/C acid treated PtNi/C acid treated/annealed PtNi/C

E (V vs. RHE)

i (m

A/cm

2 Pt)

0.6 0.7 0.8 0.9 1.0

-6

-4

-2

0

E (V vs. RHE)

i (m

A/cm

2 geo)

0.1 10.90

0.95

1.00

E (V

vs.

RHE

)jk (mA/cm2)

8320 8340 8360 8380 8400

0.0

0.5

1.0

1.5

acid treated acid treated/annealed Ni NiO

Norm

aliz

ed A

bsor

ptio

n µ(

E)

E (eV)

Ni K at 1.0 V

11540 11560 11580 11600 11620

0.0

0.5

1.0

1.5

acid treated acid treated/annealed Pt

Norm

aliz

ed A

bsor

ptio

n µ(

E)

E (eV)

Pt L3 at 1.0 V

a

b

c

ed

RDE: PtNi-Skin catalyst exhibits superior catalytic performance for the ORR and is highly durable system

TEM/XRD: Content of Ni is maximized and allows formation of the multilayered Pt-skin by leaching/annealing

In-Situ XANES: Subsurface Ni is well protected by less oxophilic multilayered Pt-skin during potential cycling

PtNi Catalyst: RDE Studies of Multilayered Pt-Skin Surfaces

0.0

0.2

0.4

0.6

0.8

1.0 before

Spec

ific

Act

ivity

(mA

/cm

2 )

after

0

2

4

6

Impr

ovem

ent F

acto

r(v

s. P

t/C)

0

2

4

6

8

10

after before

Durability: Surface area loss about 10%, SA 8 fold increase and MA 10 fold increase over Pt/C after 20K cycles

PtNi/C Pt/C PtNi/C Skin

18

Skeleton

J. Amer. Chem. Soc. 133 (2011) 14396

- H2PtCl6 and Ni(NO3)2 react in oleylamine at 270oC for 3 min forming solid PtNi3 polyhedral NPs

- Reacting solution is exposed to O2 that induces spontaneous corrosion of Ni - Ni rich NPs are converted into Pt3Ni nanoframes with Pt-skeleton type of surfaces

- Controlled annealing induces Pt-Skin formation on nanoframe surfaces

Science , 343 (2014) 1339

Mass Activity Enhancement by 3D Surfaces: Multimetallic Nanoframes

In collaboration with Peidong Yang, UC Berkeley

20

- Narrow particle size distribution

- Hollow interior

- Formation of Pt-skin with the thickness of 2ML

- Surfaces with 3D accessibility for reactants

- Segregated compositional profile with overall Pt3Ni composition

Science , 343 (2014) 1339

Compositional Profile: PtNi Nanoframes with Pt-skin Surfaces

21

Multimetallic Nanoframes with 3D Electrocatalytic Surfaces

Science , 343 (2014) 1339 22

Improving the ORR Rate by Protic Ionic Liquids

Erlebacher and Snyder, Advanced Functional Materials, 23(2013)5494

[MTBD][beti]

2

2 4

,[MTBD][ ]

O ,HClO

2.40 0.013O betiCC

= ±Pt/C np-NiPt/C np-NiPt/C+IL

0.95 V vs. RHE

Chemically Tailored Interface High O2 solubility along with hydrophobicity yield improved ORR kinetics

23

C - No change in activity after 10K cycles 0.6 – 1.0 V

- Mass activity increase over 35-fold vs. Pt/C

- Specific activity increase over 20-fold vs. Pt/C

- Increase in mass activity over 15-fold vs. DOE target

Science , 343 (2014) 1339

RDE @ 0.95V vs. RHE 0.1M HClO4 1600 rpm

RDE @ 0.90V vs. RHE 0.1M HClO4 1600 rpm

Tailoring Activity: PtNi Nanoframes as the ORR Electrocatalyst

24

Initial morphology

DURABILITY: Pt/C

After 60,000 cycles Potential Range: 0.6-1.0V

25

• Commercial catalysts are usually made by impregnation methods.

• Poor control – Broad size distribution – Different, undefined

morphologies, but everyone calls them “cubo-octahedral”, which is, in fact, not correct!

c d e

Commercial Pt/C Catalysts

26

Initial morphology

DURABILITY: Pt/C

After 60,000 cycles Potential Range: 0.6-1.0V

27

Initial morphology

DURABILITY: Pt/C

After 60,000 cycles Potential Range: 0.6-1.0V

27

SIZE EFFECT(s)? Pt/C

28

20 nm

cubo-octahedron truncated cube cube

• Uniform morphology • Size control octahedron (?) cubo-octahedral Cube

SHAPE EFFECT(s)? Pt/C

29

3 nm

2) Size distribution: 2-15 nm

1) Shape: cubooctahedron

3) Composition: Pt, C

4) Side Orientation: [111], [100]

HR-TEM: Characterization of Nanoscale Pt/C Catalyst

x 15

x 5

30

0.0 0.2 0.4 0.6 0.8 1.0

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

i [m

A/cm

2 ]

E [V vs RHE]0.0 0.2 0.4 0.6

-2.0x10-4

0.0

2.0x10-4

I/AE/V vs. RHE

[001]

(100)

(111)

APPROACH: Well-Defined Systems (ext & nano)

31

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0.925 V 0.900 V 0.875 V 0.850 V

Kin

etic

Cur

rent

Den

sity

[mA

/cm

^2]

Pt(110)Pt(111)Pt(100)Series4Pt-poly average

Detector

Quadrupole

Quadrupole allows single m/z pass at any given time Time frame for the range of m/z = 1 – 240 is 0.1sec

Quadrupole mass filter

Horizontal torch

ICP-MS: Principle of Operation

32

RDE/ICP-MS: Pt(hkl)

Rotating Disk Electrode

333

Standard Deviation σ=(Σ(µ-xi)2/n-1)1/2

λ (amu)

DL=3σbckg(λ)

Background

Method detection limit (DL) is applied to blank sample prepared

with all analytical steps related to given methodology, since each

step is potential error source

Limit of quantification (LOQ) is 3 times DL

Dissolved Pt per cycle [µML]

Pt Surface

Total Pt loss over one potential cycle up to 1.05 V for distinct Pt surface morphologies, indicating the stability trend follows the coordination number of the surface sites

Pt(111) 2

Pt(100) 7

Pt(110) 83

Pt-poly 36

Pt/C | 103*

In-Situ RDE / ICP-MS: Pt(hkl)-Surfaces vs. Pt/C

34

Pt/C | 103*

GC-Pt(4ML)

GC-Au-Pt(4ML)

In-Situ RDE / ICP-MS: Pt/C, Pt and Pt/Au Well-Defined Surfaces

35

DURABLE NPs: Core-Interlayer-Shell Particles

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-6-5-4-3-2-101234

i (m

A cm

-2)

E (V vs RHE)I want this blanked out!

I would love this area to blank outI would love this area to blank outI would love this area to blank outI would love this area to blank out

-80

-40

0

40

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

I (µA

cm

-2)

E (V vs RHE)

0

2

4

6

8

Au(111

)-Pt

3

2

Au(111

)-FeP

t 3

FePt 3

-poly

Pt-p

oly

1

Impr

ovem

ent F

acto

r vs

Pt P

oly

Spe

cific

Act

ivity

(iki

n/ m

Acm

-2)

Hupd

x 3

I II III IV

double layer Pt-OHad Au-OHad

Au(111)Au(111)-PtAu(111)-FePt3

A

ORR @ 0.9V

B

C

Nano Letters, 11 (2011) 919

NiPt3

36

DURABLE NPs: Core-Interlayer-Shell Particles

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

-6-5-4-3-2-101234

i (m

A cm

-2)

E (V vs RHE)I want this blanked out!

I would love this area to blank outI would love this area to blank outI would love this area to blank outI would love this area to blank out

-80

-40

0

40

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

I (µA

cm

-2)

E (V vs RHE)

0

2

4

6

8

Au(111

)-Pt

3

2

Au(111

)-FeP

t 3

FePt 3

-poly

Pt-p

oly

1

Impr

ovem

ent F

acto

r vs

Pt P

oly

Spe

cific

Act

ivity

(iki

n/ m

Acm

-2)

Hupd

x 3

I II III IV

double layer Pt-OHad Au-OHad

Au(111)Au(111)-PtAu(111)-FePt3

A

ORR @ 0.9V

B

C

Nano Letters, 11 (2011) 919

NiPt3

36

4nm

~ 5-6nm

Ni core

Au interlayer

PtNi shell 2 nm 2 nm

Monodisperse , Core/Interlayer/Shell NPs: Ni core / Au interlayer / PtNi shell

Compositional Profile: Core/Interlayer/Shell Electrocatalysts

37

Durable ORR Catalysts: Core/Shell NPs with Au Interlayer

- Pt - Au

segregation trend of Au onto surfacedriving force that diffuses Pt into the bulkdriving force induced by strong Pt - OHad interaction

- O

segregation trend of Pt into the bulk

- Fe- Ni

Stabilization mechanism

38 Nano Letters, 14 (2014) 6361

Nanoframes in 5cm2 MEA ANL and ORNL

Durable Systems: PtNi Nanoframes in MEA

Cathode Loading: 0.035 mg-Pt/cm2, I/C = 0.8 H2/O2, 80°C, 150 kPa(abs), 100%RH

ORR Activity @ 0.9V: Mass Activity x3.5 Specific Activity x6.5 TKK 20 wt%Pt/C: 0.22 A/mg-Pt 0.39 mA/cm2-Pt

PtNi Nanoframes: 0.76 A/mg-Pt 2.60 mA/cm2-Pt

in collaboration with Debbie Myers, ANL - CSE

39

Nanoframes in 5cm2 MEA ANL and ORNL

Durable Systems: PtNi Nanoframes (before and after)

0.1 µm

HAADF-STEM

0.1 µm

BF-STEM

membraneca

taly

st la

yer

membrane

5 nm

BF-STEM Pt Ni

5 nm

40

in collaboration with Debbie Myers, ANL - CSE

Cathode Loading: 0.046 mg-Pt/cm2 I/C = 1, H2/O2 (or Air), 80°C, 150 kPa(abs), 100%RH

0 500 1000 1500 2000 2500 30000.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

H2/O2 Performance

Commercial TKK Pt/C PtNi/C

IR c

orre

cted

Cel

l Vol

tage

(V)

Current Density (mA/cm2)0 300 600 900 1200 1500 1800

0.2

0.4

0.6

0.8

1.0

H2/Air Performance

Commercial TKK Pt/C PtNi/C

Cel

l Vol

tage

with

out I

R co

mpe

nsat

ion

(V)

Current Density (mA/cm2)

Units PtNi TKK Pt

Pt loading mgPGM/cm²geo 0.045 0.045

Mass Activity (H2-O2)

A/mgPGM @ 0.9 ViR-free

0.60 0.27

Specific Activity (H2-O2)

mA/cm2PGM

@ 0.9 ViR-free 1.85 0.39

MEA performance (H2-Air)

mA/cm2

@ 0.8 V 101 47

ECSA m2/gPGM 35.10 52.5

TKK 20 wt%Pt/C PtNi 16.7 wt%Pt/C

Durable Systems: PtNi with Multilayered Pt-Skin Surfaces

41

TM doped Pt3Ni Octahedra

Huang et al. Science , 348 (2015) 1230 SA and MA over 70-fold vs. Pt/C

Bu et al. Nat. Commun. , (2016) DOI 10.1038.natcomms11850

Hierachical PtCo Nanowires

SA and MA over 30-fold vs. Pt/C

Dealloying of PtNi octahedrons

Cui et al. Nature Mat., 12 (2013) 765 SA and MA over 10-fold vs. Pt/C

Alloying Pt with Rare Earth Elements

Escudero-Escribano et al. Science, 352 (2013) 73

SA over 6-fold vs. Pt/C

Greeley et al. Nature Chem., 1 (2009) 552

Pt/CuNW and PtNT

Alia et al. ACS Catalysis., 3 (2013) 358 SA and MA over 3-fold vs. Pt/C

Pt/CuNW

PtNT

BNL: Electrocatalyst Development

Remaining Challenges and Barriers

1) Durability of fuel cell stack (<40% activity loss)

2) Cost (total loading of PGM 0.125 mgPGM / cm2)

3) Performance (mass activity @ 0.9V 0.44 A/mgPt)

• Differences between RDE and MEA, surface chemistry, ionomer catalyst interactions

• Temperature effect on performance activity/durability

• High current density region needs improvements for MEA

• Support – catalyst interactions

• Scale-up process for the most advanced structures

Pt(hkl) with Ionomer

2x refers to the case of 10 µl of solution (0.005% wt.) applied to the electrode. Thickness can then be calculated by using a dry density of 1.5 g/cm3

49

Strongly Adsorbing Electrolytes: Improving the ORR Rate E [V vs. RHE]

0.0 0.2 0.4 0.6 0.8 1.0

Cur

rent

den

sity

[mA/

cm2 ]

-100

-50

0

50

100

Pt (111) - O2

- SO4 / PO4 2- 3-

Cyanide adlayer forms (2√3x 2√3)R30o structure on Pt (111) Itaya et al. J.Am.Chem.Soc. 118 (1996) 393

E [V vs. RHE]0.0 0.2 0.4 0.6 0.8 1.0

Cur

rent

den

sity

[mA/

cm2 ]

-6

-5

-4

-3

-2

-1

0

Pt (111)

- O2 - CN-

- SO4 / PO4 2- 3- Cyanides prevent the adsorption of sulfates/phosphates

~200 mV enhancement in the ORR

Nature Chemistry, 2 (2010) 880 50

57 2016 ECS Spring Meeting

Pt/HSAC Pt/Vulcan Pt/LSAC

• highly disordered with meso-graphitic outer ‘shell’ • Pt “inside” carbon particles

• concentric ‘domain’ structure ~4-5 nm graphite domain size

• Pt on surface of carbon particles

• highly ordered/faceted graphitic ‘shell’ with hollow

core • poor Pt surface dispersion

< <

Carbon Supports for Fuel Cell Catalysts

4nm 4nm 4nm

58 2016 ECS Spring Meeting

Imaging Catalyst Distributions in 3D

reconstructed volume (z-stack)

aligned HAADF tilt series

segmentation, visualization, and quantitative analysis

50 nm

50 nm

50 nm

• Quantify initial catalyst dispersions on different

carbon supports agglomeration • Elucidate catalyst degradation mechanisms (Pt agglomeration, coarsening, dissolution) AST for catalyst degradation 30,000 cycles 0.6-1.0V

• Improve stability and durability of

catalyst/support through structural optimization

SE HAADF STEM/EDS

59 2016 ECS Spring Meeting

Technical Accomplishments and Progress: Imaging Ionomer Dispersions in Catalyst Layers in 3D

17 MEA slices

Individual F maps acquired from “slices” are stacked to create a 3D rendering/reconstruction of the ionomer distribution within a given volume of the CL

1 µm

60 2016 ECS Spring Meeting

1 µm

200 nm

200 nm

single ~ 300 nm pore

Same pore with ionomer

200 nm

Technical Accomplishments and Progress: Imaging Ionomer Dispersions in Catalyst Layers in 3D

To correlate ionomer with porosity (and

simplify visualization), a single secondary pore

is selected from CL volume using

corresponding STEM images

Collaborations

Low-PGM Alloy Catalysts

Low-PGM Alloys

Advanced Catalyst Supports

Sub: synthesis, scale-up support Lead: design, synthesis, evaluation

Sub: catalyst supports Sub: structural characterization

Catalysts Scale Up

Lead: process R&D and scale-up

Sub: process support

MEA

Lead: 5 and 25cm2 MEA

Sub: 25 and 50cm2 MEA

OEMs

T2M

55

Collaborations

Single Crystals

Solid Nanoparticles

NPs with Skin Surfaces

Core-Shell NanoparticlesShaped Particles

Meso-S Thin FIlms

Nanoframes and Nanowires

H2O

H2

O2

A

anode

PEM

anode

H+ H+ H+ H+

H+

cathode

H+

Thin Films

55

RDE

MEA

Toyota - Mirai

A P P R O A C H

Full time postdocs:

Grad student: Nigel Becknell (synthesis, RDE, EXAFS)

Dongguo Li (RDE, synthesis, thin films) Haifeng Lv (RDE, synthesis, MEA) Rongyue Wang (scale up syntehsis, RDE, MEA)

Partial time postdocs: Pietro Papa Lopes (RDE-ICP-MS)

Partial time Staff: Paul Paulikas (UHV, thin films) Dusan Strmcnik

Collaborators: Guofeng Wang, University of Pittsburgh Jeff Greeley, Purdue University Plamen Atanassov, University of New Mexico Debbie Myers, Argonne National Laboratory Rod Borup, Los Alamos National Laboratory Karren More, Oak Ridge National Laboratory Peidong Yang, University of California Berkeley

Principal Investigators: Vojislav Stamenkovic Nenad Markovic

This research was supported by the Office of Science, Basic Energy Sciences, Materials Sciences Division and the Office of Energy Efficiency and

Renewable Energy of the U.S. Department of Energy

Chao Wang, ANL (Johns Hopkins University)

Dennis van der Vliet, ANL (3M)

Ramachandran Subaraman, ANL (Bosch Research Center)

Yijin Kang, ANL (UESR)

Nemanja Danilovic, ANL (ProtonOnSite)

Acknowledgments

Fuel Cell Technologies Office | 65

Thank you

hydrogenandfuelcells.energy.gov

Dimitrios Papageorgopoulos Program Manager – Fuel Cells

DOE Fuel Cell Technologies Office

Voya (Vojislav) Stamenkovic Argonne National Laboratory