oxygen electrocatalysis · 2017-12-15 · cnt ‐npt chem. mater ... alkaline battery industrial...

Oxygen Electrocatalysis

C. R. Raj

Functional Materials and Electrochemistry Laboratory Department of Chemistry

Indian Institute of TechnologyKharagpur 721302, West Bengal, India

E‐mail: [email protected]://www.chem.iitkgp.ernet.in/faculty/CRR

iitkgp Workshop JNCSR Banglore, 27th November – 2nd December 2017

Sensors & Biosensors:Clinical and environmental

Energy Conversion & Storage: Fuel cell &

Supercapacitor

Synthesis:Chemical &

Electrochemical

0.0 0.2 0.4

Chem. Asian J. 2015, 10, 1554 ChemNanoMat 2015, 1, 615Biosens. Bioelectron. 2014, 62, 357 J. Mater. Chem. A, 2016, DOI :10.1039/c5ta08426aAnal. Bioanal. Chem. 2013, 405, 3431 J. Mater. Chem. A, 2014, 2,17848ACS Appl. Mater. Interface 2013, 5, 4791 J. Mater. Chem. A, 2014, 2, 2233Chem. Commun., 2011, 47, 11498 ACS Appl. Mater. Interfaces 2014, 6, 2692Chem. Commun., 2012, 48, 1787 Chem. Mater. 2010, 22, 4505Anal. Chem. 2008, 80, 4836 J. Phys. Chem. 2011, 115, 21041

Functional Materials and Electrochemistry Lab@ IITKgp

N

N

N

NS

OH

OH

N

N N

S

OH

OH

AcknowledgementMr. Bhaskar MannaDr. S. Bag (University of Calgary, Canada)Dr. Sourav Ghosh (TUM, Germany)Dr. Ramendra Sunder Dey (NSIT, India)Dr. Raj Kumar Bera (Hebrew University, Israel)Dr. Ashok Kumar Das (South Korea)Dr. Sudip Chakraborty (India)Dr. Bikash Kumar Jean (IMMT, India)Dr. Susmita Behera (UK)

Financial supportDST, CSIR and IIT Kharagpur

Mr. S. Bag Mr. B. Manna

Ms. S. Mondal Mr. A. Samanta

N

N

S

O

OHHO

N

N

N

NS

OH

OH

N

N N

S

OH

OH

N

N

S

OH

OH

Redox Molecular Assemblies: Electrochemically triggered Michael Addition Reaction on Au Surface

Langmuir 2007, 23, 1600J. Phys. Chem. C. 2008, 112, 3734

ACS Appl. Mater. Interfaces, 2010, 2 1355

J. Phys. Chem. C. 2007, 111, 15146

Functional Nanomaterial Library

Chem. Commun. 2005, 2005Anal. Chem. 2008, 80, 4836

Chem. Mater. 2008, 20, 3546

Anal. Chem. 2006, 78, 6332

J. Phys. Chem. C 2008, 112, 3496

nAu‐Enzyme nAu

nAu nAunPt

12/1/20175

Langmuir 2006, 112, 3734

nAu

J. Phys. Chem. C. 2011, 115, 21041

Patent: No. 36/KOL/2010Biosens. Bioelectron. 2010

J. Phys. Chem. C. 2010, 114, 21427

Au(III)

I-

Au(I)45 minSlow

disproportionation

Ag(I)

Nak

ed

Au

seed

s

12 h

No surfactants Room temperature

Fastdisproportionation

Fast

500 750 1000 1250

c

b

a

Disk

Ring

J. Mater. Chem. 2011, 21, 11973

CNT‐nPt

Chem. Mater. 2010, 12, 4505


nAgrGO‐nPtEnzyme‐ nPt

Nanotechnology 2012, 23, 385602

Cat. Sci. Tech. 2013, 3, 1078

Electrochim. Acta2013, 107, 592

CNT‐nPt‐Pd

nAu nPt

Chem. Commum. 2012, 48, 1787 Chem. Asian. J. 2012, 7, 417

Graphene


RSC Advance2013, 3, 25858

rGO‐ZnO

nAu

rGO‐Ni(OH)2

J. Mater. Chem. A. 2014, 2, 17848

rGO‐Mn3O4

ACS Appl. Mater. Interface 2014, 6, 2692

Fe

O

Fe

O

Biosens. Bioelectron. 2014, 62, 357

J. Chem. Sci. 2014ACS Appl. Mater. Interface 2013, 5, 4791

GO‐Fc

nPt‐nPd

rGO‐nPd


J. Mater. Chem. A 2014, 2, 2233

CNT‐nPtPd

Electrochim. Acta, 2015, 163, 16

ChemNanoMat 2015, 1, 615


J. Chem. Sci. 2016, 128, 339

Poly‐nAu

N‐rGO

SN‐rGO

J. Mater. Chem. A 2016, 4, 587

‐MnO2

‐MnO2

J. Mater. Chem. A 20164, 8384


Electrochemistry of Oxygen

Fuel Cell

Metal-Air Battery

Alkaline Battery

Industrial Process

Water Electrolysis

Ozone Generation

Zn-Air Battery

1.23 V

OER: 2H2O O2 + 4H+ + 4e

ORR: O2 + 4H+ + 4e 2H2O

E1/2

10 mA/cm2E

ORROER

Oxygen Electrocatalysis

O2 + 4H+ + 4e 2H2O

Oxygen Reduction Reaction

Noble Metal

Noble Metal‐free

Transition Metal Oxides

Metal‐free

Func

tion

al M

ater

ials f

or O

RR &

OER

Brief history of ORR

1823 1975 1980‐90 1993‐97 2000‐

1965 1975 1989‐92 2008‐ 2009‐

J. J. Lingane, J. Electroanal. Chem., 2 (1961) 296

ORR OER

Ideal bifunctional electrocatalyst:

(a) Onset PotentialIntersection of the tangents between the baseline and the rising current in the voltammogram

RDE

RRDE

OER

ORR: O2 + 4H+ + 4e 2H2O

OER: 2H2O O2 + 4H+ + 4e


(b) Current density (j)

Normalization with electrochemically active surface area (ECA) or mass

• Hydrogen adsorption/desorption• CO stripping• Underpotential deposition of Cu

210 C/cm2

Pure & Appl. Chern., Vol. 63, No. 5, pp. 71 1‐734, 1991


(b) Overpotential ()

= E‐Eeq

(c) Current density (j)OER: Benchmark current density: 10 mA/cm2

ORR: ?? ‐3 mA/cm2

OER Ideal: 200–300 mV Excellent: 300–400 mV Good: 400–500 mVSatisfactory: 500 mV

Nano Energy 37 (2017) 136–157

(d) Potential gap (E)

E = EOERj10 mA/cm2 – EORRj‐3mA/cm2

EOERj10 mA/cm2 – EORRj1/2

Caution:Potential gap should be made based on similar catalyst loading


(e) Tafel slope and exchange current density

Tafel slope: Small Exchange current density: High

Current density vs Overpotential at different exchange current density

O + ne ↔ R (n=1)

(f) Electron Transfer Number and % HO2−

Rotating disk electrode and Rotating ring‐disk electrodeKoutecky‐Levich Analysis

(g) Turn Over Frequency (TOF)

TOF = (j × A) (n × F × m)−1

n4

/ % 200

The Levich EquationVeniamin Grigorievich (Benjamin) Levichwas a leading scientist in electrochemicalhydrodynamics, ‐ invented and developedby him. The famous Levich equationdescribing a current at a rotating diskelectrode is named after him.

https://www.ceb.cam.ac.uk/research/groups/rg‐eme/teaching‐notes/hydrodynamic‐voltammetry

Kouteck-Levich AnalysisRDE

Rotating Ring-Disk Electrode Analysis

n4

/ % 200

What is happening at the ring?

Pure and Applied Chemistry 76(2):303‐319

Some Practical Notes

RDE Analysis: Does electrode preparation matters?

Ink Formulation

• Type of solvent, • Water/Solvent/Nafion content• Ultrasonication

Electrode surface

• Surface preparation: cleaning, polishing• Electrode material• Quality of film ‐ uniform

Deposition & drying

• Stationary/rotation• Temperature• Atmosphere – inert, gas flow rate

Ink Formulation: Electrochemically Active Surface Area (ECA) (for Pt only)

https://www1.eere.energy.gov

Film drying method: stationary vs rotational

J. Electroanal. Chem. 662, 2011, 396

Stationary Rotational

SEM: Surface SEM: EdgeSEM: Surface SEM: Edge

Ink Formulation and Drying: Electrocatalytic activity (for Pt only)

III

I s I r I r+iR II Nafion II

Does the quality of catalyst ink and film matters?

Ink Formulation and Film quality: ECA

Anal. Chem. 2010, 82, 6321

Does the catalyst ink and film quality has any impact?

Ink Formulation and Film quality: Electrocatalytic activity

Electrolyte purity and nature of anionOxygen purity

Durability

Pulse voltammetry

Chronoamperometry

Cyclic voltammetry

Loss of ECA: dissolution, re‐deposition‐ larger particle, aggregation

Post‐mortem analysis is critically required to evaluate the durability

Noble Metal

Noble Metal‐free

Transition Metal Oxides

Metal‐free

Func

tion

al M

ater

ials f

or O

RR

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Synthesis of Pt nanostructure in the absence of PDDA

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0.0 0.3 0.6 0.9 1.2 1.5

ba

E/V vs. SHE

ORR activity

10 nm 100 nm

Onset: 1.06 V

Pt loading 20 g/ cm2

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0

50

100

150

200

250

300

J k (A

/cm

2 )

0

10

20

30

40

50

I (A

/g)

Onset: 1.06 V

Pt loading 20 g/ cm2@ 0.9 V @ 0.9 V

Durability??

Kinetic current density: Mass activity:

44

Pt alloys are more active for oxygen reduction - Why?

* Inhibition of –OH species on Pt

* Shortening of Pt-Pt interatomic distance

* Increased d-band vacanciesCatalyst Pt-Pt

distance (Å)

Pt d-band vacancies

PtPt53Ni47

Pt51Fe49

Pt49Co51

Pt50Cr50

2.772.662.692.712.73

0.3700.3780.3900.3900.401

Mukerjee, et al. J. Electrochem. Soc., 1995,142, 1409

Order of oxide formation: Pt > Pt-Ni > Pt-Fe > Pt-Co > Pt-Cr

Order of oxygen reduction activity:Pt < Pt-Ni < Pt-Fe < Pt-Co < Pt-Cr

Shortening of Pt‐Pt interatomic distances ‐ Jalan and TaylorLattice contractions due to alloying – ApplebyFavorable Pt‐Pt distances at supported Pt binary alloys – Mukerjee and Srinivasan

45

Proposed mechanism for oxygen reduction on Pt alloys

* Increase of 5d vacancies led to an increased 2 electron donation from O2 to surface Pt and weaken the O-O bond

* As a result, scission of the bond must occur instantaneously as electrons are back donated from 5d orbitals of Pt to 2* orbitals of the adsorbed O2

Watanabe, et al. J. Electrochem. Soc., 1999, 146, 3750

1:1

1:0.5

0.5:1

Pt46Pd54

Pt64Pd36

Pt28Pd72

Pt/Pd

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Composition of catalyst

Molar ratio of Composition Precursors

Average size 10 nm.

Shape: Truncated octahedra, near spherical.

Uniform particle distribution.

Particles are inside the CNT as well as grafted on the wall.

Pt46Pd54

Elemental mapping

Characterization:

7 8 9 10 11 120

20

40

60

80

Diameter (nm)

Abu

ndan

ce (%

)

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ORR activity:

100

200

300

400

Pt-MCNT

Pt-Blac

k

J k (A

/cm

2 )

Pt 28Pd 72

Pt 64Pd 36

Pt 46Pd 54 0

20

40

60

80

100

120

Pt blac

k

Spherica

l nPt

Pt 46Pd 54

I (A

/g)

Kinetic current density: Mass activity:

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0.4 0.6 0.8 1.0

2.0

1.5

1.0

0.5

0.0

after cyclingbefore cycling

j (m

A/c

m2 )

E/V vs. SHE

Catalytic activity remains same after 1000 potential scan

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Highly cited paper (ISI web of knowledge)

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-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

j / m

A c

m-2

Potential vs SCE E/V

B

100 rpm40090016002500

N-rGO-Mn3O4

0

10

20

30

40

50

Current density

N-rGO/Mn3O4 Pt/CmixtureN-rGOMn3O4

n=3.96n=3.75

n=3.49

n=3.2

n=3.51

HO

2- yie

ld /%

HO2- yield

0.0

0.5

1.0

1.5

2.0

2.5

3.0

j /mA

cm-2

D

-0.6 -0.5 -0.4 -0.3 -0.20

4

8

12

Potential vs SCE E/ V

% o

f HO

2-

3.70

3.75

3.80

3.85

3.90

3.95

n

-0.8 -0.6 -0.4 -0.2 0.0 0.2

-2.0

-1.5

-1.0

-0.5

0.0

ab0.075 mA/cm-2

10 mV

j / m

A c

m-2

Potential vs SCE E/ V

B Durability

Metal‐free Electrocatalyst

Jahanke et al, Bagotskii et al and Fuhrmann A, Wiesener & Yeager’s group:Electrocatalytic ORR activity of nitrogen‐based catalyst ‐ pyrolysis ofmetallomacrocycles and acrylonitrile polymer and metal salts.

C.R.Raj and S. Bag, J. Chem. Sci. 2016

Electrocatalysts(N‐rGOs)

Onset potential(V)

Current densityAt 0.27

(mA/cm2)

N‐rGO1 0.55 1.64

N‐rGO2 0.58 1.94

N‐rGO3 0.66 2.71

N‐rGO4 0.66 2.76

Pyridinic: Limiting current

Graphitic: Onset potential

N‐doped reduced graphene oxideDoes the chemical nature of N impacts the ORR activity?

Nitrogen and Sulfur Dual‐Doped Reduced Graphene Oxide

C.R.Raj and S. BagElectrochimica Acta 2016

iit kgp

-0.6 -0.3 0.0 0.3Potential (vs Hg/HgO)

SN-rGO

N-rGO

S-rGO

rGO

50mA

S‐rGO & N‐rGO : 2 electron pathway SN‐rGO: mixed pathway

0

10

20

30

40

50

Pt/C

% of HO2-

n

S/N-rGON-rGO

n

% o

f HO

2-

S-rGO2.5

3.0

3.5

4.0

ACS Nano, 2014, 8, 6856

What is the active site? Pyridinic or graphitic??

What is the active site?

J. Am. Chem. Soc., 2014, 136, 10882FeNx/C Catalyst

Adv. Funct. Mater. 2017, 1700795

MO‐Co@N‐Doped Carbon

Emerging new generation electrocatalysts for the oxygen reduction reaction C. R. Raj et al. J. Mater. Chem. A, 2016, 4, 11156

Design of Efficient Bifunctional Oxygen Reduction/Evolution Electrocatalyst: Recent Advances and Perspectives, Adv. Energy Mater. 2017, 1700544

Electrocatalytic Oxygen Evolution Reaction in Acidic Environments – Reaction Mechanisms and Catalysts, Adv. Energy Mater. 2017, 7, 1601275

Oxygen Evolution Reaction Electrocatalysis on Transition Metal Oxides and (Oxy)hydroxides: Activity Trends and Design Principles, Chem. Mater. 2015, 27, 7549

Electrochemical Methods: Fundamentals and ApplicationsAllen J. Bard, Larry R. Faulkner

Modern ElectrochemistryBockris, John O'M., Reddy, AmulyaK.N., Gamboa‐Aldeco, Maria E.

What is the role of supporting electrolyte?

What is overpotential?

What are the different methods available for the measurement of ECA?

What is exchange current density?

What are the different modes of mass transport to electrode surface?

g{tÇ~ lÉâ12/1/2017

oxygen electrocatalysis · 2017-12-15 · cnt ‐npt chem. mater ... alkaline battery industrial...

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