university of delaware – 2013 ccst annual review...(5-year-average: 2007/09-2012/09, from ) 14...

University of Delaware – 2013 CCST Annual Review

Toward a Distributed Renewable Electrochemical Energy and Mobility System (DREEMS)

• Electrochemical devices, e.g., fuel cells, electrolyzers, flow batteries, …

• Electrocatalysis• Polymer electrolytes• Electrochemical Interfaces

1

@Energy Inst, Texas A&M U

10/20/2015

Yushan YanDepartment of Chemical and Biomolecular Engineering

University of Delaware

3

Energy Today

Electricity is the most convenient form of energy

4

• ~40% today • ~70% if transportation is electrified

5

Electricity TodayCombustion

6

• Fuel cell• Electrolyzer• Flow battery

Electricity Tomorrow

Electrochemical Conversion

Gu, Xu, Yan, Annual Review of Chemical and Biomolecular Engineering, 2014, DOI 10.1146/annurev-chembioeng-060713-040114

Energy RevolutionToday• Centralized

– Large combustion power plants

Tomorrow • Distributed

– Networked electrochemical devices

Computing RevolutionYesterday• Centralized

– Large mainframe computers

Today • Distributed

– Networked personal computers

What is the difference between combustion and electrochemical conversion?

8

Combustion

e-Fuel loses electrons and is oxidized

O2 takes electrons and is reduced

• Redox• Direct e-exchange• Irreversible• C CO2

H2 + ½ O2 H2O

Proton Exchange Membrane Fuel Cell (PEMFC)

10

H2 + ½ O2 H2OHydrogen oxidationH2 2H+ + 2e-

Oxygen reduction½ O2 + 2e- + 2H+ H2O

• Redox• Indirect e-exchange• Reversible• High efficiency to e• H2 Zero CO2

Electrochemical Conversion

11

PEMFC has been successfully used in commercially produced cars!

PEMFC Economics

13

• Commercialization barriers:– Cost– Durability

• Solution: – Switch acid to base so that non-

precious-metal catalysts and inexpensive membranes can be used

• Pt: $2,200/oz• Ni: $0.56/ozMetal prices(5-year-average: 2007/09-2012/09, from www.metalprices.com)

http://www.metalprices.com/

1414

Fuel Cells

Gu, Xu, Yan, Annual Review of Chemical and Biomolecular Engineering, 2014, DOI 10.1146/annurev-chembioeng-060713-040114

Hydroxide Exchange Membrane Fuel Cell (HEMFC)

15H2 + ½ O2 H2O

Polymer Hydroxide Exchange Membranes:

Quaternary Phosphonium Cation

16

n

OH-

O O

CH3

CH3

S

O

O

CH2

CH3CH3

CH3

N+

nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-R4N+: • Low OH- conductivity• Low stability

Gu et al. Angew Chem Int Ed 2009

Basicity

W.A. Henderson, et. al, J. Am. Chem. Soc , 82 (1960) 5791−5794

• RNH2• R2NH• R3N

• R3P• R2PH• RPH2

18

nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-

W.E. McEwen, et al., J Am. Chem. Soc. 1965 (87) 3948

Stability

19

S. Gu et al. ChemSusChem 2010S. Gu et al. Angew. Chem. Int. Ed. 2009

20

S. Gu et al. ChemSusChem 2012 S. Gu et al. Chem. Commu. 2013

21

Quaternary Phosphonium CationHow stable is it?

Are the 9-MeO groups necessary?How does it degrade?

How can we improve its stability?

nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-

22Unpublished results

Durability test of TPQP @ 80 oC

• T= 80 oC, KOD: 1M• Model compound: TPQP (1 mmol)• Alkali: KOD (30 mmol)• Solvent: CD3OD/D2O (v/v=5/1)• Internal standard: 3-(trimethylsilyl)-1-propanesulfonic acid

sodium salt (0.49 mmol)

Testing conditions

TPQP


TPQP vs BTMA @ 80 oC





nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-

25

Durability test of QP analogs @ 20 oC

• T= 20 oC, KOD: 1M• Model compound: QP analogs (1 mmol)• Alkali: KOD (30 mmol)• Solvent: CD3OD/D2O (v/v=5/1)• Internal standard: 3-(trimethylsilyl)-1-propanesulfonic acid

sodium salt (0.49 mmol)

Testing conditions

TPP 3MeTPP 3MeOTPP


Increasing e– donation

QP analogs @ 20 oC


28

TPQP vs QP analogs

Unpublished results




nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-


P+ degradation mechanism

30

KOH +

R=H, Me, OMe

Common P+

TPQP

Unpublished results




nO O

CH3

CH3

S

O

O

CH2

P+

H3CO

H3CO

OCH3

OCH3

OCH3

H3CO

H3CO OCH3

OCH3

OH-


32

Permethylcobaltocenium (Cp*2Co+)

Cation

Gu et al. Scientific Reports 2015

The Ideal Cation

34

K+Co+

CH3

CH3 CH3

CH3 CH3

CH3

CH3CH3

CH3 CH3

2


Synthesis of Cp*2Co+-PSf

35Gu et al. Scientific Reports 2015

Alkaline stability of Cp*2Co+-PSf & other

HEMs

36

0 20 40 60 80 100 1200

500

1000

1500

2000 Cobaltocenium Ammonium Imidazolium Guanidium Pyridinium Phosphonium Sulfonium Ruthenium

HEM

lifet

ime /

hou

r

Temperature / °C


Catalysts

37

• In base– ORR is NOT a problem!!!– But HOR is!!!

Observation

38

• HOR on Pt is 200 times slower in base than in acid– Why?– How can we get a good non-precious metal

HOR catalyst?

HOR/HER Mechanism

39

adHH 2*22 ⇔+

−+ ++⇔ eHHad *

−+ ++⇔+ eHHH ad*2

Tafel

VolmerHeyrovsky

Tafel – VolmerTafel – Volmer

Heyrovsky – VolmerHeyrovsky – Volmer

Hydrogen binding energy (HBE) is the descriptor of HER/HOR in acid

40

Volcano plot

Strongly bonded Weekly bonded

Nørskov et al., Journal of Electrochemical Society, 2005, 152 (3), J23-J26

Volcano plot of HER in base

41

Sheng et al., Energy & Environmental Science, 2013, 6(5), 1509-1512

Correlating HOR/HER activity to experimentally measured HBE

42

• Previous two studies correlate HOR or HER to calculated HBEs

• Only two fixed pHs (e.g., 1 and 13)

Sheng et al. Nature Communications 2015

How to measure HBE experimentally?• Cyclic voltammetry (CV)

43

𝐸𝐸𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝,𝑅𝑅𝑅𝑅𝑅𝑅 = −∆𝐺𝐺Had

0

𝐹𝐹

∆𝐺𝐺0

1/2𝐻𝐻2 ↔ 𝐻𝐻+ + 𝑒𝑒 0

1/2𝐻𝐻2 + ∗ ↔ 𝐻𝐻𝑝𝑝𝑎𝑎 ∆𝐺𝐺Had0

𝐻𝐻𝑝𝑝𝑎𝑎 ↔ 𝐻𝐻+ + 𝑒𝑒 + ∗ −∆𝐺𝐺Had0

𝐸𝐸𝑀𝑀−𝑅𝑅 = ∆𝐻𝐻10

= −𝐸𝐸𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝐹𝐹 −12𝑇𝑇𝑆𝑆𝑅𝑅2

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-0.02

0.00

0.02

(100)

I (m

A)

E vs RHE (V)

Pt disk

0.1 M KOH, Ar, 50 mV/s

(110)Hupd desorption

Hupd adsorption

Double layer region

Pt-OHad

Pt-O reduction

Pt oxidation

CV of Pt disk in different pH

44

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-40-30-20-10

010203040

i (µA

)

E (V vs. RHE)

acetate buffer (pH=5.2)phosphate buffer (pH=6.7)

(bi)carbonate buffer (pH=10.7)

KOH (pH=12.8)

HClO4 (pH=0)

Sheng et al. Nature Communications 2015


45


Pt


Hydrogen binding energy (HBE) is the

descriptor of

HER/HOR

460.1 0.2 0.3 0.4 0.5

-0.03

-0.02

-0.01i HE

R = −

1 m

A/cm

2 disk

HBE (eV)

(110) (100)

HER0.00

0.01

0.02

0.03

0.04

0.05

i HOR =

0.5

i lim

η (V

vs.

RHE

)HOR

Sheng, … Chen, Yan Nature Communications 2015


47


Pt

Au


NON-PRECIOUS METAL CATALYSTS

48

Non-previous metals for HOR/HER

49

Strongly bonded

HBE (eV) Binding site

Mo (110) -0.70 bridge

Ni (111) -0.51 fcc

NiML/Mo (110) -0.40 bridge

CoNi/Mo (110) -0.43 bridge

Pt (111) -0.46 fcc

HER/HOR activity of Ni may be enhanced by Mo and Co.

CoNiMo

50

ΔEH can be useful as a designing principle

Sheng et al., Energy & Environmental Science, 2014, 7,1719

20 time of Ni

Simulated fuel cell performance

51Zhuang, … Yan, Unpublished results

Simulated polarizationcurves of Ni/N-CNT HEMFC(blue line) and Ni HEMFC(orange line). Anode catalystis Ni/N-CNT or Ni with aloading of 5 mgNi/cm2.Cathode catalyst is N-Fe-CNT/CNP[9] (5 mg/cm2) andcell resistance is 0.07 Ω cm2

[8] and cell temperature is 80°C. The circles stand for thecell operating at 0.1 Voverpotential on anode sideand the stars at 0.15 V. Thenumbers are the peak powerdensity. The green line isstate-of-the-art PEMFC with0.15 mg Pt /cm2.[1]

Summary

52

• Phosphonium is a promising cation for HEMs.

• HBE is likely to be the sole descriptor for HOR and HER for monometallic catalyst.

• Sufficiently active non-precious metal HOR catalysts are demonstrated, but their stability needs improvement (e.g., 0.2 V vs. RHE).

• HEMFCs are commercially viable.

Electrochemical Energy Engineering: A New Frontier of Chemical Engineering Innovation

• Electrocatalysis• Polymer electrolytes• Electrochemical interfaces

• Electrochemical devices, e.g., fuel cells, electrolyzers, solar hydrogen, flow batteries, …

53Gu, Xu, Yan, Annual Review of Chemical and Biomolecular Engineering, 2014, DOI 10.1146/annurev-chembioeng-060713-040114

54

• Current postdoctoral fellows/professional researchers1. Junhua Wang2. Yun Zhao3. Hongxia Guo4. Yan Wang5. Yancai Li

• Former postdoctoral fellows (current position)1. Zhengbao Wang (Prof, Zhejiang U, China)2. Xiaoliang Cheng (Dofasco, Canada)3. Limin Huang (Prof. SUSTC, China)4. Anupam Mitra (Bussan Nanotech, Japan)5. Huanting Wang (Prof, Monash U, Australia)6. Cheng Wang (Prof, CAS, China)7. Hongmei Luo (Prof, New Mexico State U)8. Shuang Li (Henkel Tech)9. Xin Wang (Prof, Nanyang Tech U, Singapore )10. Weiqiao Deng (w/i Goddard) (Prof, CAS, China)11. Yachun Mao (Prof, Harbin Inst Tech, China)12. Tiger Jeong (w/i Hoek) (Hyundai, Korea)13. Youngseok Kim (Samsung, Korea)14. Wenzhen Li (Prof, Iowa State U)15. Lianbin Xu (Prof, Beijing U Chem Tech, China)16. Derek Beving (UCR)17. Tierui Zhang (Prof, CAS, China)18. Christopher Lew (Chevron)19. Rui Cai (Prof, CAS, China)20. Feng Wang (Enogetek)21. Qian Xu22. Shaun Alia (NREL)23. Stephanie Goubert-Renaudin (UCSB)24. Min-Rui Gao (Prof, U of Science and Tech of China)25. Jun Jiang 26. Wenchao Sheng (Columbia/Brookhaven Nat Lab)27. Zhongbin Zhuang (Prof, Beijing U of Chem Tech, China)28. Qianrong Fan (Prof, Jilin U, China)29. Shuang Gu (Prof, Wichita State U)

• Former visiting scholars1. Dongyuan Zhao (Prof, Fudan University)2. Huaiyong Zhu (Prof. Queensland U Tech, Australia)3. Silmook Lim (Prof, Korean Polytech U, Korean)4. Gaohong He (Prof. Dalian U Tech)5. Lin Zhang (Prof. Zhejiang U, China)6. Liping Zhu (Prof. Zhejiang U, China)7. Yu Zhang (Prof. Jilin U of Chem Tech, China)8. Hua Li (Prof. Minzhu Univ, China)9. Jianyu Cao (Prof. Changzhou U, China)10. Haiyun Zhang (Prof. Shanghai, China)

• Current graduate students1. Jie Zheng2. Jarrid Wittkopf3. Ke Gong4. Mariah Woodroof5. Andrew Tibbits (w/Kloxin)6. Rose Ma7. Marco Dunwell (w/Xu)8. Stephen Giles (w/Vlachos)9. Hao Wang10. Jared Nash (w/Xu)11. Zili Yao (w/T. Xu)

• Former graduate students (current position)1. Tiegang Cao (Krieger & Stewart)2. Jinfeng Zhao (UC Davis)3. Anthony Avila (with Deshusses)4. Brett Holmberg (NanoH2O)5. Zijian Li (HRL)6. Dora Medina (Prof. Tecnológico de Monterrey)7. Ronnie Munoz ()8. Mahesh Waje (Lynn Tech)9. Jason Tang (with Haddon) (Navy) 10. Derek Beving (UCR)11. Paul Larsen12. Joseph Steirer (York Engineering)13. Zhongwei Chen (Prof. U Waterloo)14. Gang Zhang (Prof. Jilin Univ)15. Shuang Gu ( Prof. Wichita State)16. Christopher Lew (Chevron)17. Wayne Sun (ESPR)18. Jennie Liu19. Rajwant Bedi (CA EPA)20. Ting Luo (UCR)21. Lei Xie (KAUST)22. Kurt Jensen (Riverside City)23. Shaun Alia (NREL)24. Jie Zhao (Sinopec, China)25. Mellisa Gettel26. Yanqi Zhang 27. Shuyuan Zhou 28. Laj Xiong29. Elizabeth Mahoney (ExxonMobil)30. Bingzi Zhang (Beijing U of Chem Tech)31. Robert Kaspar32. Mingchuan Luo

• Financial supports– EPA-NSF/TSE– NSF/Sensor Network– NSF/NIRT– DoD/SERDP– DoD/TACOM– DOE/Hydrogen Initiative– DOE/EERE– DOE/ARPA-E 2009 OPEN– DoD/MURI– DOE/ARPA-E 2012 OPEN

– California Energy Commission– Riverside Public Utilities

– AMD– Intel– AlliedSignal/Honeywell– Asahi Kasei Corporation– Engelhard Corporation– United Technologies– Ford Motor Company– Pacific Fuel Cells Corp.– SRC

– UC-Discovery Grant– UC-TSR&TP– UC-EI– UC-Water Resources Center– Calspace

university of delaware – 2013 ccst annual review...(5-year-average: 2007/09-2012/09, from ) 14...

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