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Speaker: Chun-Yang Hsieh

Advisor : Wen-Chang Wu

Date : 2015.04.08

Preparation and Characterization of Pt/SnO2/C Cathode Catalyst for Proton Exchange Membrane

Fuel Cell (PEMFC)

IntroductionReview of the Literature

Motivation

Experimental Method

Results and Discussion

Conclusions

Future Work

Outline

Introduction

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The fuel cell

High power generation efficiency

Wide range of applications

No chargeneeded

Wide fuel sources

Low pollution

Introduction

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Portable electronic products

Transportation

Generator

Introduction

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There are several different kinds of fuel cells .

Alkaline fuel cell (AFC)

Phosphoric acid fuel cells (PAFC)

Molten Carbonate Fuel Cell (MCFC)

Solid Oxide Fuel Cell (SOFC)

Proton Exchange Membrane Fuel Cell (PEMFC)

Direct methanol fuel cell (DMFC)

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Introduction

PEMFC

High mobility

High efficiency

Cryogenic quick start

Low pollution

Introduction

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Catalyst

Proton exchange membraneCatalyst

Introduction-CV

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Introduction

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Between Pt and SnO2 there is a strong interaction, this phenomenon is sometimes explained as strong metal–support interaction (SMSI).

This interaction can inhibit the Pt metal corrosion.

It has also been found that SMSI has an increase in activity for oxygen reduction effect.

The real mechanism of SMSI is not always clear for several catalyst systems.

Introduction

Review of the LiteratureMotivation

Experimental

Results and discussion

Conclusions

Future work

Outline

11

Review of the Literature

The SiO2/Pt/C catalyst exhibited higher durability than the Pt/C one, due to the facts that the silica layers covered were beneficial for reducing the Pt aggregation and dissolution as well as increasing the corrosion resistance of supports.

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Review of the Literature

Pt/SnO2 shows the best performance in terms of both electrochemical activity, and stability against dissolution. Pt dissolution rates in Pt/SnO2 are comparable to those of conventionalPt/C electrocatalysts.

Introduction

Review of the Literature

MotivationExperimental

Results and discussion

Conclusions

Future work

Outline

Motivation

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The life span of the Pt catalyst is reduced because of CO poisoning, Pt dissolution and carbon corrosion of the support substrate.

The literature indicates oxide can improve the durability of TiO2, Ti0.7W0.3O2, and CeOx between others.

The higher electrochemical stability with SnO2 can be attributed to the strong interaction between the Pt and SnO2.

Motivation

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This study strives to add the SnO2 to increase the cathode catalyst activity and durability,and to assess the analysis to explore different SnO2 / C composition ratio and other parameters the catalytic activity and electrochemical stability.

Introduction

Review of the Literature

Motivation

Experimental Method Results and discussion

Conclusions

Future work

Outline

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SnCl4 nH‧ 2O

NH4OH

Vulcan XC-72

H2PtCl6·(H2O)6

C6H8O7

NaBH4

Material

Fabrication of catalyst support

Vulcan carbon

distilled water and stirred for 30 min

SnCl4 5H‧ 2O

Tin oxide was formed upon precipitation

1M ammonium hydroxide

filtered, andthen washed copiously with

de-ionized water

stirred for 2 h

placed in an oven at 80 ◦C

calcination

SnO2/C

Fabrication of Pt supported over SnO2/C

Aqueous solution of hexachloroplatinic acid

stirred for 30 min

citric acid

stirred for 1 h

SnO2/C support

stirred continuously for 2 h

NaBH4

50mL de-ionizedwater

filtered, washed

placed in an oven at 80 ℃ to get the final product

Ultrasonic wave

filtered, washed

placed in an oven at 80 ℃ to get the final product

Pt/SnO2/C， Pt/C

Pt/SnO2/C， Pt/C

Introduction

Review of the Literature

Motivation

Experimental

Results and discussionConclusions

Future work

Outline

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Different pH

Fig.1.XRD of SnO2 (a) pH=2.0 (b) pH=4.0 (c) pH=8.0

(b)

(a)

(c)(110)

(101)(200)

(211)

(220) (310)(301)

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Different calcination temperature

Fig. 2. XRD patterns of SnO2 calcined at different temperatures （ a ） no calcined （ b ） 200℃ (1 deg/min).

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Fig. 3. XRD patterns of SnO2 calcined at different temperatures （ a ） 200℃ （ b ） 300℃ （ c ） 400℃ （ d ）500℃ （ e ） 600℃ （ f ） 700℃ （ g ） 800℃ (4 deg/min).

Different calcination temperature

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Table.1. Effect of calcination temperature on grain size of SnO2.

Grain Size

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Fig. 4.TEM images of SnO2/C nanopowder calcined at different temperatures （ a ） 200℃ （ b ） 300℃ （ c ） 500℃（ d ） 600℃ （ e ） 800℃.

TEM

17nm

7nm

26Fig. 5. XRD of Pt/C and Pt/SnO2/C catalysts.

XRD

(111) (200)(220)(002)

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Table.2. Grain size of Pt with different SnO2/C content .

Grain Size

Catalysts grain size of Pt (nm)

Pt/C 12.7

Pt/10SnO2/70C 10.2

Pt/20SnO2/60C 8.5

Pt/40SnO2/40C 7.7

Pt/60SnO2/20C 7.4

28Fig.6.TEM images of Pt/C and Pt/SnO2/C catalysts.

29Fig.7. TEM images of Pt/C and Pt/SnO2/C catalysts.

Ultrasonic wave

Ultrasonic wave

Pt/C

Pt/20 SnO2/60 C

Ultrasonic wave

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Fig 8. Cyclic voltammograms of Pt/C and Pt/SnO2/C in 0.5M H2SO4 solution at 50 mVs-1.

Electrochemical characterizations-0.2 ~ +0.2V

H2 desorption

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Table.3.The electrochemical surface area of Pt/C and Pt/SnO2/C

Electrochemical characterizations

Catalysts EAS (cm2/mg)

Pt/C 59

Pt/10SnO2/70C 102

Pt/20SnO2/60C 195

Pt/40SnO2/40C 228

Pt/60SnO2/20C 123

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Fig 7. With or without ultrasonic dispersion treatment of CV (a) Pt/C (b) Pt/10%SnO2/C (c) Pt/20%SnO2/C (d) Pt/40%SnO2/C (e) Pt/60%SnO2/C .

Electrochemical characterizations

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Table.4.The electrochemical surface area of Pt/C and Pt/SnO2/C

Electrochemical characterizations

Catalysts 無超音波之 EAS

(cm2/mg)

有超音波 之 EAS

(cm2/mg)

Pt/C 59 89

Pt/10 SnO2/70 C 102 121

Pt/20 SnO2/60 C 195 222

Pt/40 SnO2/40 C 228 253

Pt/60 SnO2/20 C 123 157

Introduction

Review of the Literature

Motivation

Experimental

Results and discussion

ConclusionsFuture work

Outline

Conclusions

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1. This study successfully used the precipitation method to prepare nano-tin dioxide powder.

2. Successfully used chemical reduction to prepared nanoscale Pt / SnO2 / C catalyst powder

3. By using ultrasonic dispersion treatment, better dispersibility of the Pt / SnO2 / C catalyst can be obtained in the preparation process

Conclusions

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4. Add a 40wt.% SnO2 of Pt / SnO2 / C catalysts to have a higher electrochemical active surface area, 228 cm2/mg than owned Pt / C catalyst.

5. The electrochemical active surface of the ultrasonic dispersion treatmented cathode catalyst is higher than without treatment, has the best EAS value of Pt / 40SnO2 / 40C for 228 cm2 / mg, after the ultrasonic treatment, EAS upgraded to 253 cm2 / mg.

Outline

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The durability test.

Membrane electrode assembly (MEA) test.

Future work

References

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Takeoh Okanishi, Toshiaki Matsui, Tatsuya Takeguchi ,Ryuji Kikuchi, Koichi Eguchi. Chemical interaction between Pt and SnO2 and influence on adsorptive properties of carbon monoxide. Applied Catalysis A: General 298 (2006) 181–187.

Y. Takabatake , Z. Noda , S.M. Lyth , A. Hayashi , K. Sasaki . Cycle durability of metal oxide supports for PEFC electrocatalysts. i n t e rna t i o n a l journa l o f hydrogen energy xxx ( 2 0 1 4 ) 1 -9.

衣寶廉，「燃料電池－原理與應用」，五南圖書出版股份有限公司，民 95年。 黃鎮江，「燃料電池」，全華科技圖書股份有限公司，民 92 年。

Thanks for your attention

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