1 Speaker: Chun-Yang Hsieh Advisor : Wen-Chang Wu Date : Preparation and Characterization of Pt/SnO 2 /C Cathode Catalyst for Proton Exchange Membrane Fuel Cell (PEMFC)

Introduction Review of the Literature Motivation Experimental Method Results and Discussion Conclusions Future Work Outline

Introduction 3 The fuel cell High power generation efficiency Wide range of applications No charge needed Wide fuel sources Low pollution

Introduction 4 Portable electronic products Transportation Generator

Introduction 5  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)

6 Introduction PEMFC High mobility High efficiency Cryogenic quick start Low pollution

Introduction 7 Catalyst Proton exchange membrane Catalyst

Introduction-CV 8

Introduction 9  Between Pt and SnO 2 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 Literature Motivation Experimental Results and discussion Conclusions Future work Outline

11 Review of the Literature The SiO 2 /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.

12 Review of the Literature Pt/SnO 2 shows the best performance in terms of both electrochemical activity, and stability against dissolution. Pt dissolution rates in Pt/SnO 2 are comparable to those of conventional Pt/C electrocatalysts.

Introduction Review of the Literature Motivation Experimental Results and discussion Conclusions Future work Outline

Motivation 14  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 TiO 2, Ti 0.7 W 0.3 O 2, and CeO x between others.  The higher electrochemical stability with SnO 2 can be attributed to the strong interaction between the Pt and SnO 2.

Motivation 15  This study strives to add the SnO 2 to increase the cathode catalyst activity and durability,and to assess the analysis to explore different SnO 2 / 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

17  SnCl 4 ‧ nH 2 O  NH 4 OH  Vulcan XC-72  H 2 PtCl 6 ·(H 2 O) 6  C 6 H 8 O 7  NaBH 4 Material

Fabrication of catalyst support Vulcan carbon distilled water and stirred for 30 min SnCl 4 ‧ 5H 2 O Tin oxide was formed upon precipitation 1M ammonium hydroxide filtered, and then washed copiously with de-ionized water stirred for 2 h placed in an oven at 80 ◦ C calcination SnO 2 /C

Fabrication of Pt supported over SnO 2 /C Aqueous solution of hexachloroplatinic acid stirred for 30 min citric acid stirred for 1 h SnO 2 /C support stirred continuously for 2 h NaBH 4 50mL de-ionized water 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/SnO 2 /C ， Pt/C

Introduction Review of the Literature Motivation Experimental Results and discussion Conclusions Future work Outline

21 Different pH Fig.1.XRD of SnO 2 (a) pH=2.0 (b) pH=4.0 (c) pH=8.0 (b) (a) (c) (110) (101) (200) (211) (220) (310) (301)

22 Different calcination temperature Fig. 2. XRD patterns of SnO 2 calcined at different temperatures （ a ） no calcined （ b ） 200 ℃ ( 1 deg/min).

23 Fig. 3. XRD patterns of SnO 2 calcined at different temperatures （ a ） 200 ℃（ b ） 300 ℃（ c ） 400 ℃（ d ） 500 ℃（ e ） 600 ℃（ f ） 700 ℃（ g ） 800 ℃ ( 4 deg/min). Different calcination temperature

24 Table.1. Effect of calcination temperature on grain size of SnO 2. Grain Size

25 Fig. 4.TEM images of SnO 2 /C nanopowder calcined at different temperatures （ a ） 200 ℃（ b ） 300 ℃（ c ） 500 ℃（ d ） 600 ℃（ e ） 800 ℃. TEM 17nm 7nm

26 Fig. 5. XRD of Pt/C and Pt/SnO 2 /C catalysts. XRD (111) (200) (220) (002)

27 Table.2. Grain size of Pt with different SnO 2 /C content. Grain Size Catalystsgrain size of Pt (nm) Pt/C12.7 Pt/10SnO 2 /70C10.2 Pt/20SnO 2 /60C8.5 Pt/40SnO 2 /40C7.7 Pt/60SnO 2 /20C7.4

28 Fig.6.TEM images of Pt/C and Pt/SnO 2 /C catalysts.

29 Fig.7.TEM images of Pt/C and Pt/SnO 2 /C catalysts. Ultrasonic wave Pt/C Pt/20 SnO 2 /60 C Ultrasonic wave

30 Fig 8. Cyclic voltammograms of Pt/C and Pt/SnO 2 /C in 0.5M H 2 SO 4 solution at 50 mVs -1. Electrochemical characterizations -0.2 ~ +0.2V H 2 desorption

31 Table.3.The electrochemical surface area of Pt/C and Pt/SnO 2 /C Electrochemical characterizations CatalystsEAS (cm 2 /mg) Pt/C59 Pt/10SnO 2 /70C102 Pt/20SnO 2 /60C195 Pt/40SnO 2 /40C228 Pt/60SnO 2 /20C123

32 Fig 7. With or without ultrasonic dispersion treatment of CV (a) Pt/C (b) Pt/10%SnO 2 /C (c) Pt/20%SnO 2 /C (d) Pt/40%SnO 2 /C (e) Pt/60%SnO 2 /C. Electrochemical characterizations

33 Table.4.The electrochemical surface area of Pt/C and Pt/SnO 2 /C Electrochemical characterizations Catalysts 無超音波之 EAS (cm 2 /mg) 有超音波 之 EAS (cm 2 /mg) Pt/C5989 Pt/10 SnO 2 /70 C Pt/20 SnO 2 /60 C Pt/40 SnO 2 /40 C Pt/60 SnO 2 /20 C123157

Introduction Review of the Literature Motivation Experimental Results and discussion Conclusions Future work Outline

Conclusions This study successfully used the precipitation method to prepare nano-tin dioxide powder. 2. Successfully used chemical reduction to prepared nanoscale Pt / SnO 2 / C catalyst powder 3. By using ultrasonic dispersion treatment, better dispersibility of the Pt / SnO 2 / C catalyst can be obtained in the preparation process

Conclusions Add a 40wt.% SnO 2 of Pt / SnO 2 / C catalysts to have a higher electrochemical active surface area, 228 cm 2 /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 / 40SnO 2 / 40C for 228 cm 2 / mg, after the ultrasonic treatment, EAS upgraded to 253 cm 2 / mg.

Introduction Review of the Literature Motivation Experimental Results and discussion Conclusions Future work Outline

38  The durability test.  Membrane electrode assembly (MEA) test. Future work

References 39  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 ( )  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 40