Reporter ： Chun-Yang Hsieh Advisor ： Wen-Chang Wu Date ： 2014/3/26

1. Reporter：Chun-YangHsieh Advisor：Wen-Chang Wu Date：2014/3/26

2. Outline • Introduction • Material • Experimental • Results and discussion • Conclusions Results and discussion References Conclusions

3. Introduction • The high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) technology is particularly attractive for transportationapplication, because they do not use the conventional Nafionbased membranes and are exceptionally clean, producing noneof the harmful emissions generally associated with combustionengines. • Platinum based catalystsare recognized as the best electrocatalysts for use in PEMFCsand phosphoric acid fuel cells. • However, the success of the fuel cell commercializationmust entail the use of less expensive materials both in the electrolytemembrane and in the cathode catalyst. • Metal oxide-promoted Pt catalysts (PtWO3/C,PtMnO2/C, PtCrO2/C, PtV2O5/C) are more active than pure Ptcatalysts.

4. Introduction • This work focuses onthe preparation and characterization of Pt/SnOx/C, with varyingSnOcompositions, as cathode catalyst for PBI-based HT-PEMFC. • Fuel cell performance measurements, in the temperature regime160–200 ◦C, and durability test up to 200 h were done in ordertodetermine their stability and feasibility as cathode catalyst forHT-PEMFCs.

5. Outline • Introduction • Material • Experimental • Results and discussion • Conclusions Results and discussion References Conclusions

6. Materials • SnCl2 • Carbon black (Vulcan XC-72R) • ammonium hydroxide • H2PtCl6·(H2O)6 • NaBH4

7. Outline • Introduction • Material • Experimental • Results and discussion • Conclusions Results and discussion References Conclusions

8. Fabrication of catalyst support 1 g of Vulcancarbon SnCl2 150mL distilled water and stirred for 30 min 20mL1M Ammonium hydroxide Tin oxide was formed uponprecipitation of Sn2+ stirred for 2 h filtered, and then washed placed in an oven at 150 ◦C

9. Pt supported over SnO/C Aqueous solution of hexachloroplatinic acid (100 mL) 0.3 g of NaBH4 stirred for 30 min 0.3 g of SnO/C support 50mL de-ionized water stirred for 1 h stirred continuously for 2 h the suspension was filtered, washed copiously dried

10. Outline • Introduction • Material • Experimental • Results and discussion • Conclusions Results and discussion References Conclusions

11. Results and discussion Pt(111) Pt (311) Pt (220) Pt (200) Pt(222) Fig. 1. XRD of Pt/SnO/C catalyst.

12. Results and discussion • Fig. 2. TEM of Pt/SnO/C catalyst (scale bar 30 nm). • .

13. Results and discussion Fig. 3. SEM and EDX of Pt/SnO/C catalyst (scale bar 200 nm).

14. Results and discussion Fig. 4. Polarization curves of PBI-based MEAs at 180 ◦C using of Pt/SnO/C catalystat the cathode. H2 (dry) stoichiometric ratio: 1.2; O2 (dry) stoichiometric ratio:2;minimum flow at the anode: 0.1 Lmin−1;minimum flow at the cathode: 0.2 Lmin−1;pressure: 1 atm; Pt loading (anode and cathode): 0.5mgcm−2.

15. Results and discussion • Fig. 5. Nyquist plots showing the effect of the concentration of SnO on (a)electrochemical reaction resistance and (b) cathode mass-transfer resistances. Temperature180 ◦C. H2 stoichiometric ratio: 1.2; O2 stoichiometric ratio: 2; minimumflow at the anode: 0.1 L min−1;minimum flow at the cathode: 0.2 L min−1; pressure:1 atm; Pt loading (anode and cathode): 0.5mgcm−2

16. Results and discussion Fig. 6. Polarization curves of PBI-based MEAs manufactured using 40 wt.%Pt/7%SnO/53%C catalyst. H2 (dry) stoichiometric ratio: 1.2; O2 (dry) stoichiometricratio: 2; minimum flow at the anode: 0.1 Lmin−1; minimum flow at the cathode:0.2 Lmin−1; pressure: 1 atm; Pt loading (anode and cathode): 0.5mgcm−2.

17. Results and discussion Fig. 7. Durability of MEA prepared using 40 wt.%Pt/7%SnO/53%C catalyst. H2(dry)stoichiometric ratio: 1.2; O2 (dry) stoichiometric ratio: 2; minimum flow at theanode: 0.1 Lmin−1; minimum flow at the cathode: 0.2 L min−1; pressure: 1 atm; Ptloading (anode and cathode): 0.5mgcm−2.

18. Results and discussion Fig. 8. Polarization curves of MEA prepared using 40wt.%Pt/7%SnO/53%C catalyst,before and after durability experiment for 200 h. H2 (dry) stoichiometric ratio: 1.2;O2 (dry) stoichiometric ratio: 2; minimum flow at the anode: 0.1 Lmin−1;minimumflow at the cathode: 0.2 Lmin−1; pressure: 1 atm; Pt loading (anode and cathode):0.5mgcm−2.

19. Results and discussion Fig. 9. Nyquist plots at 0.1A (activation region) and 1.25A (mass-transfer region)before and after durability experiment at 180 ◦C during 200 h. H2 stoichiometricratio: 1.2; O2 stoichiometric ratio: 2; minimum flow at the anode: 0.1 L min−1;minimum flow at the cathode: 0.2 L min−1; pressure: 1 atm; Pt loading (anode andcathode): 0.5mgcm−2.

20. Outline • Introduction • Material • Experimental • Results and discussion • Conclusions Results and discussion References Conclusions

21. Conclusions • Hightemperature PEMFC measurements performed using PBI-basedMEAs showed good performance when using catalysts containing7wt.% SnO in the cathode. • With higher concentrations of tin oxide theperformance decreased as a result of mass transport limitationswithin the electrode, as confirmed by impedance spectroscopymeasurements. • Durability tests performed during a 200 h time interval at 180 ◦Cand 200mAcm−2 showed that Pt/SnO/C catalysts were stableunder fuel cell working conditions. • The good performance anddurability of the Pt/SnO/C catalysts make them good alternativesfor cathodes for high temperature PEMFCs.

22. Thanks For Your Attention!!