Electrochemical and impedance spectroscopy studies in H2/O2 and methanol/O2 proton exchange membrane fuel cells
Tóm tắt
This works report results of the structural and the electrochemical characterization of membrane electrode assemblies (MEA) for proton exchange membrane fuel cells (PEMFC) under various cell conditions using different MEA production processes. Electrochemical impedance spectroscopy (EIS) was applied “on-line” (in situ) as a tool for diagnosis concerning the cell performance. MEA with a 25-cm2 surface area were prepared using Pt/C and Pt–Ru/C commercial electrocatalysts from E-TEK and Pt–Ru/C electrocatalysts produced by the alcohol reduction process. The catalytic ink was applied directly onto the carbon cloth or, alternatively, onto the Nafion® membrane. Two carbon cloth thicknesses were tested as diffusion layers in the MEA: 0.346 mm (common) and 0.424 mm (ELAT). An increase of the electrocatalytic activity can be obtained by pH control in the alcohol reduction process, possibly due to the better particle dispersion and the smaller particle sizes observed. In addition, a slower current decay in the ohmic region was observed using the thinner carbon cloth. This can be related to a lower resistance of the gas flow through the cloth to the catalytic active layer. Different types of methanol feed were employed in the experiments: by humidification and by evaporation. The results showed that the choice of suitable methods for catalyst preparation as well as for MEA production enhance PEMFC performance.
Tài liệu tham khảo
Wendt H, Götz M, Linardi M (2000) Quím Nova 23:538
Frey T, Linardi M (2004) Electrochim Acta 50:99
Franco EG, Oliveira-Neto A, Aricó E, Linardi M (2002) J Braz Chem Soc 13:516
Camara GA, Giz MJ, Paganin V, Ticianelli EA (2002) J Electroanal Chem 537:21
Ren X, Zelenay P, Thomas S, Davey J, Gottesfeld S (2000) J Power Sources 86:111
Heinzel A, Barragan VM (1999) J Power Sources 84:70
Narayanan SR, Frank H, Jeffries-Nakamura B, Smart M, Chun W, Halpert G, Kosek J, Cropley C (1995) In: Gottesfeld S, Halpert G, Landgrebe A (eds) Proton conducting membrane fuel cells I, PV 95-23. The Electrochemical Society Proceedings Series, Pennington, NJ, p 278
Lu GQ, Wang CY (2004) J Power Sources 134:33
Sun X, Li R, Villers D, Dodelet JP, Désilets S (2003) Chem Phys Lett 379:99
Qi Z, Kaufman A (2003) J Power Sources 113:37
Bittins-Cattaneo B, Iwasita T (1987) J Electroanal Chem 238:151
Frelink T, Visscher W, van Veen JAR (1994) Electrochim Acta 39:1871
Zhou Z, Wang S, Zhou W, Wang G, Jiang L, Li W, Song S, Liu J, Sun G, Xin Q (2003) Chem Commun 394
Franco EG, Oliveira-Neto A, Spinacé EV, Linardi M, Martz N, Mazurek M, Fuess H (2005) Mater Res 8:117
Bonnemann H, Brijoux W, Brinkmann R (1991) Angew Chem Int Ed Engl 30:1312
Pileni MP (1997) Langmir 13:3266
Xiong L, Manthiram A (2005) Electrochim Acta 50:2323
Wang X, Hsing I-M (2002) Electrochim Acta 47:2981
Zhou W, Zhou Z, Song S, Li W, Sun G, Tsiakaras P, Xin Q (2003) Appl Catal B Environ 46:273
Spinace EV, Oliveira-Neto A, Vasconcelos TRR, Linardi M (2004) J Power Sources 137:17
Oliveira-Neto A, Vasconcelos TRR, Da Silva RWRV, Linardi M, Spinace EV (2005) J Appl Electrochem 35:193
Spinace EV, Oliveira-Neto A, Vasconcelos TRR, Linardi M (2003) Brazilian Patent INPI-RJ, PI0304121-2
Scherrer P (1918) Nach Ges Wiss 26:98
Linardi M, Baldo WR, Bueno SAA, Saliba-Silva AM (2003) Método híbrido de spray e prensagem a quente, Patent submitted for deposit at INPI Brazil
Roth C, Martz N, Fuess H (2001) Phys Chem Chem Phys 3:315
Roth C, Goetz M, Fuess H (2001) J Appl Electrochem 31:793
Roth C, Martz N, Fuess H (2004) J Appl Electrochem 34:345
De Melo AG (2003) Personal Communication, IQ/USP São Paulo