chemical engineering research and design 88 (2010) 496–500 Contents lists available at ScienceDirect Chemical Engineering Research and Design journal homepage: www.elsevier.com/locate/cherd Nafion/Analcime and Nafion/Faujasite composite membranes for polymer electrolyte membrane fuel cells Paisan Kongkachuichay ∗ , Siraprapa Pimprom Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok, 10900, Thailand abstract The Nafion/zeolite composite membranes were synthesized for polymer electrolyte fuel cells (PEMFCs) by adding zeolite in the matrix of Nafion polymer. Two kinds of zeolites, Analcime and Faujasite, having different Si/Al ratio were used. The physico-chemical properties of the composite membranes such as water uptake, ion-exchange capacity, hydrogen permeability, and proton conductivity were determined. The fabricated composite membranes showed the significant improvement of all tested properties compared to that of pure Nafion membrane. The maximum proton conductivity of 0.4373 S cm -1 was obtained from Nafion/Analcime (15%) at 80 ◦ C which was 6.8 times of pure Nafion (0.0642 S cm -1 at 80 ◦ C). Conclusively, Analcime exhibited higher improvement than Faujasite. © 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Keywords: Composite membrane; Fuel cell; Nafion; Zeolites 1. Introduction Polymer electrolyte membrane fuel cell (PEMFC) is one of the most attractive power sources for a variety of applications. It has high efficiency and is environment-friendly (Alberti et al., 2001; Adjemian et al., 2002; Costamagna et al., 2002; Havenga et al., 2003; Hogarth et al., 2005). PEMFC operation requires an electrolyte membrane to separate the chemical reaction at anode from cathode both chemically and electrically. The effective membrane must have good chemical, physical and thermal stabilities as well as high proton conductivity (Smitha et al., 2005). The most widely used electrolyte membrane is Nafion ® , a perfluorinated sulfonated polymer. However, one limitation of the current PEMFC is the trace of CO in the hydro- gen supply, which can poison the Pt anode. The CO poisoning effect can be retarded by operating at an alleviated tempera- ture (Alberti et al., 2001; Adjemian et al., 2002; Costamagna et al., 2002; Saccà et al., 2005). The reaction rates at the anode and cathode are increased at higher temperature. However, the proton conductivity of Nafion membrane strongly depends on water content in the membrane. Hence, Nafion membrane cannot operate at too high temperature because it will loss too much water, resulting in the decrease in proton conductivity. Thus, the concept of operating a cell at higher temperature is keeping the membrane hydrated to maintain its proton con- ∗ Corresponding author. Tel.: +66 25792083; fax: +66 25614621. E-mail address: fengpsk@ku.ac.th (P. Kongkachuichay). Received 27 March 2009; Received in revised form 12 August 2009; Accepted 28 August 2009 ductivity (Yang et al., 2001; Sasikumar et al., 2004; Shao et al., 2004; Hogarth et al., 2005; Saccà et al., 2005; Smitha et al., 2005). Several researchers have tried to prevent the loss of water from the ionic pores of the Nafion by modifying the mem- brane. One of the approaches is incorporating hydrophilic metal oxide particles (e.g., SiO 2 , ZrO 2 , TiO 2 ) to enhance the water retention property (Yang et al., 2001; Shao et al., 2004; Jalani and Datta, 2005; Kim et al., 2004; Antonucci et al., 2008). Other hybrid membranes have been also fabricated by adding phosphotungstic acid (Shao et al., 2004), cesium sulfate and zirconium phosphate (Yang et al., 2001 and Costamagna et al., 2002), and mordenite (Kwak et al., 2003). Zeolites are microporous aluminosilicate minerals. They have three-dimensional structures arising from the coordina- tion of silicate ([SiO 4 ] 4- ) and aluminate ([AlO 4 ] 5- ) tetrahedral linked by all corners (Dyer, 1988). Because of the difference charge between [SiO 4 ] 4- and [AlO 4 ] 5- , when both tetrahe- dral link together it will create a negative charge inside the secondary building unit. Subsequently, this charge will be neu- tralized by attracting metal ion (e.g., Na + ,K + ). Accordingly, zeolites are widely used as ion-exchangers and can hydrate with high amount of water (Breck, 1974). In addition, their properties are mostly depended on the Si/Al ratio of their structures. 0263-8762/$ – see front matter © 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.cherd.2009.08.017