Zeolites and Molecular Sieves in Fuel Cell Applications

Abstract

IntroductionZeolites and molecular sieves belong to an important class of natural and synthetic porous materials [1] that find important applications in many industrial processes including chemical separation and purification, chemical synthesis and fuel conversion, and pollution treatment and abatement [2][3][4]. The discovery of MCM-41 in 1992 [5, 6] has attracted research in the synthesis and applications of large pore molecular sieves including ordered mesoporous materials. The mesoporous materials display a greater range of pore sizes and compositions than typical zeolites and molecular sieves, and researches show that they are excellent catalyst, adsorbent, and membrane materials that have potential applications not only in traditional chemical processes but also in microelectronics, sensors, and agriculture [7-10].Fuel cell promises clean and efficient energy generation for stationary, mobile, and portable applications [11]. Striving for enhanced performance, zeolites and mesoporous materials are increasingly used in fuel cells. They were used to increase proton transport, decrease fuel crossover, and improve water management in the electrolyte membrane. They serve as electrode and electrocatalyst in the fuel cell and are also employed in fuel conversion, reforming, and storage. There are a number of excellent reviews on fuel cell electrolyte membranes [12][13][14][15][16][17] and electrode materials [18,19] in the literature, but none includes the recent uses of zeolites and molecular sieves. This chapter reviews the contributions of zeolites and molecular sieves in fuel cell research and is divided into three sections: (i) zeolites in electrolyte membrane, (ii) zeolites in fuel cell electrocatalysis, and (iii) zeolites in fuel processing for fuel cells. Zeolites in Electrolyte MembraneThe electrolyte membrane in a fuel cell separates the anode and cathode reactants and mediates the electrochemical reactions at the electrodes by rapid and selective