Development of Novel Materials for Proton Exchange Membrane Fuel Cells
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0948-B09-05
Development of Novel Materials for Proton Exchange Membrane Fuel Cells Burak Birkan, Albert Levi, Cenk G¸meci, Mehmet Ali G¸lg¸n, and Yusuf Ziya Mencelolu Material Science and Engineering Department, Sabanci University, Orhanli, Tuzla, Istanbul, 34956, Turkey
ABSTRACT The most known utilization of catalysts is the use of metal nanoparticles on the electrode of a Proton Exchange Membrane Fuel Cell on which the electrode consists of catalyst, either Pt or Pd on a carbon support. In this research porous polyacrylonitrile (PAN) based carbon nanofibers comprising nanosized metal particles are produced using electrospinning technique. By the optimization of polymer chemistry, electrospinning variables and carbonization procedures the effective metal size is reduced up to 5 nm. It is still possible to enhance the catalytic performance by decreasing the metal concentration and/or enable using less catalytic material for equivalent catalytic performance which can lead to cost savings, amongst other advantages. INTRODUCTION Nanomaterials draw much attention nowadays because the diversity of their use in many fields from catalysis to photonics and from electrochemical sensors to filters. A wide variety of nanomaterials, especially nanoparticles with different properties have found broad application in many kinds of analytical methods. Due to their small size (generally 1 -100 nm) nanoparticles exhibit unique chemical, physical and electronic properties that are different from those of bulk materials with a high surface area to volume ratio. The most known utilization of catalysts is the use of metal nanoparticles on the electrode of a Proton Exchange Membrane Fuel Cell on which the electrode consists of a catalyst, either Pt or Pd on a carbon support. The catalytic behavior of a precious metal supported on a given material is determined mainly by the microscopic distribution of the metal over the support particles, the metal oxidation state and sensitivity to the fuel quality. Because such catalytic materials are expensive, the plan is to use less catalytic material but to maintain the catalytic activity. Methods for obtaining in-situ of metal nanoparticles are known in the literature. Despite the production of nanoparticle metal coated nanofibers is achieved by additional steps like electro deposition [1], vacuum deposition [2], selective reducing [3] etc. when synthesizing metalized high surface area nanofibers, the dimensions of these nanofibers as well as the dimensions of the metal particles on them are restricted by the use of the metal/reducer couple, the metal weight percentage on the polymer solution and the heat treatment cycle. Thus, there is a need for metal nanoparticles supported in carbon fiber with a smaller fiber diameter and for a method to produce them in an efficient and cost effective way. In this research acrylonitrile based porous copolymer carbon fibers comprising nanosized metal particles are produced using electrospinning technique. Acrylonitrile is copolymerized with 2-acrylamido-2-met
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