Chapter 26 - Nanoscale, Catalyst Support Materials for Proton-Exchange Membrane Fuel Cells

Abstract

Over the past few decades, proton-exchange membrane (PEM) fuel cells are promising candidates for various applications, ranging from mobile phones to automobiles, due to their high power output, moderate operating temperature, and quick start-up. Presently, the commercial deployment of such devices is hindered by the high price and inadequate durability of the platinum catalyst electrodes. The widely used carbon supported platinum catalysts are very fine particles, a conventional coating of which can decrease the surface area and thereby can adversely affect the triple phase boundary (TPB) of the catalyst layer by decreasing the surface diffusion. Therefore, an effective catalyst layer with maximum surface diffusion with enhanced porosity has to be developed in order to extend the TPB in PEM fuel cell electrode assembly. The “triple phase boundaries” are confined spatial active sites where, the electrolyte, gas, and electrically connected catalyst regions are in contact, at which hydrogen oxidation reaction and the oxygen reduction reaction occur. Therefore, understanding and controlling the degree of TPB in fuel cell catalyst layer provides excellent opportunities for performance enhancement. This book chapter provides an overview of recent advances in state-of-art nanostructured support materials for electrocatalysts. The noncarbon-based support materials, such as titanium oxides, titanium di borides, titanium nitrides, tungsten oxides, tungsten carbides, tin oxides, and carbon-based support materials, such as Vulcan XC-72, carbon gels, activated carbon fibers, carbon nanotubes, carbon nanohorns, proposed for proton exchange membrane fuel cells have been discussed.