Novel catalysts, catalysts support and catalysts coated membrane methods

Abstract

This chapter introduces a new type of catalyst electrode for proton exchange membrane (PEM) fuel cells based on a nanostructured thin film catalyst support system. The nanostructured film consists of a single layer of a dense distribution of oriented crystalline whiskers of an organic pigment material. With areal number densities of 3–5 billion cm −2 and micrometer scale lengths, using dry processes, the whiskers are grown, coated uniformly with catalysts and transferred to the surface of a PEM to form an electrode. The physical and chemical properties of the nanostructured supports are reviewed first, followed by properties of the catalyst coatings and finally the electrode layer formation. Differences of these characteristics and properties from conventional carbon particle supported dispersed catalysts are widely made. Fuel cell performance examples and comparisons contrasting the mass and area cathode specific activities of the two types of catalyst electrode systems are demonstrated. The differences have implications for how membrane electrode assembly (MEA) are fabricated, ultimate catalyst loadings, system humidification requirements and durability.