Hydrophobic catalyst layer for polymer electrolyte fuel cell and method of producing the same, and polymer electrolyte fuel cell and method of producing the same

Abstract

Provided is a hydrophobic catalyst layer for a polymer electrolyte fuel cell to which hydrophobicity is imparted so that the dissipation property of produced water is improved and which simultaneously has an increased effective surface area and an increased utilization ratio of a catalyst, and a method of producing the same. The catalyst layer for a polymer electrolyte fuel cell includes a catalyst obtained by reducing a platinum oxide, a hydrophobic agent, and a proton conductive electrolyte, wherein the hydrophobic agent is mainly composed of alkylsiloxane. An Si compound containing a hydrophobic substituent is brought into contact with a platinum oxide to subject the Si compound to hydrolysis and a polymerization reaction by the catalytic action of the platinum oxide, and then it is reduced, thereby obtaining a hydrophobic catalyst layer carrying an alkylsiloxane polymer.

Description

[0001] This application is a continuation of International Application No. PCT / JP2006 / 309356, filed Apr. 28, 2006, which claims the benefit of Japanese Patent Application No. 2005-132957, filed Apr. 28, 2005. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a hydrophobic catalyst layer for a polymer electrolyte fuel cell and a method of producing the same, and a polymer electrolyte fuel cell and a method of producing the same. [0004] 2. Description of the Related Art [0005] A polymer electrolyte fuel cell is expected to be an energy generating apparatus in the future because the cell has high energy conversion efficiency, and is clean and quiet. Investigation has been recently conducted into the application of the polymer electrolyte fuel cell to not only a power source for an automobile, a domestic generator, or the like but also a power source for, for example, a small-size electrical apparatus such as a portable phone, a noteboo...

AI Technical Summary

Benefits of technology

[0016] Accordingly, when conventional hydrophobic fine particles are used, the hydrophobicity of a catalyst layer improves, but there arises a problem in that part of the hydrophobic fine particles enter a gap between adjacent catalyst particles or between a catalyst and the electrolyte, so that a proton adsorption area of the surface of the catalyst, that is, an effective surface area reduces, and hence the utilization factor of the catalyst reduces.

[0041] In addition, the present invention can provide, at a low cost, a polymer electrolyte fuel cell having stable electricity generation property by using the above hydrophobic catalyst layer to which hydrophobicity is imparted.

Problems solved by technology

Accordingly, when conventional hydrophobic fine particles are used, the hydrophobicity of a catalyst layer improves, but there arises a problem in that part of the hydrophobic fine particles enter a gap between adjacent catalyst particles or between a catalyst and the electrolyte, so that a proton adsorption area of the surface of the catalyst, that is, an effective surface area reduces, and hence the utilization factor of the catalyst reduces.

As a result, there arises a problem in that local flooding occurs in the micro-gap to reduce the utilization factor of a catalyst.

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