Chapter 7: New Generation of Catalyst Layers for PEMFCs Based on Carbon Aerogel Supported Pt Catalyst (CASPC)
The mass production of PEMFC power generators requires a price reduction and, thus, a decrease in the amount of noble metals present in the cathode and anode catalyst layers. Automotive, residential, military, and small scale applications require PEMFC stacks with a Pt-specific power density of at least 0.2 gPt/kW at cell voltages of about 0.65 V. However, existing PEMFC performance corresponds to approximately 0.85 1.1 g Pt/kW. Thus, at least a five-fold reduction of the amount of noble metal in the PEMFC catalyst layer is required for large scale manufacturing .
Developed over the past ten years, carbon aerogels are porous materials having a network structure of interconnected nanosized primary particles and in addition to a large surface area  include well-developed and controlled mesoporosity. Their tunable properties, such as surface area, pore volume, and pore size distribution, determined by the synthesis and processing conditions, allow for a wide spectrum of materials with unique properties and broad area of application, such as electrochemistry, fuel cells, catalysis, optics, and microelectronics , , , .
The carbon aerogel supported Pt catalyst (CASPC) structures differ significantly from those of presently available commercial catalysts produced by such companies as Tanaka, E-TEK, and Alfa Aesar. The carbon aerogel synthesized under supercritical conditions in the presence of CO 2, has a narrow pore size distribution and the size of the single pore that can be easily adjusted through...