The most developed fuel cells are those working at low temperature using a polymeric electrolyte, PEMFC and DAFC, the latter making use of different alcohols directly as fuel. At present, the most effective fuel cell catalysts, both in cathode and anode, are highly dispersed platinum-based nanoparticles. These Pt nanoparticles are normally supported on carbon materials in order to increase the active surface area of Pt and improve the catalyst utilization. Among other factors, the performance of metal nanoparticles supported on carbon materials depends strongly on the properties of the support. For fuel cell applications, carbon supports should have several characteristics such as high surface area for dispersing catalytic metal particles, high electrical conductivity for providing electrical pathways, and mesoporous structure for the facile diffusion of reactants and by-products. Moreover, the interaction between the carbon support and the Pt plays an important role in the properties of the Pt/C catalyst. This interaction can be improved through the surface modification of the support in order to form proper functional groups and chemical links at the Pt/C interface. These functional groups can significantly affect the manufacture and performance of electrocatalysts, and they are responsible for both the acid-base and the redox properties of the carbon supports. Nowadays, among all kinds of carbon supports, carbon blacks are the most commonly used due to their high mesoporous distribution and their graphite characteristics. Vulcan XC-72(R) is the most frequently used in the preparation of commercial electrocatalysts because of its good compromise between electrical conductivity and high surface area. In this chapter, a detailed analysis about the properties of Vulcan XC-72R and the effect that different functionalization treatments have on them will be reported. Subsequently, the influence of the properties of the support on platinum supported catalysts will be established. The results of the use of these catalysts at the anode side of a PEM fuel cell will be presented in order to demonstrate the effective application of this carbon material in low temperature fuel cells and to establish the effect of the functionalization of the support on the fuel cell performance.
Study and application of Vulcan XC-72R in low temperature fuel cells
CALVILLO LAMANA, LAURA;
2011
Abstract
The most developed fuel cells are those working at low temperature using a polymeric electrolyte, PEMFC and DAFC, the latter making use of different alcohols directly as fuel. At present, the most effective fuel cell catalysts, both in cathode and anode, are highly dispersed platinum-based nanoparticles. These Pt nanoparticles are normally supported on carbon materials in order to increase the active surface area of Pt and improve the catalyst utilization. Among other factors, the performance of metal nanoparticles supported on carbon materials depends strongly on the properties of the support. For fuel cell applications, carbon supports should have several characteristics such as high surface area for dispersing catalytic metal particles, high electrical conductivity for providing electrical pathways, and mesoporous structure for the facile diffusion of reactants and by-products. Moreover, the interaction between the carbon support and the Pt plays an important role in the properties of the Pt/C catalyst. This interaction can be improved through the surface modification of the support in order to form proper functional groups and chemical links at the Pt/C interface. These functional groups can significantly affect the manufacture and performance of electrocatalysts, and they are responsible for both the acid-base and the redox properties of the carbon supports. Nowadays, among all kinds of carbon supports, carbon blacks are the most commonly used due to their high mesoporous distribution and their graphite characteristics. Vulcan XC-72(R) is the most frequently used in the preparation of commercial electrocatalysts because of its good compromise between electrical conductivity and high surface area. In this chapter, a detailed analysis about the properties of Vulcan XC-72R and the effect that different functionalization treatments have on them will be reported. Subsequently, the influence of the properties of the support on platinum supported catalysts will be established. The results of the use of these catalysts at the anode side of a PEM fuel cell will be presented in order to demonstrate the effective application of this carbon material in low temperature fuel cells and to establish the effect of the functionalization of the support on the fuel cell performance.
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