Influence of carbon support structure on cathode catalysts durability

Abstract

The most important barrier of the common fuel cells application is the lack of effective and durable electrocatalysis for the oxygen reduction reaction. This article presents the results obtained for platinum nanoparticles deposited on carbon black with structure modified by heat treatment at high temperatures (up to 3000 °C). The TEM, XRD, Raman, EELS and XPS spectroscopy was used to evaluate how the change in the support structure affects the structure of the deposited catalytic particles and the durability of the produced catalytic system. The influence of the changes of the carbon support structure caused by annealing temperature on the durability of the Pt/CB system is complex. Initially, for medium temperatures, heating removes amorphous carbon and ionic impurities, reduces microporosity, increases graphitization, and sp2 carbon atom content. The main impact is exerted by the reduction of the concentration of functional groups and structure defects, as these changes lead to deterioration of nanoparticle dispersion and stability. For higher temperatures further increase in graphitization enables the formation of a strong interaction between Pt and C and sufficiently increases the corrosion resistance of the support, which altogether leads to an improvement in the durability of the entire system.