Non precious metal catalysts for O₂ reduction in pemfc applications

There is a need for a non-precious metal oxygen reduction catalyst in Polymer Electrolyte Membrane Fuel Cells (PEMFC). In this work two plasma reactors were optimized to treat carbon black powders, which are used as the support for these catalysts. The aim of this treatment is to obtain nitrogen-bearing functionalities on the carbonaceous surface that will be able to coordinate iron ions in order to catalyze the oxygen reduction reaction (ORR). Different carbon supports as well as several conditions during the plasma treatments have been evaluated. The final materials were characterized by means of XPS and pH measurements. After loading the plasma treated carbon with iron, followed by a pyrolysis treatment, the material was tested for its catalytic activity using a Rotating Disk Electrode (RDE). The results show that plasma modification is effective in producing non-precious metal catalysts on selected carbon black powders like carbon N134, but it is detrimental for a carbon black like Vulcan.