Effect of nitrogen doping method on the activity of Fe-N-C catalysts based on carbon xerogels for fuel cells

Abstract

The development of active and inexpensive non-precious metal catalysts is a necessary and essential requirement to replace currently used Pt-based catalysts, in order to reduce the cost of polymer electrolyte fuel cells(PEFC). [1] Catalysts based on the Fe-N-C structure develop high electroactivity towards the oxygen reduction reaction (ORR), the limiting reactionin fuel cells. To increase the catalysts activity, Fe must be dispersedin acarbon material with a high surfacearea.In this context, carbon xerogels are excellent candidates, as their main properties can be easily tailored: porosity, electrical conductivity and surface chemistry. [2] The meso/macroporosity of carbon xerogels can be designed by modifying the conditions of the synthesis process, while microporosity can be generated by subsequent carbonization/activation treatments [3].In the present work, on the basis of carbon xerogels with an optimal ratio of micro/meso/macroporosity, we investigate the effect of two different methods of nitrogen-doping in the catalytic activity of Fe-N-C catalysts. Catalysts are evaluated both in half-cell and single-cell configurations and their activity is correlated to their physical-chemical features.