Nitrogen and iron doped carbon aerogels as Fe-N-C catalyst

Abstract

The work is focused on the synthesis of nitrogen and iron doped carbon aerogels as Fe-N-C catalysts for fuel cells. A fuel cell uses the chemical energy of hydrogen or other fuels to cleanly and efficiently produce electricity. In polymer electrolyte membrane fuel cells, platinum is used as a catalyst to promote the sluggish oxygen reduction reaction. A suitable alternative to critical raw materials is ironnitrogen complexes embedded in a porous, carbonaceous structure. Carbon aerogels have a great potential to be used as a carbon host for this purpose. Carbon aerogels are three-dimensional, open porous solid materials produced via carbonization of organic aerogels based on e.g. resorcinol-formaldehyde polymers. Carbon aerogels exhibit unique properties such as well-controlled pore size distribution, high porosity, large specific surface area, high electrical conductivity and low envelope density. These characteristics make them promising materials for applications in adsorption, catalysis, supercapacitors, fuel cells or batteries. For the application as a catalyst, the carbon matrix has to be modified in order to introduce active sites into the carbon structure. Therefore, the carbon material is treated with different synthesis steps to introduce nitrogen and iron into the carbon structure. Prior nitrogen doping of the carbon material, oxygen doping was identified as a crucial step. The oxidized carbon material can then be mixed with nitrogen and iron precursors and thermally treated to get Fe-N-C materials. Within this poster presentation, recent results from different synthesis techniques as well as results from physical and chemical characterization of the doped carbon aerogels will be presented. For this purpose, the microstructure of the doped carbon aerogels is investigated with physisorption measurements and scanning electron microscopy. In addition, measurement of the electrical conductivity using for example the four-pin method and Raman spectroscopy are carried out.