Optimization of a Fe-N-C electrocatalyst supported on ordered mesoporous carbon functionalized with polypyrrole for oxygen reduction reaction

In this work a Fe-N-C non-noble metal electrocatalyst for oxygen reduction reaction (ORR) is optimized. The catalyst is synthesized using mesoporous carbon (MPC) as C source, polypyrrole (PPY) as N source and Fe(II) acetate. In the first part, the influence of the addition of a surfactant, and of a heat treatment of the MPC-PPY support before the impregnation with Fe(II) ions is investigated. In the second part, the best catalyst obtained in the first part is used as support, and the influence of a second pyrolysis treatment performed with or without further impregnation with Fe(II) is investigated. Materials are characterized by SEM-EDX, BET-porosimetry, XPS and TEM analyses. The electroactivity towards ORR was tested with a rotating disk electrode in acidic and alkaline conditions. An evident increase of electroactivity after the second heat treatment is found, as well as a concomitant increase of surface area and micropore content.