Carbon incorporated FeN/C electrocatalyst for oxygen reduction enhancement in direct methanol fuel cells: X-ray absorption approach to local structures

Highlights: → Nonprecious iron nitride catalysts demonstrate an excellent anti-methanol crossover performance; it could be benefic for the applications in direct methanol fuel cells (DMFCs). → H2O2 is poorly yielded in the electrochemical test. It could be helpful for a proton exchange membrane, since H2O2 would etch the membrane. → Tafel plot and rotating ring disk electrode (RRDE) both give that electron transfer numbers are close to 4 in oxygen reduction reaction (ORR), indicating the major product as H2O. → Fe-C contributes to the FeCN/C catalyst by using EXAFS analysis. FeCN nanoparticles would disperse on C supports and may give ORR activity. - Abstract: The C-containing iron nitride electrocatalyst is fabricated by chelating N-containing species and Fe2+ with a carbon support under heat treatment in an NH3 atmosphere, which induces the oxygen reduction reaction activity. This is the first demonstration of forming FexC species on iron nitride materials. The correlation between the electrochemical properties and structures are aided to elucidate their features under investigation by using X-ray absorption spectroscopy. A rotating ring disk electrode test is conducted in sulfuric acid solution and the results reveal the low H2O2 yield and approximately 4e- transfer process of the carbon-containing FeN/C electrocatalyst.