Non-noble Fe-NX electrocatalysts supported on the reduced graphene oxide for oxygen reduction reaction

In this paper, the reduced graphene oxide (rGO) is synthesized from graphite oxide (GO) via microwave exfoliation method, and used to support non-noble metal Fe-NX based electrocatalysts (Fe-NX/rGO) for the oxygen reduction reaction (ORR). Tripyridyl triazine (TPTZ) is used as a ligand for Fe-NX catalyst preparation. The obtained catalyst presents a high content of pyridinic (N1) and pyrrolic (N2) nitrogen types on the catalyst surface (40.0% and 52.3% atomic concentrations, respectively) with Fe atomic content of 0.7%. A catalyst loading of 0.5 mg cm−2 with a ionomer-to-carbon (ITC) mass ratio of 0.2 deposited on the glassy carbon electrode allows the highest ORR activity with the specific current of −0.35 mA mg−1 at a cell voltage of 0.8 V (vs. RHE). The overall electron transfer number obtained is of 3.98. Stability tests in acidic solution for this catalyst are also performed.