Fe3N decorated S/N doped carbon derived from a coordinated polymer as a bifunctional electrocatalyst for oxygen reduction and catecholamines oxidation

A novel iron-coordinated conducting polymer is synthesized, followed by the preparation of Fe3N nanoparticle-embedded sulfur and nitrogen-doped carbon (Fe3N/SNC) nanostructures via a one-step polymer pyrolysis strategy, which can exceptionally catalyze the oxygen reduction reaction (ORR) in both alkaline and acidic media, and the oxidation of catecholamines. To synthesize the metal coordinated polymer, FeCl3 is used as an oxidant and metal source for the polymerization of 3′,4′-diamino-terthiophene (DAT) to form poly-FeDAT. It is subsequently pyrolyzed at 900 °C to attain the Fe3N/SNC catalyst. The Fe3N/SNC electrocatalyst exhibit a more positive onset (0.985 V vs RHE), half-wave potentials (0.848 V), a higher limiting current density (5.47 mAcm−2), alcohol resistance and durability than the benchmark Pt/C in 0.1 M KOH, and it is comparable to Pt/C in 0.1 M HClO4. It also displays exceptional performance for the catalytic oxidation of catecholamines and AP, which results in simultaneous detection of DA and AP in trace amounts (the detection limits were 110 nM and 270 nM (S/N = 3) for each species, respectively). The unique catalytic activity is ascribable to the presence of pyridinic-N, graphitic-N, and Fe–N along with thiophene-S in the carbon, resulting in catalytically enhanced electron transfer from Fe3N to N, S doped carbon.