Breton Electrochemical Division


FeSn/Graphene can be used as electrocatalyst for the Oxygen Reduction Reaction (ORR) that takes place in an alkaline environment of Alkaline Electrolyte Membrane (AEMFC); accordingly, AEMFCs can adopt “Pt-free” ORR ECs and still achieve a high performance level. This new “Pt-free” electrocatalyst comprises a graphene support “core”, which is covered by a carbon nitride “shell” coordinating the ORR active sites.
The proposed material reaps the benefits offered by graphene, including: (i) a high electrical conductivity, minimizing the ohmic losses; and (ii) a low microporosity, to facilitate the mass transport of reactants and products.
The carbon nitride “shell” coordinates the bimetallic active sites, which include: (i) a 3d-“active metal” (i.e., Fe, Co, Ni), which bestows most of the ORR performance; and (ii) an oxophilic “co-catalyst” (Sn), which stabilizes the “active metal” and improves the ORR kinetics.
The ORR performance are clarified by means of cyclic voltammetry with the thin-film rotating ring-disk electrode (CV-TF-RRDE) method. The results show the potential of this family of “Pt-free”, “core-shell” graphene-supported electrocatalysts for application at the cathode of AEMFCs. In particular, CV-TF-RRDE measurements in an alkaline environment demonstrated that the best material exhibits an ORR overpotential ca.70 mV higher with respect to a 10 wt.% Pt/C reference (for more information see: Negro et al. Towards Pt-free Anion-Exchange Membrane Fuel Cells: Fe-Sn Carbon Nitride-Graphene Core-Shell Electrocatalysts for the Oxygen Reduction Reaction, Chem. Mater., DOI: 10.1021/acs.chemmater.7b05323).