A Versatile Iron–Tannin‐Framework Ink Coating Strategy to Fabricate Biomass‐Derived Iron Carbide/Fe‐N‐Carbon Catalysts for Efficient Oxygen Reduction

The conversion of biomass into valuable carbon composites as efficient non-precious metal oxygen-reduction electrocatalysts is attractive for the development of commercially viable polymer electrolyte membrane fuel-cell technology. Herein, a versatile iron-tannin-framework ink coating strategy is developed to fabricate cellulose-derived Fe3 C/Fe-N-C catalysts using commercial filter paper, tissue, or cotton as a carbon source, an iron-tannin framework as an iron source, and dicyandiamide as a nitrogen source. The oxygen reduction performance of the resultant Fe3C/Fe-N-C catalysts shows a high onset potential (i.e. 0.98 V vs the reversible hydrogen electrode (RHE)), and large kinetic current density normalized to both geometric electrode area and mass of catalysts (6.4 mA cm(-2) and 32 mA mg(-1) at 0.80 V vs RHE) in alkaline condition. This method can even be used to prepare efficient catalysts using waste carbon sources, such as used polyurethane foam.