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

Abstract

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.

Freestanding 1D Hierarchical Porous Fe‐N‐Doped Carbon Nanofibers as Efficient Oxygen Reduction Catalysts for Zn–Air Batteries

“…Especially, the organic units from Zn, Fe‐ZIF cloud transformed into N‐doped carbon materials . In Figure c, the Fe 2p spectrum was ascribed into six peaks: in the lower‐energy (2p 3/2 ) region, the energy peaks at 710.9 and 714.4 eV correspond to Fe 2+ and Fe 3+ species; in the higher‐energy (2p 1/2 ) region, the energy peaks at 723.6 and 726.1 eV are ascribed to Fe 2+ and Fe 3+ ; the satellite peak at 718.5 eV indicates the co‐existence of Fe 2+ and Fe 3+ ; finally, the peak at 708 eV is assigned to the zero‐valence metallic or iron carbide; the weak intensity is attributed to the low density of aggregated metallic Fe and an encapsulation of the Fe–N x active sites by the carbon matrix . Inductively coupled plasma emission spectroscopy (ICP‐AES) was used to measure the content of iron.…”

Pearl Necklace Fibrous Carbon Sharing Fe–N/Fe–P Dual Active Sites as Efficient Oxygen Reduction Catalyst in Broad Media and for Liquid/Solid‐State Rechargeable Zn–Air Battery

“…A satellite peak at 718.7 eV also indicated the coexistence of Fe (II) and Fe (III) species. It was noteworthy that the peak around 708 eV attributed to zero‐valence metallic or iron carbide; however, its weak intensity hinted of negligible existence for aggregated metallic Fe while an evolution of Fe–N x active site by the carbon matrix . In addition, the high‐resolution P 2p spectrum (Figure d) was fitted into a major peak of P–O and a weak signal for Fe–P .…”

Transition Metal Carbide Complex Architectures for Energy‐Related Applications

“…When used as the catalyst for HER, the molybdenum carbide (MoSoy) nanoparticles afford a small overpotential of 177 mV at the current density of 10 mA cm −2 (Figure c). Besides, some other types of carbon/organic species and metals were also successfully used to fabricate the energy‐related TMC nanoparticles by this method …”