Biomass Derived N-Doped Porous Carbon Supported Single Fe Atoms as Superior Electrocatalysts for Oxygen Reduction

Abstract

Exploring sustainable and high-performance electrocatalysts for the oxygen reduction reaction (ORR) is the crucial issue for the large-scale application of fuel cell technology. A new strategy is demonstrated to utilize the biomass resource for the synthesis of N-doped hierarchically porous carbon supported single-atomic Fe (SA-Fe/NHPC) electrocatalyst toward the ORR. Based on the confinement effect of porous carbon and high-coordination natural iron source, SA-Fe/NHPC, derived from the hemin-adsorbed bio-porphyra-carbon by rapid heat-treatment up to 800 °C, presents the atomic dispersion of Fe atoms in the N-doped porous carbon. Compared with the molecular hemin and nanoparticle Fe samples, the as-prepared SA-Fe/NHPC exhibits a superior catalytic activity (E_1/2 = 0.87 V and J_k = 4.1 mA cm^-2 , at 0.88 V), remarkable catalytic stability (≈1 mV negative shift of E_1/2 , after 3000 potential cycles), and outstanding methanol-tolerance, even much better than the state-of-the-art Pt/C catalyst. The sustainable and effective strategy for utilizing biomass to achieve high-performance single-atom catalysts can also provide an opportunity for other catalytic applications in the atomic scale.