Honeycomb-like Carbon-supported Fe Single Atom Catalyst: Preparation and Electrocatalytic Performance in Oxygen Reduction Reaction

Single atom catalysts (SACs) have emerged as an attractive concept for promoting heterogeneous reactions due to the unique properties, such as high activity and nearly 100% atom utilization. However, the synthesis of SACs remains a challenge due to the sintering of metal atoms at high temperature. In this study, Fe single atom on N doped porous carbon (Fe SA-NC) catalyst was obtained by ultrastrong polarity of molten salt (MS). Fe SA-NC shows honeycomb-like porous morphology and possesses a high specific surface area of 2072 m(2).g(-1). The content of Fe element in Fe SA-NC is 0.57wt%. The isolated Fe atoms are observed by AC HAADF-STEM, and the X-ray absorption fine structure (XAFS) analysis confirms that Fe atoms disperse in the form of Fe-N-4 on the carbon substrate. Fe SA-NC shows 0.85 V half-wave potential and 5.79 mA.cm(-2) maximum current density for ORR in 0.1 mol/L KOH solution. Fe SA-NC displays high selectivity for ORR four electron pathway (H2O2 yield<2%, electron transfer number is 3.9), outstanding stability, and good methanol tolerance.