Synthesis of Fe–N–C Single-Atom Catalysts with a Facile Salt-Templated Strategy for Efficient and Stable Oxygen Reduction Reaction

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The active Fe–N–C single-atom catalysts (Fe–N–C SACs) are considered the best alternatives to platinum-containing electrocatalysts for the application of metal–air batteries and fuel cells. However, several issues regarding facile preparation and stability still need to be resolved. This work proposes a facile molten NaCl-templated strategy to synthesize Fe–N–C SACs with Fe 2 O 3 as the Fe source. The introduction of molten NaCl during pyrolysis generates abundant micropores, whose volume reaches a 3-fold enhancement over the NaCl-free sample. The specific surface area increases to 1617.8 m 2 g –1, providing more accessible sites to host Fe atoms and improving mass transfer efficiency. The optimal Fe–N–C SACs demonstrate outstanding oxygen reduction reaction (ORR) activity with an exceedingly high half-wave potential of 0.91 V in alkaline media. They also overcome the dependence of activity and stability on the pH of the electrolyte. This work proposes an innovative approach to enable the systematic development of high-performance ORR catalysts, demonstrating the feasibility of employing salt templating for fabricating atomically dispersed catalysts.