Construction of Highly Active Metal‐Containing Nanoparticles and FeCo‐N₄ Composite Sites for the Acidic Oxygen Reduction Reaction

Metal‐containing nanoparticles (M‐NPs) in metal/nitrogen‐doped carbon (M‐N‐C) catalysts have been considered hostile to the acidic oxygen reduction reaction (ORR). The relation between M‐NPs and the active sites of metal coordinated with nitrogen (MN x ) is hard to establish in acid medium owing to the poor stability of M‐NPs. Herein, we develop a strategy to successfully construct a new FeCo‐N‐C catalyst containing highly active M‐NPs and MN 4 composite sites (M/FeCo‐SAs‐N‐C). Enhanced catalytic activity and stability of M/FeCo‐SAs‐N‐C is shown experimentally. Calculations reveal that there is a strong interaction between M‐NPs and FeN 4 sites, which can favor ORR by activating the O−O bond, thus facilitating a direct 4 e − process. Those findings firstly shed light on the highly active M‐NPs and FeN 4 composite sites for catalyzing acid oxygen reduction reaction, and the relevant reaction mechanism is suggested.