N,P Co‐Coordinated Manganese Atoms in Mesoporous Carbon for Electrochemical Oxygen Reduction

The increasing interest in fuel cell technology encourages the development of efficient and low‐cost electrocatalysts to replace the Pt based materials for catalyzing the cathodic oxygen reduction reaction (ORR). In the present work, a nitrogen and phosphorus co‐coordinated manganese atom embedded mesoporous carbon composite (MnNPC‐900) is successfully prepared via a polymerization of o‐phenylenediamine followed by calcination at 900 °C. The MnNPC‐900 composite shows a high ORR activity in alkaline media, offering an onset potential of 0.97 V, and a half‐wave potential of 0.84 V (both vs reversible hydrogen electrode) with a loading of 0.4 mg cm^?2. This performance not only exceeds its phosphorus‐free counterpart (MnNC‐900), but also is comparable to the Pt/C catalyst under identical measuring conditions. The significantly enhanced ORR performance of MnNPC‐900 can be ascribed to: i) the introduction of phosphorus assists the generation of mesopores during the pyrolysis and endows the MnNPC‐900 composite with large surface area and pore volume, thus facilitating the mass transfer process and increases the number of exposed active sites. ii) The formation of N,P co‐coordinated atomic‐scale Mn sites (MnN_xP_y), which modifies the electronic configuration of the Mn atoms and thereby boosts the ORR catalytic activity.