Low‐Work‐Function Silver Activating N‐doped Graphene as Efficient Oxygen Reduction Catalysts in Acidic Medium

Non‐platinum graphene‐based electrocatalysts are vital for low‐cost energy conversion by hydrogen fuel cell. However, high oxygen reduction reaction (ORR) overpotentials limit their efficiency and stability. Here, we propose a strategy to increase graphene Fermi level by graphene encapsulating a metal with lower work function than graphene, aiming to enhance the ORR activity of graphene‐based materials. As an example, Ag nanoparticles (function work, 4.2 eV) are embedded into N‐doped graphene (function work, 4.5 eV) (Ag@NG). The Ag@NG exhibits the ORR onset potential of 0.804 V and excellent stability over 10000 electrochemical cycles in acidic electrolyte. Spectroscopic analysis confirms Ag−N coordination bond as an efficient electron transfer route significantly benefiting upshift of graphene Fermi level that enhances the ORR activity and stability. Level up: The authors embedded the Ag, a low‐work‐function metal, as a strong electron donor, into N‐doped graphene. As a result of Ag−N interaction, the accelerated charge transfer at Ag@NG‐electrolyte interface would induce the upshift of Fermi level of graphene, which effectively reduces the barrier for electron injection from graphene into the oxygen‐containing species and improves ORR performance.