Silver Clusters with Adatoms as a Catalyst for the Oxygen Reduction Reaction

Developing highly active and low-cost catalysts for the oxygen reduction reaction (ORR) is critical for renewable energy devices such as metal–air cells and fuel cells. In this work, we report an active ORR catalyst, Ag clusters with adatoms, which can be facilely produced by a pulse electrolysis method. The silver adatom on the silver cluster can reduce the coordination number, upshift the Ag d-band center, lower the ORR reaction barrier, and eventually transform the inactive Ag into a highly active catalyst. As a result, the catalyst exhibits high activity and stability, which are superior to ever-reported silver-based catalysts and even the commercial Pt/C catalyst.