Silver/Nitrogen-Doped Graphene Interaction and Its Effect on Electrocatalytic Oxygen Reduction

Three types of silver/reduced graphene oxide (Ag/rGO) nanocomposites (one doped with nitrogen and another two without) are synthesized to investigate their atomic structures and the oxygen reduction reaction (ORR) performance with them as the electrocatalysts. For the first time, the bonding interaction between Ag and N in N doped rGO (N-rGO) is confirmed by both high resolution X-ray photoelectron spectroscopy (XPS) and surface enhanced Raman spectroscopy (SERS). The Ag/N-rGO shows excellent ORR performance, including very high onset potential and current density, which outperforms those Ag/rGOs without N doping. Detailed electrochemical analysis shows that the ORR mechanism on Ag/N-rGO is different from both Ag and N-rGO, and its excellent performance is caused by the Ag–N bonding which alters the electronic structure of N-rGO.