Loading of Ag on Fe-Co-S/N-doped carbon nanocomposite to achieve improved electrocatalytic activity for oxygen evolution reaction

Oxygen evolution catalysts can effectively reduce the high overpotentials of oxidation evolution reaction. Here, we demonstrate that metallic Ag can improve the electrocatalytic performance of Fe-Co-S/N-doped carbon composites, which was prepared by a calcination route. Ag was loaded on the composite by a simple dipping method. With appropriate amount of Ag loading, the over potential to achieve current density of 10 mA cm−2 can make a decrease of 37 mV in 1 M KOH, while the Tafel slope almost doesn't change. It is demonstrated that loading of Ag not only improves the activity of catalytic site, but also cause a higher electrochemically-active surface area. The optimized OER catalyst was then covered on a hematite photoanode. The appropriate loading mass of the catalyst on hematite photoanode was investigated. It was found that the catalyst can improve the photocurrent density of 7 times enhancement at potential of 1.23 V vs RHE. This study demonstrates a surface decoration route to improve the catalytic activity, which would also be extended to other highly efficient catalysts for OER.