Silver sulfide nanoparticles incorporated into graphene oxide: an efficient electrocatalyst for the oxygen reduction reaction

We report a facile one-step sonochemical synthesis of silver sulfide incorporated into reduced graphene oxide (Ag2S-RGO) for the oxygen reduction reaction (ORR). The Ag2S-RGO nanocomposite was characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy with mapping, and X-ray photoelectron spectroscopy (XPS). To evaluate the electrochemical performance, the surface of a glassy carbon electrode (GCE) was modified with the Ag2S-RGO nanocomposite for the ORR. The Ag2S-RGO nanocomposite-modified GCE showed higher electrocatalytic performance toward the ORR in terms of the electrocatalytic current density and the shift in overpotential when compared with those of RGO and a commercial Pt/C catalyst. The maximum current density was found to be 0.554 mA cm(-2) with an overpotential of - 0.39 V. Additionally, the proposed material showed excellent methanol tolerance, high stability, and good reproducibility and selectivity toward the reduction of O-2.