▎ 摘　　要

The PtCo alloyed nanoparticles (NPs) supported on thiolated graphene (tG) has been electrochemically reduced (denoted as ER/PtCo-tG) by means of a facile and rapid protocol for improving electrochemical oxygen reduction reaction (ORR). The as prepared binary alloyed catalyst has been characterized by morphological and structural analysis using transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The TEM and XRD analysis reveal that the PtCo NPs have found in crystalline structure and Co presents with the oxidized form in catalyst. The electrocatalytic activity towards ORR has been verified using both cyclic voltammetry and hydrodynamic voltammetry. The ER/PtCo-tG catalyst exhibits high electrocatalytic activity towards ORR and reaction proceeds via nearly four-electron transfer pathway into H2O in 0.1 M KOH alkaline solution. The as prepared catalyst has shown 20% and 75% higher current density and mass activity, respectively, than that of 20 wt% Pt/C. The excellent catalytic activity has mainly ascribed to the smaller size and well dispersed PtCo NPs which are covalently grafted with the assistance of S atom onto graphene, comparatively better alloyed formation of Co with Pt and probable influence from Co(OH)(2).