A convenient method based on photocatalytic reduction was used to prepare graphene-supported Pd, Fe, and bimetallic Pd-Fe nanoparticle (NP) catalysts under mild conditions. The obtained catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Their potential application to the electrocatalytic degradation of chlorinated phenols (CPs) was investigated by cyclic voltammetry (CV) and chronoamperometry. The graphene-supported bimetallic Pd-Fe NP catalyst (Pd0.5Fe0.5/graphene) exhibited the optimal surface performance and contained highly abundant and widespread Pd-Fe NPs of approximately 6.75 +/- 0.05 nm in size. It exhibited higher electrocatalytic activity for dechlorination of CPs attributed to its higher hydrogen adsorption peak current of 0.117 mA than that of the Pd/graphene catalyst, with a 1% weight ratio of Pd (Pd-1.0/graphene catalyst), and the Fe/graphene catalyst, with a 1% weight ratio of Fe (Fe-1.0/graphene catalyst). The highest reductive peak current (0.038 mA) was obtained at -0.347 V when using the Pd0.5Fe0.5/graphene catalyst, indicating that the Pd0.5Fe0.5/graphene catalyst has the highest electrocatalytic activity for accelerating the two-electron reduction of O-2 to H2O2. In addition, the electrocatalytic activity was enhanced when feeding with O-2 and at pH 12.8. The electrochemical reductive reaction of O-2 is typically a diffusion-controlled electrochemical process. The calculated values of k representing the mass transfer rate were in the order Pd0.5Fe0.5/graphene (0.379) > Pd-1.0/graphene (0.178) > Fe-1.0/graphene (0.175). The reduction peak currents for four CPs decreased in the order 3-chlorophenol (0.0214 mA) > 2,4,5-trichlorophenol (0.0190 mA)> 2,4-dichlorophenol (0.0188 mA)> 4-chlorophenol (0.0178 mA), indicating that the Pd0.5Fe0.5/graphene electrode would show the most powerful indirect electro-oxidation for 3-CP degradation in comparison with the other CPs. Therefore, the Pd0.5Fe0.5/graphene catalyst exhibits a higher electrocatalytic activity than the Pdto/graphene catalyst and Fe-1.0/graphene catalyst for the reductive dechlorination and indirect electrochemical oxidation of CPs. (C) 2016 Elsevier B.V. All rights reserved.