▎ 摘　　要

The main purposes of this work were minimizing the levels of expensive electrocatalyst such as platinum and palladium for maximizing hydrogen evolution at low overpotentials. Here, different compositions of platinum and palladium nanoparticles were applied so that the minimum amount of platinum as a high efficient HER electrocatalyst was achieved. Moreover, a newly prepared nanocomposite, sulfonated graphene-based conductive polymer (poly(3,4 ethylene dioxythiophene), PEDOT), was used as a support of the loaded Pt and Pd nanoparticles. This prepared nanocomposite was assigned as PtxPd((1-x))NPs/ PEDOT SG, which x was changed from 0.0 to 1.0. Preparation and performance of this nanocomposite were characterized using various analytical and electrochemical methods. The results obtained from voltammetry and impedance spectroscopy studies indicated different electrochemical manners of the electrocatalyst towards reducing protons into hydrogen, contained various compositions of Pd and Pt. Among these results, the highest Tafel slope and exchange current, as well as the lowest overpotential, were respectively determined as 57 mV decade(-1), 0.301 mu A and 0.1726 V (vs. Ag/AgCl), when the HER was investigated at Pt(0,5)Pd(0,5)NPs/PEDOT SG/GCE. The nanocomposite remained stable until 500th cycle of the potential. Summarily, the results of this study were the preparation of the efficient, stable and lowcost HER electrocatalyst. (C) 2017 Elsevier Ltd. All rights reserved.