P-doped 3D graphene network supporting uniformly vertical MoS2 nanosheets for enhanced hydrogen evolution reaction

In order to optimize the conductivity of molybdenum disulfide (MoS2) and promote its large-scale application as a catalyst for hydrogen evolution, MoS2 is usually used to form composites with conductive materials, but these hybrid materials suffer from scare active sites, overlapping and complicate process. In this work, phosphoric acid is used as a builder of stereoscopic structures, which can not only twist graphene sheets into a P-doped three-dimensional (3D) graphene network but also promote surface electron transport between graphene sheets. Without adding additional framework materials such as carbon nano tubes or nickel foam, stereoscopic MoS2/graphene structures are formed with a large number of twisted graphene sheets to support the vertical growth of MoS2 and expose the edge sites of MoS2, showing a low Tafel slope about 35 mV dec(-1), a high current density of 900 mA cm(-2) at about 300 mV and a robust stability over 2000 cycles. Thus, this work shows a possibility to synthesize an efficient catalyst on a large-scale for hydrogen evolution reaction, which can promote the realization of hydrogen economy. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.