Two-dimensional molybdenum disulfide and tungsten disulfide interleaved nanowalls constructed on silk cocoon-derived N-doped carbon fibers for hydrogen evolution reaction

Finding cost-effective, active and durable catalyst materials for energy applications, such as electrocatalytic hydrogen production, is an intriguing challenge. Here, a facile and effective approach to the design and construction of two-dimensional MoS2 and WS2 interleaved nanowalls with maximum exposures of active edges on silk-derived N-doped carbon fibers (SNCF) was demonstrated. The morphological evolutions of the MoS2 and WS2 nanocrystals on the SNCF from crescent-like nanosheets to an interleaved nanowall network can be obtained by adjusting the concentrations of the Mo and W precursors. These robust MoS2/SNCF and WS2/SNCF electrocatalysts exhibit prominent hydrogen evolution reaction (HER) activities with onset potentials of -40 and -96 mV and Tafel slopes of 60 and 66 mV dec(-1), respectively. The overpotentials (eta) at j = -10 mA cm(-2) for MoS2/SNCF and WS2/SNCF are -102 and -157 mV, respectively. In addition, MoS2/SNCF and WS2/SNCF are both able to sustain continuous HER operation for 10 h under working conditions with only a slight degradation in current densities, implying excellent durability and a prospect for practical applications. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.