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

Abstract 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 MoS 2 and WS 2 interleaved nanowalls with maximum exposures of active edges on silk-derived N-doped carbon fibers (SNCF) was demonstrated. The morphological evolutions of the MoS 2 and WS 2 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 MoS 2 /SNCF and WS 2 /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 ( η ) at j  = −10 mA cm −2 for MoS 2 /SNCF and WS 2 /SNCF are −102 and −157 mV, respectively. In addition, MoS 2 /SNCF and WS 2 /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.