Morphology/phase-dependent MoS2 nanostructures for high-efficiency electrochemical activity

Abstract

Molybdenum disulfide (MoS2), as a classic two-dimensional material, is limited in applications with its relatively poor conductivity and chemical instability due to its single morphology/phase structure in electrocatalytic activity and specific capacitance. Moreover, up to date, it is still an open area in establishing cost-effective approaches to fabricate exotic MoS2 nanostructures with desired morphology and phase component for exhibiting excellent performance in energy conversion and storage. Herein, only using extremely ordinary sources of molybdenum and sulfur and a simple one-pot hydrothermal method, we efficiently and economically synthesized two types of stable MoS2 nanostructures with a certain percentage of the metastable metallic (1T) phase, i.e., spherical nanoflowers (SNF) and random nanosheets (RNS). Both SNF–MoS2 and RNS-MoS2 exhibited excellent electrocatalytic activity for hydrogen evolution reaction with ultra-high stability and high specific capacitance. These remarkable properties are due to the dramatically increased number of active sites in these unique nanostructures and their enhanced electric conductivities due to the metallic 1T phase. Furthermore, when these two types of nanostructures are physical decorated with carbon black, their electrocatalysis is further enhanced. Our findings offer an economical approach to fabricate stable MoS2-based nanomaterials for practical applications with highly efficient energy conversion and energy storage.