A strategy to synergistically increase the number of active edge sites and the conductivity of MoS2 nanosheets for hydrogen evolution

Abstract

Nanostructured MoS₂ is very promising as an electrocatalyst for hydrogen evolution due to a greater number of active edge sites. However, a very large resistance between basal planes decreases the overall efficiency of hydrogen evolution, and greatly limits its application in industry. Herein we develop a facile strategy to synergistically increase the number of active edge sites and the conductivity of MoS₂. MoS₂ nanosheet arrays can be grown vertically on a carbon fiber cloth (CFC) substrates by a facile strategy. On the one hand, ammonium fluoride in the reaction system could effectively etch the inert basal plane of the MoS₂ nanosheets, leading to the formation of pits in the inert basal plane of the MoS₂ nanosheets. Thereby the number of active edge sites is significantly increased. On the other hand, the vertical growth of MoS₂ nanosheet arrays on CFCs can significantly decrease the resistance of MoS₂-based electrocatalysts. As a result, the MoS₂-based electrocatalysts exhibit excellent catalytic activity for hydrogen evolution reactions, with a small Tafel slope and a large cathodic current density. Moreover, the CFC can be repeatedly utilized as a template to grow ultrathin MoS₂ nanosheet arrays for HERs. The excellent activity and recyclable utilization, as well as mass production, indicate that the composite has promising applications in industry.