Self-supported Co–Mo sulfide in electrospun carbon nanofibers as electrocatalysts for hydrogen evolution reaction in alkaline medium

The development of high-efficiency and cheap electrocatalysts for hydrogen evolution reactions (HER) is of great importance for the electrochemical production of hydrogen. In this study, self-supported CoMoS on carbon nanofiber (CoMoS@CNF) catalysts were prepared through a one-step hydrothermal method using carbonized, electrospun polyacrylonitrile–dopamine (DA) polymeric fibers. The –OH group on DA was utilized to immobilize 1,2,3,4-Butanetetracarboxylic acid on the surface of the modified fiber, which consequently captured Co and Mo ions . Self-supported CoMoS nanosheet and nanosphere clusters grew on the surface of the CNF. The core–shell and layered nanosheet stacked structures created abundant accessible active sites, convenient ion diffusion pathways, and opened channels for the rapid release of the evolved H 2 . Density functional theory calculations showed that the heterojunctions constructed from CoS 2 and Mo 2 S 3 had low free energies for the adsorption of hydrogen. The prepared CoMoS@CNF electrode required a low overpotential (105.2 mV) to reach 10 mV cm −2 in 1 M KOH and showed no deterioration in the electrochemical performance even after 20 h of continuous operation at a 10 mV overpotential. The excellent activity and stability of the self-supported CoMoS@CNF electrocatalysts toward HER in alkaline medium is possibly due to its advantageous electronic and geometrical structure.