An open-structured carbon fiber brush electrode for efficient hydrogen evolution by inducing oriented bubble transport

Abstract

Hydrogen, as a promising energy carrier to alleviate the global issues of energy crisis, has arisen a worldwide concern. However, the lack of management of the produced bubbles on electrode surface is one of the critical barriers for hydrogen evolution reaction (HER) since insufficient bubble removal causes the blockage of the active sites, increased ohmic resistance in the electrolyte and deficient ion transfer from the bulk solution to the electrode surface. In this study, an open-structured carbon fiber brush electrode (CFB) that can be produced by simply twisting a folded Ti wire fitted with carbon fibers was proposed. As a proof-of-concept demonstration, an earth-abundant electrocatalyst, MoS2 nanosheets was loaded on the CFB via solvothermal method to fabricate the HER electrode (MoS2⊥CFB). This structure not only ensures a uniform electrocatalyst distribution throughout the exterior and internal electrode surface but also ensures an improved exposure of active sites and a sufficient reaction ion supply by inducing oriented hydrogen bubble transport during the electrochemical process. Additionally, the open structure of CFB accelerates fluid flow around the electrode, which also guarantees a sufficient proton supply and hydrogen bubble removal. As a results, MoS2⊥CFB exhibits a 3.7 times higher current density at an overpotential of 400 mV and prominent durability as compared with the same catalyst growing on the common carbon cloth substrate.