MoS ₂ -modified porous gas diffusion layer with air–solid–liquid interface for efficient electrocatalytic water splitting

The formation and adsorption of bubbles on electrodes weaken the efficiency of gas evolution reactions such as the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by hindering proton transfer and consuming nucleation energy. Herein, a triphase electrode was fabricated to address this limitation by immobilizing MoS2 nanosheets on a porous gas diffusion layer (GDL). This electrode shows a superior HER and OER ratio, high current density and stable working state in electrocatalytic water splitting. Moreover, by lowering the pressure behind the GDL, we further improved the water-splitting rate (the current density was three times higher than that of a bare MoS2 diphase electrode at -0.37 V for HER and 1.62 V for OER) and stability by eliminating the appearance of bubbles, even under a current density as high as 100 mA cm-2. Our work manifests the significance of constructing a triphase system for water splitting, and the system is also available for other gas evolution reactions.