2D MoS 2 Binder‐Free Electrodes as Cathode Catalysts for Hydrogen Production in Proton Exchange Membrane Water Electrolyzers

Molybdenum disulfide (MoS 2 ) has emerged as a promising alternative to platinum‐based catalysts for the hydrogen evolution reaction (HER) at the cathode in PEM water electrolyzers. In this study, we report the development of large‐area, binder‐free MoS 2 electrocatalyst cathode synthesized via in‐situ hydrothermal growth on carbon cloth substrates, eliminating the need for binders and post‐synthesis processing, while enabling the formation of edge‐enriched MoS 2 nanosheets with abundant active sites. PEM cells with cathodes of on‐collector grown vertically aligned MoS 2 nanosheets (at 3 and 7 mg cm −2 loadings over 9.6 cm 2 area) could deliver a current density of 200 mA cm −2 at voltages as low as 2.09 and 1.94 V under ambient conditions. Chronoamperometric stability tests indicate gradual reduction of cell current (e.g., to ∼76% and ∼52% of the starting value in 1 and 8 h, at a catalyst loading of 3 mg cm −2 ) due to partial pitting and loss of the catalyst in microscopic patches from the carbon cloth, the excellent Faradaic efficiency (near 100%) and competitive overall HER activity of MoS 2 grown hydrothermally directly on the current collector holds promise of the technology for scalable and sustainable PEM water electrolyzer systems provided the support–catalyst interaction is optimized further.