Nonprecious Bimetallic Iron-Molybdenum Sulfide Electrocatalysts for the Hydrogen Evolution Reaction in Proton Exchange Membrane Electrolyzers

In this study, we report the synthesis and characterization of nonprecious bimetallic iron-molybdenum sulfide bio-inspired electrocatalysts for the hydrogen evolution reaction (HER). Iron-molybdenum sulfide materials were obtained through three distinct scalable synthetic approaches using microwave irradiation or heat treatment in furnace under inert and reductive atmospheres. These electrocatalysts were combined with carbon nanotubes (CNTs), and their activity for the hydrogen evolution reaction (HER) was studied in acidic environment. The most efficient composite material of the series was obtained by microwave synthesis and displays a current density per geometric area of 10 mA.cm(-2) at an overpotential of 140 mV with unity faradic efficiency for hydrogen evolution. This composite cathode catalyst was implemented into a proton exchange membrane (PEM) electrolyzer single cell with iridium black as the anode catalyst and could be operated at 0.5 A.cm(-2), requiring less than 300 mV additional voltage compared to Pt and with remarkable stability during accelerated stress testing.