Scalable conformal MoSx catalyst for efficient hydrogen evolution at industrial-level current density in alkaline electrolyzers

The development of scalable, cost-effective fabrication strategies for electrodes is crucial for alkaline water electrolyzers (AWEs). Here, we present a coating-annealing method to conformally coat a MoS x catalyst layer onto a porous Ni foam (NF) substrate. By controlling the annealing conditions, the composition of the MoS x layer could be tuned from MoS 2 to MoS 3 , and its catalytic performance for hydrogen evolution reaction (HER) was optimized for alkaline media. The resulting MoS 3 @NF achieved industrially relevant HER current densities of 200 mA/cm 2 at a low overpotential of 246 mV, maintaining stable operation for over 240 h. The MoS 3 @NF cathode, combined with a stainless-steel anode, enabled an AWE cell to operate steadily at 1.96 V and 1 A/cm 2 for 1,000 h, surpassing most of the previously reported water electrolyzers employing MoS x -based cathodes. Overall, our work demonstrates the potential of MoS 3 , with abundant edge-sulfur active sites, as a high-performance cathode material for industrial AWEs.