In this study, the performance of transition metal oxysulfides as cathodes has been explored for a proton exchange membrane water electrolyzer (PEMWE). Simple electrodeposition and anion exchange methods provide facile control of the morphology and composition of NiyCo1-yOxSz catalysts deposited as gas diffusion electrodes on carbon paper substrates. After sulfidation, the overpotential for the hydrogen evolution reaction (HER) was significantly reduced and the intrinsic activity of the HER showed volcano behaviors as a function of the composition and binding energy of S in the electrodes. The PEMWE employing such a cathode demonstrates a reasonable current density of 0.72 A/cm(2) at a cell voltage of 2.0 V. The results presented herein demonstrate that the non-noble catalyst can be adopted as a cathode in PEMWE operation.