The polymer electrolyte membrane (PEM)-based electrolysis technology is a promising mean to split water and store renewable energy in the form of clean fuel, hydrogen. However, its high price due to the use of platinum group metals (PGMs) as catalyst materials generally makes the technology cost-restrictive. Herein we present the performance evaluation of cobalt oxide in PEM electrolysis as cathode catalyst where hydrogen evolution reaction (HER) takes place. Performance comparison of non-PGM catalysts (CoO, Co₃O₄and MoS₂) revealed that better performance was attained with Co₃O₄ and it was further improved by mixing with an electrically conducting carbon material (Vulcan). An optimum amount of the carbon additive was found, and the best performance was recorded at 47 wt% Co₃O₄ over the total amount. At 2.05 V, 47 wt% Co₃O₄-based catalyst (0.55 A/cm²) outperformed 47 wt% MoS₂-based one (0.51 A/cm²). More importantly, the performance of the former at 2.3 V (1.12 A/cm²) surpassed even that of Pt-black (1.11 A/cm²). In situ XAS study of the Co₃O₄-based material under PEM electrolysis conditions revealed dynamic interchange of Co³⁺ and Co²⁺ fractions, which was attributed to ultimately boost the HER performance.